Differentiation between Cystic Pituitary Adenomas and Rathke Cleft Cysts: A Diagnostic Model Using MRI

Natural history and predictors of growth in conservatively managed non-functioning pituitary macroadenomas: A volumetric study of 232 tumors

BACKGROUND

Although patients with clinically non-functioning pituitary macroadenomas (NFPMAs) are typically monitored without immediate therapeutic intervention, their natural course remains unclear. This study aimed to characterize growth dynamics in conservatively managed NFPMAs and identify clinical predictors of tumor progression using volumetric MRI analysis.

METHODS

We retrospectively analyzed 232 patients with NFPMAs who underwent at least two high-resolution MRI scans over a minimum follow-up of 12 months without therapeutic intervention. Tumor volumes were assessed using semi-automated segmentation. Progression was defined as a ≥ 20 % increase in volume. Clinical and radiological variables were evaluated to identify predictors of growth.

RESULTS

Over a median follow-up of 37 months, 110 tumors (47.4 %) demonstrated significant growth. The median initial tumor volume was 1.9 cm³ , with median absolute and relative annual growth rates of 0.13 cm³ /year and 5.47 %/year, respectively. Multivariate Cox regression identified larger initial tumor volume (HR 1.140, 95 % CI 1.005-1.081; p = 0.027) and female sex (HR 1.594, 95 % CI 1.076-2.361; p = 0.020) as independent predictors. A tumor volume threshold of 2.5 cm³ was associated with increased growth risk. Among age-matched groups, females exhibited greater volumetric growth than males.

CONCLUSION

Approximately half of NFPMAs exhibit slow but measurable growth over time. Tumor volume at diagnosis and female sex are significant predictors of progression. These findings underscore the importance of individualized surveillance strategies, particularly for female patients with larger baseline tumors, and provide clinically relevant data to inform long-term management of NFPMAs.

Rathke's cleft cyst: From history to molecular genetics

A Rathke's cleft cyst (RCC) is a remnant of the embryologic Rathke's pouch and a common pituitary lesion. A true RCC is lined with ciliated cuboidal or columnar epithelia with occasional goblet cells and squamous metaplasia. A RCC is frequently diagnosed incidentally through magnetic resonance imaging and computed tomography of the brain or pituitary gland. Presentation can range from an asymptomatic clinical picture to a rapidly progressive disease. RCC are located most often in the sellar and suprasellar regions and a careful differential diagnosis is crucial, especially to exclude craniophryngioma. Recent studies illuminate novel molecular mechanisms and markers for understanding the pathogenesis of RCC. PROP-1, a paired-like homeodomain transcription factor, controls pituitary ontogeny and its high expression induces RCCs. Both transgenic mouse models and immunohistochemical analysis of human RCCs indicate that the leukemia inhibitory factor is involved in pathogenesis. The expression of cytokeratins 8 and 2 in RCCs, but not in craniopharyngiomas, and the presence of beta-catenin mutations in many craniopharyngiomas, but not in RCCs, help with the differential diagnosis. For asymptomatic and small RCCs, observation is appropriate, with serial magnetic resonance imaging and hormonal investigation depending on the patient's clinical status. Surgical resection may be required for symptomatic RCC and recurrence rates are generally low. For patients with a recurrence, stereotactic radiosurgery is an effective approach with low risk.

A Data-Driven Approach for Rathke's Cleft Cysts Management

Background: Rathke's cleft cysts (RCCs) are non-neoplastic and rare sellar lesions derived from remnants of Rathke's pouch. While asymptomatic RCCs often require only conservative management, symptomatic cases may necessitate surgical intervention. The aim of our study is to investigate the correlations between clinical, radiological and histological features of RCCs to propose a novel management model. Methods: We conducted a retrospective analysis from patients who underwent surgery for cystic lesions between 2013 and 2023 in the Neurosurgery Department of Treviso Hospital (Italy) using for our purpose only those confirmed by histological specimen as RCCs. Results: 20 patients for a total of 24 procedures (20 primary surgeries/4 cases for recurrence) were performed for RCCs. A gross total resection was achieved in 23 cases, resulting in improvement of headache and visual symptoms in all patients. Hyperintensity on T1-weighted MRI sequences is more strongly correlated with inflammation and with intralesional metaplasia (p = 0.009). Both characteristics are involved in the development of hypopituitarism (p = 0.057), headache, and visual impairment (p = 0.082) compared to cysts with CSF-like content, even when the latter are smaller in size (p = 0.078). Discussion and Conclusions: RCCs are rare lesions whose management is challenging due to a lack of established guidelines. Intraoperative cystic content and MRI cystic characteristics seem to correlate with clinical presentation and long-term outcome in these patients. The transsphenoidal endoscopic approach is a safe and effective treatment, especially in cysts with inflammatory aspect in histopathological specimens and in dedicated MRI sequences that could take advantage of an early surgical resection. A decision-making model based on clinical, radiological and histopathological features of cysts could be useful to guide RCCs' treatment, underlining the role of inflammation that seems to be involved in the onset of visual and hormonal impairment and in recurrence risk.

Comparison of clinical and radiological characteristics of inflammatory and non-inflammatory Rathke cleft cysts

PURPOSE

Rathke cleft cysts are commonly encountered sellar lesions, and their inflammation induces symptoms and recurrence. Cyst wall enhancement is related to inflammation; however, its range and frequency have not yet been investigated. This study aimed to investigate the clinical and radiological differences between inflammatory and non-inflammatory Rathke cleft cysts.

METHODS

Forty-one patients who underwent cyst decompression surgery for Rathke's cleft cysts between January 2008 and July 2022 were retrospectively analyzed. Based on the pathological reports, patients were divided into inflammatory and non-inflammatory groups. Clinical assessments, endocrinological evaluations, cyst content analysis, and imaging metrics (mean computed tomographic value, maximum diameter, mean apparent diffusion coefficient [ADC] value, and qualitative features) were analyzed. Receiver operating characteristic curve analysis was performed, to determine ADC cutoff values, for differentiating inflammatory group from non-inflammatory group.

RESULTS

Totally, 21 and 20 cases were categorized into the inflammatory and non-inflammatory groups, respectively. The inflammatory group displayed a higher incidence of central diabetes insipidus (arginine vasopressin deficiency) (p = 0.04), turbid cyst content (p = 0.03), significantly lower mean ADC values (p = 0.04), and more extensive circumferential wall enhancement on magnetic resonance imaging (MRI) (p < 0.001). In the inflammatory group, all cases revealed circumferential wall enhancement, with some exhibiting thick wall enhancement. There were no significant differences in other radiological features. The ADC cutoff value for differentiating the two groups was 1.57 × 10-3 mm2/s, showing a sensitivity of 81.3% and specificity of 66.7% CONCLUSION: Inflammatory Rathke cleft cysts tended to show a higher incidence of central diabetes insipidus and turbid cyst content. Radiologically, they exhibited lower mean ADC values and greater circumferential wall enhancement on MRI.

Inflammation of adenohypophysis is commonly associated with headache in surgically managed Rathke's cleft cysts

PURPOSE

Rathke's cleft cysts (RCC) are present in up to 20% of autopsy studies but only a minority necessitate surgical treatment. Inflammation of RCC is thought to be significant in three processes: the development of classical symptoms, a predisposition to rupture or apoplexy, and increasing the rate of RCC recurrence. We aim to characterize clinical presentation, histological and radiological findings in patients with surgically managed RCC.

METHODS

We conducted a retrospective case series of 31 RCC, which had undergone surgical management between April 2016 and April 2024. Histopathology and radiology were independently reviewed by neuropathologist and neuroradiologist, and case notes were reviewed for clinical and biochemical data.

RESULTS

Median age was 43 years (IQR 32-63); 77% were female. 23/31 demonstrated inflammation of RCC cyst epithelium (n = 13), cyst wall (n = 20) or anterior pituitary (adenohypophysitis) (n = 12). 8 cases were not inflamed. Preoperative features included pituitary dysfunction (70%), headache (65%), visual disturbance (26%) and polyuria/polydipsia (7%). Six patients presented with features of apoplexy. Headache was more prevalent (92%) in patients with adenohypophysitis vs. those without (47%), p = 0.020, and present in all 11 cases where inflammation in the adenohypophysis was chronic. Pituitary dysfunction was not associated with inflammation overall (76% vs. 70% p = ns), nor specifically within the adenohypophysis (75 vs. 63% p = 0.69). Histological inflammation was associated with radiological loss of posterior bright spot (70% vs. 14% p = 0.024).

