Biomarkers of Pineal Region Tumors: A Review

The establishment of machine learning prognostic prediction models for pineal region tumors based on SEER-A multicenter real-world study

BACKGROUND

Pineal region tumors (PRT) are rare intracranial neoplasms with diverse pathological types and growth characteristics, leading to varied clinical manifestations. This study aims to develop machine learning (ML) models for survival prediction, offering valuable insights for medical practice in the management of PRTs.

METHODS

Clinical information on PRTs was extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan-Meier (K-M) analysis was used to analyze the survival of PRT patients. Univariate and multivariate Cox regression analyses were conducted to identify risk factors for the survival of PRT patients. Then, nomograms were constructed. Seven ML models including Decision Tree, Logistic Regression, LightGBM, Random Forest, XGBoost, K-Nearest Neighbor Algorithm (KNN), and Support Vector Machine (SVM), were developed to predict the prognosis of PRT patients. The predictive value of ML models was evaluated by the area under the receiver's operating characteristic curve (AUC-ROC), tenfold cross verification, calibration curve, and decision curve analysis (DCA).

RESULTS

Univariate and multivariate Cox regression revealed that age, histopathology, radiotherapy, and tumor size were independent risk factors for overall survival (OS). Histopathology, surgery, radiotherapy, and tumor size were risk factors for cancer-specific survival (CSS). K-M survival analysis revealed that age, histopathology, marital status, radiotherapy, sex, and surgery significantly impacted OS, while age, histopathology, marital status, race, radiotherapy, sex, and surgery significantly influenced CSS. In the prediction of OS, the ML models with the best clinical utility were RF, Logistic Regression, and XGBoost. For CSS, the most effective models were RF, LightGBM, and RF.

CONCLUSION

ML models demonstrate significant potential and high predictive efficacy in forecasting long-term postoperative survival in PRT patients, providing substantial clinical value.

Pineal parenchymal tumor of intermediate differentiation: Case series and literature review: Is it time for a consensus?

Background

Pineal parenchymal tumor of intermediate differentiation (PPTID) is a rare tumor. This study aims to evaluate patient outcomes and propose a treatment algorithm based on existing literature and our case series.

Methods

This prospective observational study includes seven patients diagnosed with PPTID through histopathology. We analyzed their clinical presentation, magnetic resonance imaging findings, surgical approaches, histopathological and immunohistochemical analysis, adjuvant treatments, and outcomes. We conducted univariate and multivariate statistical analyses.

Results

The mean patient age was 40 years, with a male predominance. All patients presented with hydrocephalus, four of which required cerebrospinal fluid diversion procedures. The average tumor size was 3.13cm, with 85.7% showing brain invasion. Surgical outcomes included one gross total resection, two near total resections, and four subtotal resections. The supracerebellar infratentorial (Krause) approach was used in 71.4% of cases. About 85.7% were diagnosed with grade 3 PPTID. Five patients received adjuvant radiotherapy. The analysis showed each additional mitosis unit decreased survival by 0.17 units, equating to roughly 2 months (P < 0.016). Follow-up ranged from 6 to 120 months, with a 5-year survival rate of 57.1%. Factors influencing survival included the extent of tumor resection, brain invasion, tumor grade, and adjuvant treatment, although it was not statistically significant due to the small sample size.

Conclusion

We propose a treatment algorithm for PPTID and highlight the importance of further research to understand its biological characteristics. Safe maximal resection appears beneficial for higher-grade PPTID, but the role of adjuvant treatment after complete resection of lower-grade tumors remains uncertain.

Plasma miRNA expression profile in pediatric pineal pure germinomas

Background

Pure germinomas account for 40% of pineal tumors and are characterized by the lack of appreciable tumor markers, thus requiring a tumor biopsy for diagnosis. MicroRNAs (miRNA) have emerged as potential non-invasive biomarkers for germ cell tumors and may facilitate the non-invasive diagnosis of pure pineal germinomas.