CONCLUSION

Headache but not pituitary dysfunction was associated with adenohypophyseal inflammation. A trend of increasing headache prevalence was seen with increasing degree of inflammatory infiltrate within RCC.

A nonsecreting suprasellar ectopic pituitary adenoma: A case report

A pituitary adenoma in the suprasellar region without involvement of the Sella turcica is uncommon, with few examples recorded in the literature. Imaging, particularly magnetic resonance imaging, is critical for diagnosis. Radiological features aid in distinguishing ectopic pituitary adenoma from other possible diagnoses, which include Rathke cleft cyst, suprasellar abscess, diabetes insipidus, suprasellar cellular infiltrate, and suprasellar tumors such as germinoma, craniopharyngioma, optic pathway glioma, suprasellar hemangioblastoma, and pituitary lymphoma. A 48-year-old lady with impaired visual acuity underwent an MRI, which revealed a suprasellar ectopic pituitary adenoma in contact with the pituitary stalk and optic chiasm.

Differentiating Cystic Lesions in the Sellar Region of the Brain Using Artificial Intelligence and Machine Learning for Early Diagnosis: A Prospective Review of the Novel Diagnostic Modalities

This paper investigates the potential of artificial intelligence (AI) and machine learning (ML) to enhance the differentiation of cystic lesions in the sellar region, such as pituitary adenomas, Rathke cleft cysts (RCCs) and craniopharyngiomas (CP), through the use of advanced neuroimaging techniques, particularly magnetic resonance imaging (MRI). The goal is to explore how AI-driven models, including convolutional neural networks (CNNs), deep learning, and ensemble methods, can overcome the limitations of traditional diagnostic approaches, providing more accurate and early differentiation of these lesions. The review incorporates findings from critical studies, such as using the Open Access Series of Imaging Studies (OASIS) dataset (Kaggle, San Francisco, USA) for MRI-based brain research, highlighting the significance of statistical rigor and automated segmentation in developing reliable AI models. By drawing on these insights and addressing the challenges posed by small, single-institutional datasets, the paper aims to demonstrate how AI applications can improve diagnostic precision, enhance clinical decision-making, and ultimately lead to better patient outcomes in managing sellar region cystic lesions.

Rathke's cleft cyst apoplexy presented as pituitary apoplexy: A case report

INTRODUCTION AND IMPORTANCE

Rathke's cleft cyst (RCC) are non-malignant lesions arising from remnants of Rathke's pouch in the pituitary gland. Apoplexy is seen commonly in pituitary macroadenomas but very rarely in RCCs.

CASE PRESENTATION

A 30-year-old male presented with a severe headache and vomiting. Imaging revealed an enlarged pituitary gland with possible hemorrhage in a RCC. The cyst was evacuated with endonasal transsphenoidal surgery, and histology confirmed RCC. Follow-up imaging showed complete cyst resolution, although he required levothyroxine for hypothyroidism.

CLINICAL DISCUSSION

The occurrence of hemorrhage within RCCs, although rare, mimics pituitary tumor apoplexy often complicating the diagnosis. The management is similar to pituitary tumor apoplexy, primarily involving surgical intervention. Postoperative care may require long-term hormonal replacement therapy in a significant number of patients.

CONCLUSION

This report underscores the importance of considering RCC in the differential diagnoses of pituitary lesions with hemorrhage with promising surgical outcome.

Spontaneous regression of paediatric pituitary lesions-report of 2 cases and literature review

OBJECTIVE

Pituitary lesions are rare in the pediatric population. They consist of a heterogenous group of neoplasms including pituitary adenomas (PA) and Rathke cleft cysts (RCC). Their natural history, management strategies, and long-term outcomes are mostly extrapolated from adult experience. Neurosurgical intervention may be necessary for large and/or symptomatic lesions. Of note, the likelihood of their spontaneous regression is uncommon. We report 2 interesting cases of such a phenomenon for these lesions and discuss our findings in corroboration with current literature.

METHODS AND RESULTS

Two cases of spontaneous regression of pituitary lesions observed on serial neuroimaging are described. Based on their clinical history and radiological characteristics, the working diagnoses were that of a non-functioning PA and RCC, respectively. A systematic search of relevant publications in the English language is performed in PubMed and Google Scholar. Our findings show that there are 14 reported cases (including 1 of our patients) of spontaneous regression of non-functioning PA with good outcomes. Pertaining to RCCs, the limited evidence suggests that the incidence of their spontaneous regression is approximately 30%, similar to what is reported in the adult population. A separate discussion on the possible differential diagnosis of lymphocytic hypophysitis is also highlighted.

CONCLUSION

Pediatric pituitary lesions may present with unpredictable natural histories, as highlighted in our case examples. We advocate an extended period of follow-up by a cohesive multidisciplinary team. In meantime, collaborative efforts should focus on the establishing clinical practice guidelines to optimize the management of pituitary lesions in children.

Recurrent femoral neck fractures: keep an eye out for Cushing's syndrome

Prolonged glucocorticoid overexposure leads to Cushing's syndrome (CS). It is characterised by diverse metabolic, cardiovascular and bone mineral manifestations. A middle-aged woman presented for a preoperative evaluation of a pathological fracture of the left neck of the femur. She had a history of a hip fracture on the opposite side 3 years back. She exhibited several features specific to CS and was subsequently diagnosed with Cushing's disease. She underwent transsphenoidal adenoma resection and achieved remission. Glucocorticoids primarily affect the trabecular bone compared with cortical bones, and vertebral fractures are common in CS. The femoral neck consists of both trabecular and cortical bone and can be involved in CS. Our patient was not diagnosed as CS at the first pathological fracture and was subsequently diagnosed only after the second fracture. This case report underscores the importance of a diligent search for a possible endocrinological aetiology in any case of pathological fractures.

Rathke's cleft cysts: from pathophysiology to management

Rathke's cleft cysts (RCCs) are benign, non-neoplastic lesions located in the sellar and suprasellar regions of the brain, originating from remnants of Rathke's pouch, an embryonic precursor to the anterior pituitary gland. Although RCCs are frequently asymptomatic and discovered incidentally during imaging studies, they can present with a variety of symptoms, including headaches, visual disturbances, and endocrine dysfunction due to the compression of adjacent neural structures. The management of RCCs is particularly challenging, as the decision to pursue conservative monitoring or surgical intervention depends heavily on the cyst's size, growth potential, and the severity of symptoms. Transsphenoidal surgery is the primary treatment for symptomatic RCCs, offering effective relief from symptoms through decompression of the cyst. However, recurrence remains a significant issue, with rates reported up to 33%, prompting debates about the extent of cyst wall removal during surgery. Recent advancements in minimally invasive endoscopic techniques have improved surgical outcomes, yet the risk of postoperative complications such as hypopituitarism and cerebrospinal fluid leaks persists. Additionally, stereotactic radiosurgery has emerged as a potential alternative for patients with recurrent RCCs or those who are not suitable candidates for repeat surgery. Despite its promise, the long-term safety and efficacy of radiotherapy in RCC management require further investigation. This narrative review aims to provide a comprehensive overview of RCCs, integrating the latest research and clinical guidelines to discuss pathophysiology, clinical presentation, and management strategies, emphasizing the need for a personalized approach to treating this complex condition.

A Peculiar Case of Cabergoline Response to a Non-functioning Cystic Pituitary Adenoma in a Young Adult Male

We present an interesting case of a cystic, pituitary adenoma that showed up insidiously with non-traditional clinical symptoms. The standard of care for non-functioning pituitary adenomas is transsphenoidal surgery. However, with pharmacotherapy using cabergoline (a dopamine receptor agonist), the patient had a near disappearance of the tumor. This case report seeks to add to the medical literature the possibility of pharmacotherapy for treating non-functional pituitary adenomas.

Approaches to supratentorial brain tumours in children

The differential diagnosis of supratentorial brain tumours in children can be challenging, especially considering the recent changes to the WHO classification of CNS tumours published in 2021. Many new tumour types have been proposed which frequently present in children and young adults and their imaging features are currently being described by the neuroradiology community. The purpose of this article is to provide guidance to residents and fellows new to the field of paediatric neuroradiology on how to evaluate an MRI of a patient with a newly diagnosed supratentorial tumour. Six different approaches are discussed including: 1. Tumour types, briefly discussing the main changes to the recent WHO classification of CNS tumours, 2. Patient age and its influence on incidence rates of specific tumour types, 3. Growth patterns, 4. Tumour location and how defining the correct location helps in narrowing down the differential diagnoses and 5. Imaging features of the tumour on DWI, SWI, FLAIR and post contrast sequences.

Natural history and surgical outcomes of Rathke's cleft cysts: a Spanish multicenter study

Rathke's cleft cysts (RCC) are a common type of lesion found in the sellar or suprasellar area. They are usually monitored clinically, but in some cases, surgery may be required. However, their natural progression is not yet well understood, and the outcomes of surgery are uncertain. The objective of this study is to evaluate the natural history of Rathke's cleft cysts in patients who are clinically monitored without treatment, and to determine the outcomes of surgery and the incidence of recurrences over time.

Design and patients

National multicentric study of patients diagnosed of Rathke's cleft cyst (RCC- Spain) from 2000 onwards and followed in 15 tertiary centers of Spain. A total of 177 patients diagnosed of RCC followed for 67.3 months (6-215) and 88 patients who underwent surgery, (81 patients underwent immediate surgery after diagnosis and 7 later for subsequent growth) followed for 68.8 months (3-235).

Results

The cyst size remained stable or decreased in 73.5% (133) of the patients. Only 44 patients (24.3%) experienced a cyst increase and 9 of them (5.1%) experienced an increase greater than 3 mm. In most of the patients who underwent surgery headaches and visual alterations improved, recurrence was observed in 8 (9.1%) after a median time of 96 months, and no predictors of recurrence were discovered.

Conclusions

Rathke's cleft cysts without initial compressive symptoms have a low probability of growth, so conservative management is recommended. Patients who undergo transsphenoidal surgery experience rapid clinical improvement, and recurrences are infrequent. However, they can occur after a long period of time, although no predictors of recurrence have been identified.

Accurate preoperative diagnosis of a Rathke cleft cyst with the aid of a novel classification for sellar cystic lesions and a diagnostic algorithm decision: Tools for differentiating cystic sellar lesions with a representative case

Background

Rathke's cleft cyst (RCC) is a benign lesion in the sellar and suprasellar compartments. Similarly, pituitary adenomas can present with cystic morphology, making it a differential diagnosis when evaluating a patient with a cystic lesion in the sellar region. Surgical goals differ between RCCs and pituitary adenomas as the first can achieve remission of symptoms with cyst decompression in contrast to pituitary adenomas where complete resection would be the main goal. Imaging analysis alone may not be sufficient to define a preoperative surgical plan. The combination of imaging and conjoined use of validated tools may provide valuable insights to the clinician when defining a surgical approach.

Case Description

We present a case of a 27-year-old male with a 3-month history of visual disturbances and headaches. Magnetic resonance imaging showed a cystic lesion in the sellar compartment with compression of nearby structures. The authors were able to accurately diagnose this sellar lesion as an RCC with the conjoined aid of two classifications proposed in the literature. Cyst evacuation was performed with relief of symptoms and improved visual outcomes at follow-up.

Conclusion

While cystic adenomas can require total resection for cure, RCCs can show marked improvement with partial resection and evacuation of its contents. An accurate preoperative diagnosis can lead the surgeon to opt for the best surgical approach.

A Novel Fusion of Radiomics and Semantic Features: MRI-Based Machine Learning in Distinguishing Pituitary Cystic Adenomas from Rathke's Cleft Cysts

Objectives

To evaluate the performances of machine learning using semantic and radiomic features from magnetic resonance imaging data to distinguish cystic pituitary adenomas (CPA) from Rathke's cleft cysts (RCCs).

Materials and Methods

The study involved 65 patients diagnosed with either CPA or RCCs. Multiple observers independently assessed the semantic features of the tumors on the magnetic resonance images. Radiomics features were extracted from T2-weighted, T1-weighted, and T1-contrast-enhanced images. Machine learning models, including Support Vector Machines (SVM), Logistic Regression (LR), and Light Gradient Boosting (LGB), were then trained and validated using semantic features only and a combination of semantic and radiomic features. Statistical analyses were carried out to compare the performance of these various models.

Results

Machine learning models that combined semantic and radiomic features achieved higher levels of accuracy than models with semantic features only. Models with combined semantic and T2-weighted radiomics features achieved the highest test accuracies (93.8%, 92.3%, and 90.8% for LR, SVM, and LGB, respectively). The SVM model combined semantic features with T2-weighted radiomics features had statistically significantly better performance than semantic features only (p = 0.019).

Conclusion

Our study demonstrates the significant potential of machine learning for differentiating CPA from RCCs.

Endoscopic endonasal surgery of Rathke's cleft cysts-- preoperative imaging evaluation, personalized removal and multilevel sellar floor reconstruction

OBJECTIVES

The purpose of this study was to evaluate the effectiveness of endoscopic endonasal surgery (EES) for Rathke's cleft cysts (RCCs) and the advantages of detailed preoperative imaging evaluation, intraoperative personalized removal and multilevel sellar floor reconstruction.

METHODS

The clinical data of 43 patients with RCCs who were treated by EES in the neurosurgery department of affiliated hospital of Jiangnan University and Wuxi No.2 People's Hospital from January 2018 to January 2023 were retrospectively analyzed. The effectiveness of EES for RCCs was analyzed by imaging information, surgical procedures, symptom improvement and complications.

RESULTS

All 43 RCCs were completely removed by EES, and all clinical symptoms improved to varying degrees. Postoperative relief of headache was achieved in 23 out of 26 patients (88.5 %); there was improvement in 10 out of 13 patients with visual field disorders (76.9 %) and in 8 out of 10 patients with endocrine abnormalities (80 %). New hormonal deficiency was discovered in 7 of all the patients postoperatively. There were 8 patients with postoperative diabetes insipidus and 1 patient with cerebrospinal fluid leakage. The incidence of new hormonal dysfunction and postoperative DI in expanded EES (33.3 %, 33.3 %) was higher than it in conventional EES (4 %, 8 %) (P < 0.05). The average follow-up time was 29.1 ± 14.8 months, and there were no deaths or infections. Three patients presented with cyst recurrence on MRI.

CONCLUSIONS

The clinical manifestations and imaging characteristics of RCCs are variable, and a detailed preoperative review of the imaging is helpful for the development of surgical plans. RCCs can be treated more safely and thoroughly with less trauma and complications by intraoperative personalized removal and multilevel sellar floor reconstruction. The high incidence of new hormonal dysfunction and postoperative DI may be related to the disturbance of the pituitary stalk. EES has unique advantages and high clinical application value for the treatment of RCCs.

Suggestion of Follow-Up Period in Nonfunctioning Pituitary Incidentaloma Based on MRI Characteristics

BACKGROUND

For patients diagnosed with asymptomatic, non-functional pituitary incidentaloma (PI), periodic follow-up is generally proposed. However, the recommended follow-up period differs among existing guidelines and consensus is lacking. Thus, this study aimed to suggest follow-up periods for PI based on MRI characteristics.

METHODS

Between 2007 and 2023, 245 patients who were diagnosed with PI were retrospectively assessed. Their mean clinical and neuroradiological follow-up periods were 74.2 and 27.3 months, respectively. Their baseline clinical and neuroradiological characteristics were analyzed. These 245 patients were divided into two groups: those with PI size progression and those without PI size progression. Additionally, neuroradiological features of each group were analyzed according to presumptive diagnoses of PI.

RESULTS

PI size increased in 33 of 245 patients. For the remaining 212 patients, PI size decreased or stayed unchanged. Of the 33 patients with PI size progression, ten underwent surgery. Stalk deviation (p<0.001) and lesion enhancement (p=0.001) were significantly more observed in those with PI size progression than in those without PI size progression. MRI morphological factors were not related to changes in PI size in the presumptive Rathke's cleft cyst group. In the presumptive pituitary adenoma group, absence of tumor enhancement (p<0.001) and stalk deviation (p<0.001) were significantly associated with tumor reduction and progression, respectively.

CONCLUSION

Our findings support an additional guideline for patients with asymptomatic non-functional PI without stalk deviation and enhancement. For these patients, the clinical and neuroradiological follow-up periods could be reduced.

Vertical triband flag sign for differential diagnosis of Rathke's cleft cyst

Background

The Rathke cleft cyst (RCC) is a type of cystic growth that is benign, circular, and well-defined with an incidence rate of 4 %. This study aims to identify a useful diagnostic imaging sign that can aid in the differentiation of RCC from other cystic lesions.