Material and methods

A retrospective chart review was performed on all patients treated at the Children's Cancer Hospital Egypt diagnosed with a pineal region tumor between June 2013 and March 2021 for whom a research blood sample was available. Plasma samples were profiled for miRNA expression, and DESeq2 was used to compare between pure germinoma and other tumor types. Differentially expressed miRNAs were identified. The area under the curve of the receive;r operating characteristic curve was constructed to evaluate diagnostic performance.

Results

Samples from 39 pediatric patients were available consisting of 12 pure germinomas and 27 pineal region tumors of other pathologies, including pineal origin tumors [n = 17; pineoblastoma (n = 13) and pineal parenchymal tumors of intermediate differentiation (n = 4)] and others [n = 10; low-grade glioma (n = 6) and atypical teratoid rhabdoid tumor (n = 4)]. Using an adjusted p-value <0.05, three miRNAs showed differential expression (miR-143-3p, miR-320c, miR-320d; adjusted p = 0.0058, p = 0.0478, and p = 0.0366, respectively) and good discriminatory power between the two groups (AUC 90.7%, p < 0.001) with a sensitivity of 25% and a specificity of 100%.

Conclusion

Our results suggest that a three-plasma miRNA signature has the potential to non-invasively identify pineal body pure germinomas which may allow selected patients to avoid the potential surgical complications.

Epidemiological Characteristics and Prognosis Model of Pineal Region Tumors: A Retrospective Analysis Based on the SEER Database

BACKGROUND

A pineal region tumor is a rare intracranial tumor, and its specific location leads to its own characteristics. This study aimed to provide some insight for medical practice in the care of pineal region tumors. We investigated the key epidemiological characteristics and survival prognosis of pineal tumors based on the epidemiological data from the Surveillance, Epidemiology, and End Results database.

METHODS

Data of pineal region tumor patients from 1975 to 2019 were extracted from the Surveillance, Epidemiology, and End Results database. The data were divided into 3 pathologic groups: germ cell tumors, pineal parenchymal tumors, and other. The patients' overall survival (OS) was analyzed using the Kaplan-Meier method. The prognostic effects of the patient characteristics on OS were explored using the Cox proportional hazard model. The analysis results are presented as tabular data, Kaplan-Meier plots, forest plots, and nomograms. A calibration curve was used to verify the nomograms. All analyses were performed for all patients overall and stratified by pathological group using SPSS and R language.

RESULTS

Based on the predefined inclusion and exclusion criteria, 628 patients were included in this study, of whom 440 (70.1%) were male and 188 (29.9%) were female. Most patients were aged 0-19 years. The pathological type was germinoma for 225 patients (35.8%). Age, surgery, behavioral code, and pathology were significant factors for OS. A calibration curve was used to verify that the nomograms had a good prediction effect.

CONCLUSIONS

An intuitive nomogram was developed and verified and can predict the prognosis of patients with pineal tumors.

Adding Value to Liquid Biopsy for Brain Tumors: The Role of Imaging

Clinical management in neuro-oncology has changed to an integrative approach that incorporates molecular profiles alongside histopathology and imaging findings. While the World Health Organization (WHO) guideline recommends the genotyping of informative alterations as a routine clinical practice for central nervous system (CNS) tumors, the acquisition of tumor tissue in the CNS is invasive and not always possible. Liquid biopsy is a non-invasive approach that provides the opportunity to capture the complex molecular heterogeneity of the whole tumor through the detection of circulating tumor biomarkers in body fluids, such as blood or cerebrospinal fluid (CSF). Despite all of the advantages, the low abundance of tumor-derived biomarkers, particularly in CNS tumors, as well as their short half-life has limited the application of liquid biopsy in clinical practice. Thus, it is crucial to identify the factors associated with the presence of these biomarkers and explore possible strategies that can increase the shedding of these tumoral components into biological fluids. In this review, we first describe the clinical applications of liquid biopsy in CNS tumors, including its roles in the early detection of recurrence and monitoring of treatment response. We then discuss the utilization of imaging in identifying the factors that affect the detection of circulating biomarkers as well as how image-guided interventions such as focused ultrasound can help enhance the presence of tumor biomarkers through blood-brain barrier (BBB) disruption.