Methods

We retrospectively analyzed the records of 42 symptomatic RCC patients who were referred to our facility between 2016 and 2023. The data for the study were obtained from our electronic database. All magnetic resonance imaging (MRI) studies were performed using a 1.5-T superconducting magnetic scanner. All patients underwent endonasal transsphenoidal surgical resection. All MRIs were reviewed and evaluated by a neurosurgeon and a neuroradiologist.

Results

There were 8 (19 %) males and 34 (81 %) females with a mean age of 37.2-years. Our study identified a distinct imaging characteristic in 38 of the cases, which we have named the "vertical triband flag sign", due to the growth of the cyst developing a specific appearance. The flag sign was mostly observed only in the T1-images (71.5 %), while in four cases the sign was spotted only in T2-images, and in four cases it appeared in both T1 and T2. In 4 cases, the flag sign was not observed in which further investigations revealed that these cases were suprasellar or small sellar RCCs. The dot sign, which is a characteristic finding in RCCs was only observed in one of our cases.

Conclusion

Early diagnosis of RCCs may be facilitated by utilizing the vertical triband flag sign.

Machine Learning Approaches to Differentiate Sellar-Suprasellar Cystic Lesions on Magnetic Resonance Imaging

Cystic lesions are common lesions of the sellar region with various pathological types, including pituitary apoplexy, Rathke's cleft cyst, cystic craniopharyngioma, etc. Suggested surgical approaches are not unique when dealing with different cystic lesions. However, cystic lesions with different pathological types were hard to differentiate on MRI with the naked eye by doctors. This study aimed to distinguish different pathological types of cystic lesions in the sellar region using preoperative magnetic resonance imaging (MRI). Radiomics and deep learning approaches were used to extract features from gadolinium-enhanced MRIs of 399 patients enrolled at Peking Union Medical College Hospital over the past 15 years. Paired imaging differentiations were performed on four subtypes, including pituitary apoplexy, cystic pituitary adenoma (cysticA), Rathke's cleft cyst, and cystic craniopharyngioma. Results showed that the model achieved an average AUC value of 0.7685. The model based on a support vector machine could distinguish cystic craniopharyngioma from Rathke's cleft cyst with the highest AUC value of 0.8584. However, distinguishing cystic apoplexy from pituitary apoplexy was difficult and almost unclassifiable with any algorithms on any feature set, with the AUC value being only 0.6641. Finally, the proposed methods achieved an average Accuracy of 0.7532, which outperformed the traditional clinical knowledge-based method by about 8%. Therefore, in this study, we first fill the gap in the existing literature and provide a non-invasive method for accurately differentiating between these lesions, which could improve preoperative diagnosis accuracy and help to make surgery plans in clinical work.

MR Imaging Appearance of Ruptured Rathke Cleft Cyst and Associated Bone Marrow Enhancement

Rathke cleft cysts are common cystic pituitary lesions seen on MR imaging. A subset of Rathke cleft cysts can rupture within the sella and are uncommon. The imaging appearance of a ruptured Rathke cleft cyst has been previously described with nonspecific imaging findings. We present 7 cases of ruptured Rathke cleft cysts and basisphenoid bone marrow enhancement below the sella that could be used to potentially distinguish a ruptured Rathke cleft cyst from other cystic lesions.

Follicular carcinoma of the thyroid presenting as metastasis in the wall of an arachnoid cyst

The brain is an uncommon site for metastases of differentiated thyroid carcinoma with the most common location being cerebral hemispheres, followed by cerebellum and pituitary gland. Metastasis in the wall of an arachnoid cyst is exceedingly rare with single case report available in the published literature. Arachnoid cyst metastasis from an extraneuraxial malignancy has not been published until. We present a unique case of thyroid carcinoma metastasizing to the wall of an intracranial arachnoid cyst and the most interesting fact is that it was the first clinical manifestation of her malignancy.

Differentiation of pure cystic sellar lesions on magnetic resonance imaging

BACKGROUND AND PURPOSE

Cystic pituitary adenomas and cystic craniopharyngiomas may mimic Rathke cleft cysts when there is no solid enhancing component on magnetic resonance imaging (MRI). This study aims to investigate the efficiency of MRI findings in differentiating Rathke cleft cysts from pure cystic pituitary adenoma and pure cystic craniopharyngioma.

MATERIALS AND METHODS

109 patients were included in this study (56 Rathke cleft cysts, 38 pituitary adenomas, and 15 craniopharyngiomas). Preoperative magnetic resonance images were evaluated using 9 imaging findings. These findings include intralesional fluid-fluid level, intralesional septations, midline /off-midline location, suprasellar extension, an intracystic nodule, a hypointense rim on T2-weighted images, ≥ 2 mm thickness of contrast-enhancing wall, T1 hyperintensity and T2 hypointensity. p < 0.01 was considered statistically significant.

RESULTS

There was a statistically significant difference among groups for these 9 findings. Intracystic nodule and T2 hypointensity were the most specific MRI findings in differentiating Rathke cleft cyst from the others (98.1% and 100%, respectively). Intralesional septation and thick contrast-enhancing wall were the most sensitive MRI findings ruling out Rathke cleft cysts with 100% sensitivity.

CONCLUSION

Rathke cleft cysts can be distinguished from pure cystic adenoma and craniopharyngioma with the presence of an intracystic nodule, T2 hypointensity, the absence of the thick contrast-enhancing wall, and absence of intralesional septations.

Clinical and imaging findings for the evaluation of large Rathke's cleft cysts and cystic craniopharyngiomas

PURPOSE

Large Rathke's cleft cysts (LRCCs) and cystic craniopharyngiomas (CCPs) arise from the same embryological origin and may have similar MR presentations. However, the two tumors have different management strategies and outcomes. This study was designed to evaluate the clinical and imaging findings of LRCCs and CCPs, aiming to evaluate their pretreatment diagnosis and outcomes.

METHODS

We retrospectively enrolled 20 patients with LRCCs and 25 patients with CCPs. Both tumors had a maximal diameter of more than 20 mm. We evaluated the patients' clinical and MR imaging findings, including symptoms, management strategies, outcomes, anatomic growth patterns and signal changes.

RESULTS

The age of onset for LRCCs versus CCPs was 49.0 ± 16.8 versus 34.2 ± 22.2 years (p = .022); the following outcomes were observed for LRCCs versus CCPs: (1) postoperative diabetes insipidus: 6/20 (30%) versus 17/25 (68%) (p = .006); and (2) posttreatment recurrence: 2/20 (10%) versus 10/25 (40%) (p = .025). The following MR findings were observed for LRCCs versus CCPs: (1) solid component: 7/20 (35%) versus 21/25 (84%) (p = .001); (2) thick cyst wall: 2/20 (10%) versus 12/25 (48%) (p = .009); (3) intracystic septation: 1/20 (5%) versus 8/25 (32%) (p = .030); (4) snowman shape: 18/20 (90%) versus 1/25 (4%) (p < .001); (5) off-midline extension: 0/0 (0%) versus 10/25 (40%) (p = .001); and (6) oblique angle of the sagittal long axis of the tumor: 89.9° versus 107.1° (p = .001).

CONCLUSIONS

LRCCs can be differentiated from CCPs based on their clinical and imaging findings, especially their specific anatomical growth patterns. We suggest using the pretreatment diagnosis to select the appropriate surgical approach and thus improve the clinical outcome.

Neoplasms and tumor-like lesions of the sellar region: imaging findings with correlation to pathology and 2021 WHO classification

The sellar region represents a complex anatomical area, composed of multiple structures of different embryological derivation, including the skull base and the pituitary gland, along with vascular, nervous, and meningeal structures. Masses arising in this region include benign and malignant lesions arising from the pituitary gland itself, but also from vestigial embryological residues or surrounding tissues, that may require different therapeutic approaches. While assessing sellar region masses, the combination of clinical presentation and imaging features is fundamental to define hypotheses about their nature. MR represents the imaging modality of choice, providing information about the site of the lesion, its imaging features, and relation with adjacent structures, while CT is useful to confirm the presence of lesion calcifications or to reveal tumor invasion of bony structures. The aim of this pictorial review is to provide an overview of the common neoplasms and tumor-like conditions of the sellar region, according to the 2021 WHO Classification of Tumors of the Central Nervous System (fifth edition), with an emphasis on the radiologic-pathologic correlation. After a brief introduction on the anatomy of this region and the imaging and pathological techniques currently used, the most relevant MRI characteristics, clinical findings, and pathological data, including histologic and molecular features, will be shown and discussed, with the aim of facilitating an appropriate differential diagnosis among these entities.

Imaging of pituitary tumors: an update with the 5th WHO Classifications-part 2. Neoplasms other than PitNET and tumor-mimicking lesions

Many types of tumors can develop in the pituitary gland. In the recently revised 5th editions of the World Health Organization (WHO) classifications (2021 WHO Classification of Central Nervous System Tumors and the 2022 WHO Classification of Endocrine and Neuroendocrine Tumors), various changes have been made to the tumors other than pituitary neuroendocrine tumor (PitNET)/pituitary adenoma, as well as PitNET. Adamantinomatous craniopharyngioma and papillary craniopharyngioma are now considered separate tumors in the 5th edition of the WHO classification. Tumors positive for thyroid transcription factor 1, a marker of posterior pituitary cells, are now grouped together in the pituicyte tumor family in the 5th edition of the WHO classification of Endocrine and Neuroendocrine Tumors. Poorly differentiated chordoma is newly listed in the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. In this paper, we present the latest WHO classification of pituitary tumors (adamantinomatous craniopharyngioma, papillary craniopharyngioma, pituitary blastoma, pituicyte tumor family, tumors of pituitary origin other than those of the pituicyte tumor family, germinoma, meningioma, chordoma, metastatic tumors, lymphoma, and pituitary incidentaloma), review diseases requiring differentiation from tumors (pituitary abscess, hypophysitis, pituitary hyperplasia, Rathke's cleft cyst, arachnoid cyst, and aneurysm), and discuss diagnoses based on imaging findings.

Imaging of pituitary tumors: an update with the 5th WHO Classifications-part 1. Pituitary neuroendocrine tumor (PitNET)/pituitary adenoma

The pituitary gland is the body's master gland of the endocrine glands. Although it is a small organ, many types of tumors can develop within it. The recently revised fifth edition of the World Health Organization (WHO) classifications (2021 World Health Organization Classification of Central Nervous System Tumors and 2022 World Health Organization Classification of Endocrine and Neuroendocrine Tumors) revealed significant changes to the classification of pituitary adenomas, the most common type of pituitary gland tumor. This change categorized pituitary adenomas as neuroendocrine tumors and proposed the name to be revised to pituitary neuroendocrine tumor (PitNET). The International Classification of Diseases for Oncology behavior code for this tumor was previously "0" for benign tumor. In contrast, the fifth edition WHO classification has changed this code to "3" for primary malignant tumors as same to neuroendocrine tumor in other organs. Because the WHO classification made an important and significant change in the fundamental concept of the disease, in this paper, we will discuss the imaging diagnosis (magnetic resonance imaging, computed tomography, and positron emission tomography) of PitNET/pituitary adenoma in detail, considering these revisions as per the latest version of the WHO classification.

Different Faces of Rathke's Cleft Cyst

Rathke's cleft cysts (RCC) are rare benign cystic lesions that might present with different imaging features, potentially posing a problem in the radiological diagnosis of cystic sellar lesions. The purpose of this pictorial review is to present an overview of the radioclinical features of RCC through four clinical cases with different radiologic findings confirmed by pathology, as well as reviewing the common differential diagnosis to be considered. The subjects are women, aged 11 to 73 who underwent recent transsphenoidal surgical resection with a postoperative follow-up period of a few months to three years.

Stereotactic radiosurgery for Rathke's cleft cysts: an international multicenter study

OBJECTIVE

Rathke's cleft cysts (RCCs) are sellar collections from an incompletely regressed Rathke's pouch. Common symptoms of RCCs can include headaches, visual loss, and endocrinopathy. Surgery is required in some cases of symptomatic or growing RCCs. Recurrence after surgery is common (range 10%-40%). Stereotactic radiosurgery (SRS) has been used in an attempt to control growth and symptoms, but outcomes are not well known. The authors sought to study the outcomes of RCCs following Gamma Knife surgery for both salvage and initial treatment.

METHODS

The outcomes of 25 patients with RCCs who underwent SRS between 2001 and 2020 were reviewed. Four patients received initial SRS and 21 were treated with salvage SRS. Diagnosis was based on imaging or histopathology. Cyst control was defined as stability or regression of the cyst. Kaplan-Meier analysis was used to determine time to recurrence and determine potential factors for recurrence.

RESULTS

The respective median clinical follow-up and margin dose were 6.5 years and 12 Gy. Overall control was achieved in 19 (76%) of 25 patients, and 4 recurrences required further intervention. The average time to recurrence was 35.6 months in those RCCs that recurred. Visual recovery occurred in 14 (93.3%) of 15 patients and no new post-SRS visual deficits occurred. The presence of a pretreatment visual deficit was often an indicator of RCC regrowth. All 3 patients with pretreatment hyperprolactinemia experienced resolution after SRS. New endocrinopathy related to SRS was noted in 5 (20%) of 25 patients, all of which were thyroid and/or cortisol axis related. Upfront SRS was used in 4 patients. No new endocrinopathies or visual deficits developed after upfront SRS, and the 1 patient with a pretreatment visual deficit recovered. One of the 4 patients with upfront SRS experienced a recurrence after 7.5 years.

CONCLUSIONS

SRS produced effective recovery of visual deficits and carries a low risk for new visual deficits. Cyst control was achieved in approximately three-fourths of the patients. Following SRS, patients without pretreatment visual deficits are less likely to have RCC regrowth. Endocrinopathy can occur after SRS, similar to other sellar mass lesions. Initial SRS shows the potential for long-term cyst control, with improvement of symptoms and a low risk for complications.

Rathke’s cleft cysts: A single-center case series

Background:

Rathke’s cleft cysts (RCCs) are common benign sellar or suprasellar lesions. The aim of this study is to report our experience on the management of 27 RCC cases.

Methods:

We retrospectively analyzed a series of 27 patients with symptomatic RCC who were referred to our department between January 2016 and January 2020. Data regarding patients’ demographics, clinical evaluations, laboratory and neuroimaging findings, pathologic records, surgical treatment, and complications were extracted from our electronic database. All patients underwent RCC removal through a direct endoscopic endonasal transsphenoidal (EETS) approach, except for two cases.

Results:

Data of 27 patients (3 men and 24 women; mean age: 38 years) with symptomatic RCC were reviewed. The most common presenting symptom was headache, occurring in 20 (74.0%) patients. In 16 (59.2%) cases, the tumor was primarily located in the sella turcica. Nine (33.3%) cases exhibited a secondary suprasellar extension.

Conclusion:

Our experience with RCC patients showed that EETS is a safe method of treatment, with minimal recurrence.

Xanthogranuloma of the Sellar Region: A Comprehensive Review of Neuroimaging in a Rare Inflammatory Entity

Xanthogranuloma of the sellar region is a rare chronic inflammatory lesion resulting from secondary hemorrhage, inflammation, infarction, and necrosis of an existing Rathke’s cleft cyst, craniopharyngioma, or pituitary adenoma. Sellar xanthogranulomas are challenging to differentiate from other cystic lesions preoperatively due to the lack of characteristic imaging features. We performed a literature overview of the clinical and paraclinical features, treatment options, and long-term outcomes of patients with sellar xanthogranuloma, focusing on the preoperative radiological diagnosis. The hyperintense signal in both T1- and T2-weighted sequences, cystic or partially cystic morphology, ovoid shape, sellar epicenter, intra- and suprasellar location, intratumoral calcifications, linear rim contrast enhancement, and the absence of cavernous sinus invasion suggest xanthogranuloma in the preoperative differential diagnosis. An endoscopic endonasal gross total resection without radiotherapy is the preferred first-line treatment. Given the low rate of recurrence rate and low chance of endocrinological recovery, a mass reduction with decompression of the optic apparatus may represent an appropriate surgical goal. Identifying the xanthogranulomas’ mutational profile could complement histopathological diagnosis and give insight into their histo-pathogenesis. A better preoperative neuroimagistic diagnosis of sellar xanthogranulomas and differentiation from lesions with a poorer prognosis, such as craniopharyngioma, would result in an optimal personalized surgical approach.