Pediatric pineal region masses: a single-center experience over 25 years

PURPOSE

Pineal region tumors (PRT) represent less than 1% of brain neoplasms. The rare and heterogeneous nature of these tumors is reflected in the variety of treatment modalities employed.

METHODS

A single-center retrospective review of all pediatric patients with pineal region tumors between November 1996 and June 2021 was performed. Fifty-six cases of pineal tumors were reviewed for age and symptoms upon presentation, diagnostic methods, imaging characteristics, histological classification, treatment modalities, recurrence, and mortality rates.

RESULTS

The average age at diagnosis was 11.3 years. The majority of patients were male (82.1%) and Caucasian (73.2%). The most common presenting symptoms were headache (n = 38, 67.9%) and visual problems (n = 34, 60.7%). Hydrocephalus was present in 49 patients (87.5%). Germinoma (n = 20, 35.7%) and non-germinomatous germ cell tumor (NGGCT) (n = 17, 30.4%) were the most common tumors. Chemotherapy was employed for 54 patients (96.4%), radiation for 49 (87.5%), and surgical resection for 14 (25.0%). The average duration of treatment was 5.9 months. Progression-free survival was 74.4% at 5 years and 72.0% at 10 years. Overall survival was 85.7% at 5 years and 77.1% at 10 years.

CONCLUSION

Treatment of pineal region tumors must be targeted to each patient based on presentation, subtype, presence of hydrocephalus, and extent of disease. Upfront surgical resection is usually not indicated. As advances in oncological care proceed, treatment modalities may continue to improve in efficacy.

Neuroimaging of hypophysitis: etiologies and imaging mimics

Hypophysitis is an inflammatory disease affecting the pituitary gland. Hypophysitis can be classified into multiple types depending on the mechanisms (primary or secondary), histology (lymphocytic, granulomatous, xanthomatous, plasmacytic/IgG4 related, necrotizing, or mixed), and anatomy (adenohypophysitis, infundibulo-neurohypophysitis, or panhypophysitis). An appropriate diagnosis is vital for managing these potentially life-threatening conditions. However, physiological morphological alterations, remnants, and neoplastic and non-neoplastic lesions may masquerade as hypophysitis, both clinically and radiologically. Neuroimaging, as well as imaging findings of other sites of the body, plays a pivotal role in diagnosis. In this article, we will review the types of hypophysitis and summarize clinical and imaging features of both hypophysitis and its mimickers.

Temporal profile of serum melatonin levels in paediatric pineal tumours subjected to surgery: newer insights

INTRODUCTION

Pineal tumours (PTs) are rare and histologically variable. Serum melatonin is a well-known product of this gland, albeit with uncertain clinical implications vis-à-vis its utility as a potential tumour marker. In particular, the temporal profile of serum melatonin during the disease course remains unclear and infrequently studied.

METHODS

Ten children with pineal tumours were prospectively studied over 2 years. Midnight serum melatonin levels were estimated before and after surgery (6-week postoperatively) and at the time of clinical-radiological progression. Different clinical, radiological, histological and treatment variables were correlated with the mean change in the pre- and postoperative serum melatonin levels using statistical methods.

RESULTS

Histopathologically, 5 of these cases (50%) were pineal cell tumours, while the rest were tumours of non-pineal cell origin. The mean preoperative serum melatonin level was 94.9 pg/ml (range 20-397 pg/ml), while the mean postoperative level was 69.6 pg/ml (range 45-156 pg/ml; in one case, the levels became non-detectable). Tumour histology (p = 0.04) and gender (p = 0.03) correlated with high preoperative serum levels. While the change in overall mean value did not have any statistical significance (effect size 0.29, p value 0.340), postoperative serum melatonin elevation was significant in tumours of non-pineal cell origin (large effect size 0.93, p value 0.004).