Approach to the Patient: Differential Diagnosis of Cystic Sellar Lesions

Cystic lesions arising in the sellar region are not uncommon and encompass cystic pituitary adenomas, Rathke cleft cysts, craniopharyngiomas, and arachnoid cysts. Their clinical presentation may be similar, including headache, visual field defects, and anterior pituitary hormone deficits, which makes differential diagnosis challenging. On the other hand, imaging features may indicate certain pathologies. In this approach to the patient, we describe the case of a patient who presented with right temporal hemianopsia and a sellar/suprasellar cystic lesion, which was determined to be Rathke cleft cyst. We discuss the imaging characteristics that may suggest a particular diagnosis between Rathke cleft cyst, cystic pituitary adenoma, craniopharyngioma, and arachnoid cyst and propose a flowchart for aiding in the imaging differential diagnosis.

A study on clinical outcomes of Rathke's cleft cyst in patients managed conservatively

OBJECTIVES

The primary objective was to investigate the clinical presentation, hormonal dysfunction, imaging characteristics and natural history of RCCs that were managed conservatively. Secondary objective was to identify factors associated with cyst progression.

METHODS

A retrospective review of patients with the clinical diagnosis of RCC-identified from word search from radiology reports that were followed up from January 1999 to March 2019 was performed. The demographics, clinical data, radiological features and outcomes were reviewed and analyzed.

RESULTS

105 patients were identified with a median follow up of 6 years. 68 patients (64.8%) were managed conservatively from diagnosis till last follow up while 37 patients (35.2%) underwent surgery, with 26 operated at time of diagnosis and 11 operated upon monitoring. For patients managed conservatively from diagnosis till last follow up, incidental finding was the most common presentation. 19.1% had either one or more axes of hormonal dysfunction, with hypogonadism and hypocortisolemia being the commonest ones. Imaging features were variable. 66.2% of patients had T2W hyperintensity on MRI. Pathognomonic feature of intracystic nodule was present in only 14.7% of patients. Among the 79 patients with repeated MRI imaging (68 from conservative group and 11 from surgical group), 32.9% of patients developed cyst progression while 67.1% had either static disease or regression in size of RCC. Median time to progression of cyst was 14 months. Longer median follow up duration and presence of pituitary stalk displacement at presentation were associated with cyst progression. Only one patient developed new endocrine dysfunction.

CONCLUSION

2/3 of the RCCs had static disease or even regression in the size of the cyst. They rarely gave rise to additional endocrine dysfunction by adopting observant approach. Cyst progression was demonstrated in 1/3 of patients. Conservative treatment remained a reasonable treatment for patients without significant symptoms.

Central Diabetes Insipidus after Syndrome of Inappropriate Antidiuretic Hormone Secretion with Severe Hyponatremia in a Patient with Rathke's Cleft Cyst

A 49-year-old man developed severe hyponatremia associated with transient headache and was diagnosed with syndrome of inappropriate antidiuretic hormone secretion (SIADH). Fluid restriction and sodium supplementation corrected the hyponatremia. However, several days later, the patient exhibited hypernatremia with thirst and polyuria. A detailed examination indicated central diabetes insipidus (CDI) with an intrasellar cystic lesion indicative of Rathke's cleft cyst (RCC). A case of RCC exhibiting headache, hyponatremia, and subsequent hypernatremia has been reported. Our case shows that CDI may appear after SIADH in patients with RCC, especially in those with serum sodium levels that unexpectedly increase rapidly beyond the reference range.

Cyst Type Differentiates Rathke Cleft Cysts From Cystic Pituitary Adenomas

Purpose

A classification system for cystic sellar lesions does not exist. We propose a novel classification scheme for these lesions based on the heterogeneity of the cyst wall/contents and the presence of a solid component on imaging.

Methods

We retrospectively reviewed 205 patients’ medical records (2008–2020) who underwent primary surgery for a cystic sellar lesion. Cysts were classified a priori into 1 of 4 cyst types based on the heterogeneity of the cyst wall/contents and the presence of a solid component imaging. There was high interrater reliability. Univariable and multivariable models were used to estimate the ability of cyst type to predict the two most common diagnoses: Rathke cleft cyst (RCC) and cystic pituitary adenoma.

Results

The frequencies of RCC and cystic pituitary adenoma in our cohort were 45.4% and 36.4%, respectively. Non-neoplastic lesions (e.g., arachnoid cysts and RCC) were more likely to be Type 1 or 2, whereas cystic neoplasms (e.g., pituitary adenomas and craniopharyngiomas) were more likely to be Type 3 or 4 (p<0.0001). Higher cyst types, compared to Type 1, had higher odds of being cystic pituitary adenomas compared to RCCs (OR: 23.7, p=0.033, and 342.6, p <0.0001, for Types 2 and 4, respectively). Lesions with a fluid-fluid level on preoperative MRI also had higher odds of being pituitary adenomas (OR: 12.7; p=0.023). Cystic pituitary adenomas were more common in patients with obesity (OR: 5.0, p=0.003) or symptomatic hyperprolactinemia (OR: 11.5; p<0.001, respectively). The multivariable model had a positive predictive value of 82.2% and negative predictive value of 86.4%.

Conclusion

When applied to the diagnosis of RCC versus cystic pituitary adenoma, higher cystic lesion types (Type 2 & 4), presence of fluid-fluid level, symptomatic hyperprolactinemia, and obesity were predictors of cystic pituitary adenoma. Further validation is needed, but this classification scheme may prove to be a useful tool for the management of patients with common sellar pathology.

Added Value of Contrast-enhanced 3D-FLAIR MR Imaging for Differentiating Cystic Pituitary Adenoma from Rathke's Cleft Cyst

PURPOSE

Half of the surgically proven Rathke's cleft cysts (RCCs) can be preoperatively misdiagnosed as cystic pituitary adenoma (CPA). We aimed to evaluate the usefulness of contrast-enhanced (CE) 3D T2 fluid-attenuated inversion-recovery (3D T2-FLAIR) imaging for differentiating between CPA and RCC.

METHODS

This retrospective study included six patients with RCC (all pathologically confirmed) and six patients with CPA (five pathologically confirmed, one clinically diagnosed). The 12 patients underwent pre- and post-contrast T1-weighted (T1W)- and 3D T2-FLAIR imaging at 3T. Based on the degree of enhancement of the lesion wall, two radiologists independently scored the images using a 3-point grading system. Interobserver agreement was calculated by using the κ coefficient. The statistical significance of grading differences was analyzed with the Mann-Whitney U-test. Another neuroradiologist first interpreted conventional MR images (1st session), and then the reader read images to which the 3D T2-FLAIR images had been added (2nd session). Sensitivity, specificity, and accuracy of the reader's interpretation were calculated.

RESULTS

Interobserver agreement for post-contrast T1W- and 3D T2-FLAIR images was excellent (κ = 1.000 and 0.885, respectively). Although the mean enhancement grade on post-contrast T1W images of RCCs and CPAs was not significantly different, on post-contrast 3D T2-FLAIR images it was significantly higher for RCCs and CPAs (P < 0.05). Three CPAs (50%) showed remarkable, donut-like enhancement along the inner margin of the cyst on CE-3D T2-FLAIR images; this was not the case on CE-T1W images. The sensitivity, specificity, and accuracy of the 2nd session were 1.00, 0.83, and 0.92, respectively, which were improved compared to the 1st session (1.00, 0.50, and 0.75, respectively).

CONCLUSION

CE-3D FLAIR imaging is useful for discriminating CPAs and RCCs.

Primary Tumors of the Pituitary Gland: Radiologic-Pathologic Correlation

Primary tumors of the pituitary gland are the second most common histologic category of primary central nervous system tumors across all age groups and are the most common in adolescents to young adults, despite originating from a diminutive endocrine gland that is often described as "about the size of a pea." The vast majority of these represent primary tumors of the adenohypophysis, specifically pituitary adenomas, which can be either functional or silent with regard to hormone hypersecretion. According to the fourth edition of the World Health Organization classification of endocrine tumors, published in 2017, cellular lineage and immunohistochemical stains for pituitary hormones and/or transcription factors help with making the correct pathologic diagnosis. From a radiologic standpoint, microadenomas pose challenges for accurate detection and avoiding false-negative or false-positive results, while macroadenomas pose challenges from local mass effect on surrounding structures. Pituitary carcinoma and pituitary blastoma also arise from the adenohypophysis and are characterized by metastatic disease and infantile presentation, respectively. While primary tumors of the adenohypophysis are common, a second category comprising primary tumors of the Rathke pouch (ie, craniopharyngioma) are uncommon, and a third category comprising primary tumors of the neurohypophysis (eg, pituicytoma) are rare. The authors review all three categories of pituitary tumors, with emphasis on radiologic-pathologic correlation, including the typical neuroimaging, histologic, and molecular features that may point toward a specific diagnosis. Work of the U.S. Government published under an exclusive license with the RSNA.