CONCLUSION

The serum melatonin may be affected by age, gender and symptom duration. However, the dynamic of serum melatonin in the perioperative period is largely dependent on the cell of origin of the PT.

The parietooccipital interhemispheric transtentorial approach for pineal tumors

Access to the pineal region has always been a challenge for neurosurgeons. The parietooccipital interhemispheric transtentorial approach is a slight variation of the traditional occipital transtentorial approach that provides adequate exposure to the lesions of the pineal region without introducing additional risks. In this study, the modified parietooccipital interhemispheric transtentorial approach is discussed including step-by-step anatomical cadaveric dissections and operative images. 27 adult patients (age > 18) who were operated over a 30-year period (1992-2022) by the senior author (M.N.P.) at two clinics, Marmara University, Department of Neurosurgery, Istanbul, Turkey and Acibadem Mehmet Ali Aydinlar University, Department of Neurosurgery, Istanbul, Turkey were analyzed. Only pineal region tumors were included in the analysis. Falcotentorial meningiomas and vascular lesions including cavernomas were excluded. 5 cadaveric specimens were dissected step by step following the surgical approach. Each step was documented using a Canon EOS 5D Mark II camera with Canon 100 mm Macro Lens. Step by step images of the dissections were presented including comparison with surgical images. Additional illustrations were used to describe the surgical corridor. The surgical corridor is maintained anterior to the parietooccipital sulcus along the medial of the precuneus. No retraction to the calcarine sulcus resulted in no postoperative hemianopsia. The neurovascular structures along the surgical corridor along with the nuances of the tentorium incision and splenium resection are discussed. The parietooccipital interhemispheric transtentorial approach provides a wide and safe corridor for surgical resection of pineal tumors.

Accuracy of apparent diffusion coefficient values for distinguishing between pineal germ cell tumour and pineoblastoma

AIM

To differentiate between pineal germ cell tumour and pineoblastoma using apparent diffusion coefficient (ADC) values due to their overlapping imaging findings on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

This retrospective study was conducted on 33 patients with pineal germ cell tumours and eight patients with pineoblastoma who underwent pretreatment MRI. Twenty-seven patients (21 with pineal germ cell tumour and six with pineoblastoma) were included for ADC measurement. The minimum and mean ADC values of the tumours were measured, with normalized tumour to control ADC ratios generated. The MRI characteristics of the tumours were evaluated.

RESULTS

The mean and minimum ADC values, normalized mean and minimum ADC ratios of pineal germ cell tumours were significantly higher than those of pineoblastomas (all p<0.005). A cut-off value of 0.92 for the normalized mean ADC ratio was used to distinguish between pineal germ cell tumour and pineoblastoma and achieved an area under the curve of 0.95, sensitivity of 90.5%, specificity of 83.3%, and accuracy of 92.6%. An equal degree of contrast enhancement to the adjacent venous sinus was the only MRI characteristic that suggested the diagnosis of pineal germ cell tumour.

CONCLUSION

The ADC values could help differentiate between pineal germ cell tumour and pineoblastoma, specifically when conventional MRI findings are indeterminate.

Diagnosis and Management of Pineal Germinoma: From Eye to Brain

Pineal germinomas can be very complex in terms of presentation, diagnosis, and management. This review attempts to simplify this complexity in an organized manner, addressing the anatomic relationships that provide the basis for the uniqueness of pineal germinoma. Ocular findings and signs and symptoms of elevated intracranial pressure are the keys to suspecting the diagnosis and obtaining the necessary imaging and cerebrospinal fluid studies. Other symptoms can suggest spread beyond the pineal region. Surgery may only be needed to obtain tissue for a definitive diagnosis, as germinoma is highly responsive to chemotherapy and focused radiation therapy. Hydrocephalus, usually related to tumor obstruction of the cerebral aqueduct, may also need to be addressed. Outcome for pineal germinoma is usually excellent, but relapse can occur and may require additional intervention. These issues are detailed in this review.

A 2-step prediction model for diagnosis of germinomas in the pineal region

Background

Germinomas are sensitive to radiation and chemotherapy, and their management distinctly differs from other kinds of pineal region tumors. The aim of this study was to construct a prediction model based on clinical features and preoperative magnetic resonance (MR) manifestations to achieve noninvasive diagnosis of germinomas in pineal region.

Methods

A total of 126 patients with pineal region tumors were enrolled, including 36 germinomas, 53 nongerminomatous germ cell tumors (NGGCTs), and 37 pineal parenchymal tumors (PPTs). They were divided into a training cohort (n = 90) and a validation cohort (n = 36). Features were extracted from clinical records and conventional MR images. Multivariate analysis was performed to screen for independent predictors to differentiate germ cell tumors (GCTs) and PPTs, germinomas, and NGGCTs, respectively. From this, a 2-step nomogram model was established, with model 1 for discriminating GCTs from PPTs and model 2 for identifying germinomas in GCTs. The model was tested in a validation cohort.

Results

Both model 1 and model 2 yielded good predictive efficacy, with c-indexes of 0.967 and 0.896 for the diagnosis of GCT and germinoma, respectively. Calibration curve, decision curve, and clinical impact curve analysis further confirmed their predictive accuracy and clinical usefulness. The validation cohort achieved areas under the receiver operating curves of 0.885 and 0.926, respectively.

Conclusions

The 2-step model in this study can noninvasively differentiate GCTs from PPTs and further identify germinomas, thus holding potential to facilitate treatment decision-making for pineal region tumors.

PINEAL GERMINOMA PRESENTED WITH PARALYSIS OF UPWARD GAZE AND DIABETES INSIPIDUS

Intracranial germ cell tumors (GCTs) include two categories: germinoma and non germinoma. The pineal gland and suprasellar are the most common site of involvement. The patient is a 14-year-old boy who presented with paralysis of upward gaze, polyuria, polydipsia and diplopia. Examination of vertical eye movements was impaired. Puberty then progressed to stage 3 of Marshall - Tanner and had stopped. In laboratory studies, the patient had anterior hypopituitarism and diabetes insipidus (DI). In pituitary and hypothalamic MRIs, a mass-like enlargement of the pituitary stalk and pineal region was seen, but due to the small size of the lesions, stereotactic biopsy was not possible. During this time, the patient developed recurrent attacks of hydrocephalus. Serum and CSF β-subunit of Human chorionic gonadotropin levels were negative. Treatment was not started because different lesions could cause disease in this area. After one year, a biopsy was performed and the germ cell tumor was diagnosed. Chemotherapy was started and after treatment the vision disorder and diplopia disappeared, but DI and pituitary dysfunction remained. Treatment of intracranial germinoma is multidisciplinary. GCTs are very sensitive to radiation therapy. They are treated with combination of chemotherapy, radiotherapy, surgery, endocrine therapy and have a good prognosis.

Pineal region teratoma with metastases in uncommon locations: a case report

Background

We report a rare case in medical literature of a patient with pineal gland teratoma and uncommon metastases. Usually, metastases of this kind of tumor are located in several organs such as lung and breast, but here we found metastases to the spinal cord and vertebrae.

Case presentation

A 35-year-old Asian white man presented with diplopia and acute neural symptoms in the lower limbs such as numbness, tingling, and paralysis. His medical history was notable for pineal teratoma, treated 1 year previously with surgery, radiotherapy, and chemotherapy. Physical examination of the lower limbs showed absent reflexes and sensation with muscle power scale score of 1 in both limbs. Magnetic resonance imaging of brain and spine revealed many lesions in various locations, most compatible with neural, spinal, and vertebral metastases. Unfortunately, the patient died suddenly before any intervention was carried out.

Conclusion

It is extremely rare for pineal region teratoma to metastasize to the spinal cord and vertebrae, thus more vigilant observation and examination should be provided to patients with pineal teratoma to detect any new lesions and prevent them from becoming dangerous.