A diagnostic tree for differentiation of adult pilocytic astrocytomas from high-grade gliomas

BACKGROUND

To develop a diagnostic tree analysis (DTA) model based on demographical information and conventional MRI for differential diagnosis of adult pilocytic astrocytomas (PAs) and high-grade gliomas (HGGs; World Health Organization grade III-IV).

METHODS

A total of 357 adult patients with pathologically confirmed PA (n = 65) and HGGs (n = 292) who underwent conventional MRI were included. The patients were randomly divided into training (n = 250) and validation (n = 107) datasets to assess the diagnostic performance of the DTA model. The DTA model was created using a classification and regression tree algorithm on the basis of demographical and MRI findings.

RESULTS

In the DTA model, tumor location (on cerebellum, brainstem, hypothalamus, optic nerve, or ventricle), cystic mass with mural nodule appearance, presence of infiltrative growth, and major axis (cutoff value, 2.9 cm) were significant predictors for differential diagnosis of adult PAs and HGGs. The AUC, accuracy, sensitivity, and specificity were 0.94 (95% confidence interval 0.86-1.00), 96.2%, 89.5%, and 97.7%, respectively, in the test set. The accuracy of the DTA model was significantly higher than the no-information rate in the test (96.2 % vs 85.0%, P < 0.001) set.

CONCLUSION

The DTA model based on MRI findings may be useful for differential diagnosis of adult PA and HGGs.

Anterior pituitary function in Rathke's cleft cysts versus nonfunctioning pituitary adenomas

Although Rathke's cleft cysts (RCCs) are common sellar/parasellar lesions, studies examining pituitary function in patients with nonsurgical RCC are limited. This study aimed to clarify the importance of RCCs, including small nonsurgical ones, as a cause of hypopituitarism by determining the prevalence of pituitary hormone secretion impairment and its relationship to cyst/tumor size in patients with RCC and in those with nonfunctioning pituitary adenoma (NFA). We retrospectively investigated the basal levels of each anterior pituitary hormone, its responses in the stimulation test(s), and cyst/tumor size in patients with RCC (n = 67) and NFA (n = 111) who were consecutively admitted to our hospital for endocrinological evaluation. RCCs were much smaller than NFAs (median height, 12 vs. 26 mm). The prevalence of gonadotropin, PRL, and GH secretion impairment in RCC was lower in comparison to NFA (19% vs. 44%, 34% vs. 61%, and 24% vs. 46%, respectively), whereas the prevalence of TSH and ACTH secretion impairment was comparable (21-27% and 17-24%, respectively). A significant positive relationship between cyst/tumor size and number of impaired hormones was observed in both groups, but smaller cysts could cause hormone secretion impairment in RCC. Stimulation tests suggested that most hormone secretion impairment was attributable to the interrupted hypothalamic-pituitary axis in both groups. Therefore, RCC, even small ones, can cause pituitary dysfunction. Different mechanisms may underlie hypothalamic-pituitary interruption in RCC and NFA.

MR-Based Radiomics for Differential Diagnosis between Cystic Pituitary Adenoma and Rathke Cleft Cyst

Background

It is often tricky to differentiate cystic pituitary adenoma from Rathke cleft cyst with visual inspection because of similar MRI presentations between them. We aimed to design an MR-based radiomics model for improving differential diagnosis between them.

Methods

Conventional diagnostic MRI data (T1-,T2-, and postcontrast T1-weighted MR images) were obtained from 215 pathologically confirmed patients (105 cases with cystic pituitary adenoma and the other 110 cases with Rathke cleft cyst) and were divided into training (n = 172) and test sets (n = 43). MRI radiomics features were extracted from the imaging data, and semantic imaging features (n = 15) were visually estimated by two radiologists. Four classifiers were used to construct radiomics models through 5-fold crossvalidation after feature selection with least absolute shrinkage and selection operator. An integrated model by combining radiomics and semantic features was further constructed. The diagnostic performance was validated in the test set. Receiver operating characteristic curve was used to evaluate and compare the performance of the models at the background of diagnostic performance by radiologist.

Results

In test set, the combined radiomics and semantic model using ANN classifier obtained the best classification performance with an AUC of 0.848 (95% CI: 0.750-0.946), accuracy of 76.7% (95% CI: 64.1-89.4%), sensitivity of 73.9% (95% CI: 56.0-91.9%), and specificity of 80.0% (95% CI: 62.5-97.5%) and performed better than multiparametric model (AUC = 0.792, 95% CI: 0.674-0.910) or semantic model (AUC = 0.823, 95% CI: 0.705-0.941). The two radiologists had an accuracy of 69.8% and 74.4%, respectively, sensitivity of 69.6% and 73.9%, and specificity of 70.0% and 75.0%.

Conclusions

The MR-based radiomics model had technical feasibility and good diagnostic performance in the differential diagnosis between cystic pituitary adenoma and Rathke cleft cyst.

Pituitary apoplexy without chiasm compression: A case report

The present report presents a rare case in which a patient with pituitary apoplexy (PA) without compression of the optic chiasm experienced diagnosable visual impairment in the ensuing months. Endocrinologically, the condition was a prolactinoma followed by bleeding into the pituitary gland. Due to the unexplained functional changes in the patient, an electrophysiological examination (pattern electroretinogram and pattern visual evoked potentials) was performed, which verified a bilateral non-inflammatory neurogenic lesion. This finding was confirmed by functional magnetic resonance imaging (fMRI) examination. Structural MRI did not reveal chiasm compression in the time sequence or alteration of the optic nerves (the diameter of the optic nerve at different distances from the eye and the diameter of the optic nerve sheath at different distances from the eye). Similarly, neither the retinal nerve fiber layer (RNFL) nor the vessel density was altered. The present report suggests that changes in visual fields may be due to ischemia in the area of the chiasm and optic nerves, similar to PA.

Imaging of the sellar and parasellar regions

Although a wide variety of pathologies can occur in the limited anatomic space within and surrounding the sella turcica only a few are common. This review aims to briefly summarize pituitary and parasellar anatomy and provide a focused description of the imaging features of both common and rare pituitary pathologies. Diagnoses of imaging findings with important implications for clinical management are highlighted. MR is the primary diagnostic modality for evaluation of this anatomic region. CT supplements MR in the evaluation of pathologies involving the bony sella turcica while angiography or nuclear medicine plays a limited clinical role. Despite the wide array of pathologies, imaging and basic clinical history will frequently yield a specific diagnosis or narrow differential. In certain pathologies such as hypophysitis or pituitary hyperplasia, proper imaging interpretation may obviate the need for surgical biopsy or resection. The two key elements to diagnosis in the pituitary region are localization of the abnormality and recognition of characteristic imaging features for different pathologies. Localization is particularly important in separating parasellar masses such as meningiomas, skull base tumors, carotid aneurysms, craniopharyngiomas, or sphenoid sinus tumors from pituitary masses. Imaging features are often variable and in some cases such as craniopharyngioma or epidermoid, can be almost pathognomonic. In cases of neoplastic pathology, imaging both provides diagnostic information and guides planning of surgical biopsy or resection. In most cases, biopsy or resection is performed though a trans-sphenoidal endoscopic route, and identifying invasion or the suprasellar cistern, skull base, or cavernous sinuses is critical.

Pituitary incidentalomas in paediatric population: Incidence and characteristics

OBJECTIVE

To determine the incidence of pituitary incidentalomas in the paediatric population and among its different age subgroups as well as to identify the characteristics of these lesions. Additionally, we aim to give a perspective on the management and follow-up of these patients.

DESIGN AND PATIENTS

We retrospectively studied MRI of children aged 18 years or below who underwent MRI with sellar region within their field of view between January 2010 and December 2018.

MEASUREMENTS

Pituitary lesions were considered incidental according to the definition by the Endocrine Society. We reported the size, location and signal characteristics of each lesion. Medical charts of the subjects were reviewed for age, sex, the MRI indication and the hormonal assays levels.