Non-invasive preoperative imaging differential diagnosis of pineal region tumor: A novel developed and validated multiparametric MRI-based clinicoradiomic model

BACKGROUND

Preoperative differential diagnosis of pineal region tumor can greatly assist clinical decision-making and avoid economic costs and complications caused by unnecessary radiotherapy or invasive procedures. The present study was performed to pre-operatively distinguish pineal region germinoma and pinealoblastoma using a clinicoradiomic model by incorporating radiomic and clinical features.

METHODS

134 pineal region tumor patients (germinoma, 69; pinealoblastoma, 65) with complete clinic-radiological and histopathological data from Tiantan hospital were retrospectively reviewed and randomly assigned to training and validation sets. Radiomic features were extracted from MR images, then the elastic net and recursive feature elimination algorithms were applied to select radiomic features for constructing a fusion radiomic model. Subsequently, multivariable logistic regression analysis was used to select the clinical features, and a clinicoradiomic model incorporating the fusion radiomic model and selected clinical features was constructed for individual predictions. The calibration, discriminating capacity, and clinical usefulness were also evaluated.

RESULTS

Seven significant radiomic features were selected to construct a fusion radiomic model that achieved an area under the curve (AUC) value of 0.920 and 0.880 in the training and validation sets, respectively. A clinicoradiomic model that incorporated the radiomic model and four selected clinical features was constructed and showed good discrimination and calibration, with an AUC of 0.950 in the training set and 0.940 in the validation set. The analysis of the decision curve showed that the radiomic model and clinicoradiomic model were clinically useful for patients with pineal region tumor.

CONCLUSIONS

Our clinicoradiomic model showed great performance and high sensitivity in the differential diagnosis of germinoma and pinealoblastoma, and could contribute to non-invasive development of individualized diagnosis and treatment of patients with pineal region tumor.

A GIANT GERMINOMA MIMICS HIGH-GRADE GLIOMA: A RARE FORM OF THALAMIC REGION TUMOR

A fourteen-year-old boy initially presented with weakness in the right extremity, worsening in the last three months with stiffness and convulsions in his right extremity. Magnetic resonance imaging of the brain revealed an intra-axial tumor measuring 8.3x7.3x6.8 cm, leading to obstructive hydrocephalus. The patient's condition suddenly worsened with decreased consciousness, and then emergency surgery was performed for tumor resection and external ventricular drainage before switching to a ventriculoperitoneal shunt on the fifth day after surgery. Histopathological examination revealed a germinoma, which is rare in the thalamic region. The patient responded well to radiation therapy after surgery. Ectopic GCT may be difficult to differentiate on radiological examination alone. The current case was initially diagnosed as a high-grade glioma based on radiological findings. A definite diagnosis can be made only after a histopathological examination, which requires a tissue sample. Therefore, many tumors are surgically excised for biopsy purposes A good preoperative examination is very important to determine the approach to patient management. Furthermore, radiotherapy is mandatory for germinoma because of its radiosensitivity.

Molecular Pathology and Targeted Therapies for Personalized Management of Central Nervous System Germinoma

Intracranial germinomas are rare tumours, usually affecting male paediatric patients. They frequently develop in the pineal and suprasellar regions, causing endocrinological disturbances, visual deficits, and increased intracranial pressure. The diagnosis is established on magnetic resonance imaging (MRI), serum and cerebrospinal fluid (CSF) markers, and tumour stereotactic biopsy. Imaging techniques, such as susceptibility-weighted imaging (SWI), T2* (T2-star) gradient echo (GRE) or arterial spin labelling based perfusion-weighted MRI (ASL-PWI) facilitate the diagnosis. Germinomas are highly radiosensitive tumours, with survival rates >90% in the context of chemoradiotherapy. However, patients with resistant disease have limited therapeutic options and poor survival. The aim of this review is to highlight the genetic, epigenetic, and immunologic features, which could provide the basis for targeted therapy. Intracranial germinomas present genetic and epigenetic alterations (chromosomal aberrations, KIT, MAPK and PI3K pathways mutations, DNA hypomethylation, miRNA dysregulation) that may represent targets for therapy. Tyrosine kinase and mTOR inhibitors warrant further investigation in these cases. Immune markers, PD-1 (programmed cell death protein 1) and PD-L1 (programmed death-ligand 1), are expressed in germinomas, representing potential targets for immune checkpoint inhibitors. Resistant cases should benefit from a personalized management: genetic and immunological testing and enrolment in trials evaluating targeted therapies in intracranial germinomas.

Elucidation and control of low and high active populations of alkaline phosphatase molecules for quantitative digital bioassay

Alkaline phosphatase (ALP), a homo‐dimeric enzyme has been widely used in various bioassays as disease markers and enzyme probes. Recent advancements of digital bioassay revolutionized ALP‐based diagnostic assays as seen in rapid growth of digital ELISA and the emerging multiplex profiling of single‐molecule ALP isomers. However, the intrinsic heterogeneity found among ALP molecules hampers the ALP‐based quantitative digital bioassays. This study aims quantitative analysis of single‐molecule activities of ALP from Escherichia coli and reveals the static heterogeneity in catalytic activity of ALP with two distinct populations: half‐active and fully‐active portions. Digital assays with serial buffer exchange uncovered single‐molecule Michaelis–Menten kinetics of ALP; half‐active molecules have halved values of the catalytic turnover rate, k_cat, and the rate constant of productive binding, k_on, of the fully active molecules. These findings suggest that half‐active ALP molecules are heterogenic dimers composed of inactive and active monomer units, while fully active ALP molecules comprise two active units. Static heterogeneity was also observed for ALP with other origins: calf intestine or shrimp, showing how the findings can be generalized across species. Cell‐free expression of ALP with disulfide bond enhancer and spiked zinc ion resulted in homogenous population of ALP of full activity, implying that inactive monomer units of ALP are deficient in correct disulfide bond formation and zinc ion coordination. These findings provide basis for further study on molecular mechanism and biogenesis of ALP, and also offer the way to prepare homogenous and active populations of ALP for highly quantitative and sensitive bioassays with ALP.

Pineal Gland Tumors: A Review

Simple Summary

Pineal neoplasms are tumors with different and variable morphological, histological, and radiological characteristics and, consequently different diagnosis and management. Due to their rarity, pineal tumors may be misdiagnosed. Pineal tumors, are divided into germ cell tumors, pineal parenchymal tumors and tumors that derive from adjacent structures. In this review, we report the clinical relevance of the main pineal gland tumors, underlining the importance of studying the triggering causes of pineal region carcinogenesis, to realize appropriate diagnosis and, consequently, better clinical management.

Abstract

The pineal gland is a small, pinecone-shaped endocrine gland that participates in the biological rhythm regulation of vertebrates. The recognized major product of the pineal gland is melatonin—a multifunctional endogenous indoleamine. Accumulating evidence suggests that the pineal gland is important for preserving ideal health conditions in vertebrate. Tumors of the pineal region account for approximately 3–11% of pediatric brain neoplasms but fewer than 1% of brain neoplasms in adults. It is fundamental to expand advanced imaging techniques together with both clinical and laboratory knowledge, to help to differentiate among pineal neoplasms and thus facilitate accurate primary diagnoses and proper therapeutic interventions. In this review, we report the gross anatomy of the pineal gland and its functional significance and discuss the clinical relevance of pineal gland tumors, underlining the importance of identifying the leading causes of pineal region masses.

Mixed germ cell tumor infiltrating the pineal gland without elevated tumor markers: illustrative case

BACKGROUND

Tumors in the pineal region consist of various histological types, and correct diagnosis from biopsy specimens is sometimes difficult. The authors report the case of a patient with a mixed germ cell tumor infiltrating into the pineal gland despite showing no elevation of tumor markers.