RESULTS

We identified 40 pituitary lesions of which 31 were incidental lesions. The incidence of pituitary incidentaloma in our cohort was 22 per 1000 patients with female predisposition ( 64.5%) and a mean age of 11 ± 6 years. Rathke's cleft cyst was the most prevalent lesion, accounting for 67.7% followed by cystic pituitary lesions and microadenomas. The most common indications for imaging were growth disturbance (12.9%) followed by headache (9.7%). Abnormal laboratory workup was present in 13% of the subjects. Incidental lesions were more common in the older age groups compared to young children.

CONCLUSION

Incidental pituitary lesions in the paediatric population are relatively infrequent and increases with age. Rathke's cleft cyst is the most common incidentally encountered pituitary lesion followed by cystic pituitary lesions and microadenomas.

Magnetic resonance imaging of the hypothalamo-pituitary region

The diagnosis and management of mass lesions in the sellar and parasellar areas remain challenging. When approaching patients with possible sellar or hypothalamic masses, it is important not only to focus on imaging but also detect possible pituitary hormone deficits or excess, in order to establish an appropriate diagnosis and initiate treatment. The imaging modalities used to characterize hypothalamic and pituitary lesions have significantly evolved over the course of the past several years. Computed tomography (CT) and CT angiography play a major role in detecting various sellar lesions, especially in patients who have contraindications to magnetic resonance imaging (MRI) and can also yield important information for surgical planning. However, MRI has become the gold standard for the detection and characterization of hypothalamic and pituitary tumors, infections, cystic, or vascular lesions. Indeed, the imaging characteristics of hypothalamic and sellar lesions can help narrow down the differential diagnosis preoperatively. In addition, MRI can help establish the relationship of mass lesions to surrounding structures. A pituitary MRI examination should be obtained if there is concern for mass effect (including visual loss, ophthalmoplegia, headache) or if there is clinical suspicion and laboratory evidence of either hypopituitarism or pituitary hormone excess. The information obtained from MRI images also provides us with assistance in planning surgery. Using intraoperative MRI can be very helpful in assessing the adequacy of tumor resection. In addition, MRI images yield reliable data that allow for noninvasive monitoring of patients postoperatively.

Neuroimaging of central diabetes insipidus

Central diabetes insipidus (CDI) occurs secondary to deficient synthesis or secretion of arginine vasopressin peptide from the hypothalamo-neurohypophyseal system (HNS). It is characterized by polydipsia and polyuria (urine output >30mL/kg/day in adults and >2l/m²/24h in children) of dilute urine (<250mOsm/L). It can result from any pathology affecting one or more components of the HNS including the hypothalamic osmoreceptors, supraoptic or paraventricular nuclei, and median eminence of the hypothalamus, infundibulum, stalk or the posterior pituitary gland. MRI is the imaging modality of choice for evaluation of the hypothalamic-pituitary axis (HPA), and a dedicated pituitary or sella protocol is essential. CT can provide complimentary diagnostic information and is also of value when MRI is contraindicated. The most common causes are benign or malignant neoplasia of the HPA (25%), surgery (20%), and head trauma (16%). No cause is identified in up to 30% of cases, classified as idiopathic CDI. Knowledge of the anatomy and physiology of the HNS is crucial when evaluating a patient with CDI. Establishing the etiology of CDI with MRI in combination with clinical and biochemical assessment facilitates appropriate targeted treatment. This chapter illustrates the wide variety of causes and imaging correlates of CDI on neuroimaging, discusses the optimal imaging protocols, and revises the detailed neuroanatomy required to interpret these studies.

Ophthalmic Manifestations of Rathke's Cleft Cyst and Its Association to Radiological Characteristics

PURPOSE

To evaluate the ophthalmic features of Rathke's cleft cyst (RCC) and its association with radiological characteristics.

METHODS

In this retrospective single-center study, patients who showed typical findings suggestive of RCC on magnetic resonance imaging (MRI) and underwent relevant ophthalmic examination were recruited retrospectively. Patients were stratified into two groups according to the presence or absence of ophthalmic symptoms related to RCC. We reviewed patients' demographic information, initial symptoms, endocrinological status, ophthalmic features, and characteristics of MRI. Height, size and location of RCC, as well as the optic chiasm displacement assessed from MRI.

RESULTS

Thirty-three patients (20 women and 13 men) were included in this study from among 335 patients with RCC on MRI. Fifteen patients had ophthalmic manifestation related to the cyst (Ophthalmic group), whereas 18 patients were not (Non-ophthalmic group). Headache was the most common initial symptom (15 patients, 45.5%), followed by visual disturbance (7, 21.2%), diplopia (1, 3.0%), retro-orbital pain (1, 3.0%), galactorrhea (1, 3.0%), and peripheral extremity discomfort (1, 3.0%). In seven asymptomatic patients (21.2%), the lesion was an incidental finding during a regular medical examination. Ophthalmic manifestation included visual field defect (14 patients, 93.3%) and diplopia (1 patient, 6.7%). The height, volume, and the coronal and sagittal displacements were larger in the ophthalmic group (P < .001, all). Eleven patients who manifested ophthalmic symptoms underwent excision surgeries and nine of them (81.8%) experienced visual function improvement.

CONCLUSION

Appropriate ophthalmic examinations are warranted in patients with RCC, and treatment should be actively considered in patients with ophthalmic manifestations.

Outcome of nonneoplastic pituitary cysts during conservative monitoring and after surgery-a SwissPit study

BACKGROUND

Nonneoplastic cysts of the pituitary are common incidental findings; however, best management remains controversial as they are often asymptomatic but eventually may cause symptoms. The aims of this study are to describe the course of conservative and surgical approaches, to assess timing and results of surgery, and to identify predictors for growth.

METHODS

This retrospective study reviewed medical records from the Swiss Pituitary registry. Fifty patients (68% females; median 44 years old) fulfilled the criteria for inclusion. Three cohorts were defined: a conservative group (n = 28), a group who initially needed surgery (n = 18), and a group who had surgery during follow-up (n = 4). Transsphenoidal cyst evacuation was used in 95%; 68% had intraoperative MRI. All patients had standardized neuroradiological, endocrinological, and ophthalmological follow-up (mean 44 (7-151) months).

RESULTS

Conservative follow-up of 30 (6-120) months showed cyst growth in 16% (4%/year) and spontaneous shrinkage in 19% (8%/year). Cyst-volumes changed - 0.95 to 1.45 cm³ per year. The probability of needing surgery was 5% per year. Larger cysts (> 1.4 cm³) and T1-hypo-/T2-hyper cyst contents were associated with higher probability for growth. Postoperatively, no remnant was seen in 82% during a follow-up of 53 months. Visual field deficiencies improved in 83%. Hypopituitarism recovered in up to 88%. But for a smaller complication rate, the outcome was not influenced by the use of the intraoperative MRI.

CONCLUSIONS

Asymptomatic nonneoplastic pituitary cysts may be monitored; many lesions may shrink with time. Larger or T1-hypo-/T2-hyper cysts have higher growth rates. If indicated, surgery for nonneoplastic sellar cysts is a safe and efficient.

A craniopharyngioma in a Wistar rat most likely originated in a Rathke's cleft cyst

We examined a 110-week-old RccHan^TM: WIST Wistar male rat from a carcinogenicity study. No clinical signs were observed, and the rat was sacrificed at the end of the study. Macroscopically, within the midline of the sphenoid bone, was a 10 mm, non-infiltrative, soft, heterogeneous mass. Microscopic evaluation showed an expansile, cystic proliferation, consisting of two patterns of epithelial lining: well-differentiated areas lined by a single layer to a pseudostratified, ciliated-cuboidal epithelia with Goblet cells compatible with Rathke’s cleft cyst; and poorly differentiated ones that formed irregular papillary projections, covered by atypical epithelia with squamous differentiation and hyperkeratosis compatible with areas of craniopharyngioma. Pleomorphisms were high in atypical areas with up to 2–3 mitotic figures per high power field. Within the cystic cavities, there was abrupt keratinization, mucus, cholesterol clefts, and foci of foamy macrophages. Immunohistochemistry revealed strong pancytokeratin immunolabelling of neoplastic cells confirming the epithelial origin. Well-differentiated epithelial lining showed cytokeratin-20 and cytokeratin-8 immunoreactivity, whereas the atypical squamous epithelium presented with a loss of cytokeratin-20 positive signal and weak to moderate positivity with cytokeratin-8. Areas compatible with a Rathke’s cleft cyst and craniopharyngioma were considered to co-exist in the same mass.