OBSERVATIONS

An 18-year-old man complained of headache and nausea and showed disturbance of consciousness. Magnetic resonance imaging showed hydrocephalus associated with a cystic pineal tumor. The patient underwent tumor biopsy followed by endoscopic third ventriculostomy for hydrocephalus in a local hospital. A pineocytoma was diagnosed, and the patient was referred to the authors' hospital for treatment. Concentrations of placental alkaline phosphatase, alpha-fetoprotein (AFP), and beta-human chorionic gonadotropin in cerebrospinal fluid were not elevated. However, the authors' review of the tumor specimen revealed some immature cells infiltrating the pineal gland. These cells were positive for AFP, Sal-like protein 4, and octamer-binding transcription factor 3/4; and the diagnosis was changed to mixed germ cell tumor. Chemoradiotherapy was initiated, followed by surgical removal of the residual tumor.

LESSONS

Careful examination of all tumor specimens and immunohistochemical analyses are important for accurate diagnosis of pineal tumors.

Diagnostic Capability of Cerebrospinal Fluid-Placental Alkaline Phosphatase Value in Intracranial Germ Cell Tumor

OBJECTIVE

Most types of intracranial germ cell tumors (IGCTs) are sensitive to chemoradiation. However, biopsy specimens are usually small and thus cannot be used for obtaining an accurate pathological diagnosis. Recently, the cerebrospinal fluid (CSF) placental alkaline phosphatase (PLAP) value has been considered a new biomarker of IGCTs. The present study aimed to evaluate the discriminatory characteristics of the CSF-PLAP value upon diagnosis and at the time of recurrence in patients with IGCTs.

METHODS

Between 2015 and 2019, this study included 37 patients with tumors located in the intraventricular and/or periventricular region. The CSF-PLAP level was assessed before the patients received any treatment. The PLAP level was evaluated during and after first-line chemoradiotherapy in 7 patients with IGCTs. The CSF-PLAP values were compared according to histological diagnosis, and the correlation between these values and radiographical features was assessed. The CSF-PLAP values of 6 patients with IGCTs with suspected recurrence were evaluated based on neuroimaging findings.

RESULTS

The CSF-PLAP values were significantly higher in patients with IGCTs than in those with other types of brain tumor (n = 19 vs. 18; median: 359.0 vs. <8.0 pg/mL). The specificity and sensitivity were 88 and 95%, respectively, with a cutoff value of 8.0 pg/mL. In patients with IGCT, the CSF-PLAP value was higher in patients with germinoma than in those with nongerminomatous germ cell tumors (n = 12 vs. 7; median: 415.0 vs. 359.0 pg/mL). Regarding the time course, the CSF-PLAP value decreased to below the detection limit after the reception of first-line chemoradiotherapy in all 7 patients. A significant correlation was observed between the initial CSF-PLAP value and the tumor reduction volume after receiving first-line chemoradiotherapy (p < 0.0003, R2 = 0.6165, logY = 1.202logX - 1.727). Among the patients with suspected IGCT recurrence (n = 6), the CSF-PLAP value was high in patients with recurrence (n = 3; median: 259.0 pg/mL), and that in patients (n = 3) without recurrence was below the lower detection limit.

CONCLUSIONS

The CSF-PLAP level is a useful biomarker during the initial diagnosis of IGCTs and at the time of recurrence. It may be associated with the volume of germinomatous components of tumors.

Revisiting the pineal gland: a review of calcification, masses, precocious puberty, and melatonin functions

Introduction: The pineal gland, an endocrine organ of the posterior cranial fossa famously involved in sleep and wakefulness, has continually been a topic of scientific advancement and curiosity. Methods: We review present an up-to-date review including the anatomy, embryology, and physiology of the pineal gland and its ability to secrete hormones including melatonin, pathophysiology of pineal gland tumors, cysts, and calcifications, their clinical presentation including their association with parkinsonism and precocious puberty, and various treatment approaches. Results: Exploring the biochemistry of melatonin, various calcification morphologies, and pineal tumors may uncover a wider role and the exhaustive case study consolidation allows clinicians to carefully review the literature and aid their treatment approaches. Conclusion: It is imperative that clinicians and diagnosticians are able to distinguish manifestations of an overlooked gland.