Neuroendocrine tumors of the thymus

Thymic carcinoid with multiple bone metastases: A case report

BACKGROUND

Thymic carcinoid (TC) is a rare entity among anterior mediastinal malignancies. TCs are neuroendocrine carcinomas that constitute approximately 2%–5% of all thymic epithelial tumors.

CASE SUMMARY

The study reported a rare TC with multiple bone metastases. A 77-year-old man presented with a 2-month history of lower back pain and weight loss of 5 kg. Magnetic resonance imaging scans revealed damage to the lumbar spine, sacrocaudal vertebrae and iliac crest, suggesting bone metastasis; computed tomography (CT) scan of the thorax showed a calcified anterior mediastinal mass; positron emission tomography-CT demonstrated multiple abnormal bone signals; and laboratory work-up showed no endocrine abnormalities. Fine-needle aspiration biopsy revealed predominantly single small, round to oval cells with scant cytoplasm and some loose clusters, suggesting endocrine manifestations. The pathological diagnosis was atypical carcinoid, which tend to originate from the thymus and was classified as intermediate-highly invasive. The patient underwent anlotinib-targeted therapy. Anlotinib (12 mg) was administered daily for 2 wk, after which the patient was allowed to rest for 21 d. Follow-up CT after one year demonstrated that the tumor had shrunk by approximately 29% after therapy. Treatment has a long stable disease benefit of more than 2.5 years.

CONCLUSION

These findings demonstrated that anlotinib is a promising treatment regimen for patients with TC and multiple bone metastases.

Analysis of 25 surgical cases of thymic neuroendocrine tumors and thymic carcinoma

BACKGROUND

The purpose of this study was to evaluate the clinicopathological characteristics of patients who underwent surgical resection for thymic neuroendocrine tumors (TNET) or thymic carcinoma.

METHODS

In this study, we retrospectively evaluated the clinicopathological characteristics of our surgical patients at Fukuoka University Hospital from January 1995 to December 2018.

RESULTS

There were nine cases of TNET and 16 cases of thymic carcinoma. Regarding the pathological type, the TNET group included three atypical carcinoid cases, two large cell neuroendocrine tumor cases, two small cell carcinoma cases, and two other cases. The thymic carcinoma group included 15 squamous carcinoma cases and one case of adenosquamous carcinoma. Based on the Masaoka-Koga staging system, six TNET cases and 11 thymic carcinoma cases were stage III or IV. The complete resection rate was 77% in the TNET group and 81% in the thymic carcinoma group. Additional chemotherapy and/or radiotherapy was performed in five cases of TNET and 11 cases of thymic carcinoma. The five-year survival rate and five-year disease-free survival rate were 87.5% and 75.0% in the TNET group and 58.9% and 57.1% in the thymic carcinoma group, respectively, with no significant difference between the two groups (P = 0.248 and P = 0.894, respectively). In the univariate analysis, complete resection was a statistically significant prognostic factor (P = 0.017).

CONCLUSION

In this study, no difference in prognosis was observed between TNET and thymic carcinomas. To understand the characteristics of these tumors, further case accumulation and multicenter clinical studies are needed. (243words).

The combination of etoposide and platinum for the treatment of thymic neuroendocrine neoplasms: A retrospective analysis

BACKGROUND

To provide real-world outcomes for the combination of etoposide and platinum as a first-line treatment for advanced thymic neuroendocrine neoplasms (TNENs).

METHODS

Retrospective analysis was performed on patients with advanced TNENs confirmed by pathology who received etoposide combined with platinum as a first-line chemotherapy in our institution between 2010 and 2022.

RESULTS

A total of 16 patients were included in this study. Twelve patients (75%) received etoposide combined with cisplatin, and four patients (25%) received etoposide combined with carboplatin. Efficacy was evaluated in all patients, with an objective response rate of 31.3%. One patient achieved a complete response, four achieved a partial response, and in eight patients the disease remained stable; the disease control rate was 81.3%. The median progression-free survival (PFS) was 7.2 months with a 95% confidence interval (CI) of 2.1-12.3 months. The median overall survival (OS) was 50.4 months with a 95% CI of 32.1-68.8 months. No significant difference in efficacy was observed between the treatment groups with regards to PFS (p = 0.095) and OS (p = 0.061). Treatment-related adverse events were observed in all 12 patients when evaluated for toxicity, manifesting as hematologic toxicity. Grade 3-4 bone marrow suppression occurred in six patients (50%). No treatment-related deaths were recorded.

CONCLUSION

This retrospective analysis, conducted in a real-life setting, suggests that the combination of etoposide and platinum has a promising anti-tumor activity in advanced TNENs, with a clinically significant overall response rate.

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

Epigenetics of Thymic Epithelial Tumors

Thymic epithelial tumors (TETs) arise from the epithelial cells of the thymus and consist in the 1% of all adult malignancies, despite the fact that they are the most common lesions of the anterior mediastinum. TETs can be divided mainly into thymomas, thymic carcinomas, and the rarest ad aggressive neuroendocrine forms. Despite the surgical resection is quite resolving, the diagnosis of TETs is complicated by the absence of symptoms and the clinical presentation aggravated by several paraneoplastic disorders, including myasthenia gravis. Thus, the heterogeneity of TETs prompts the search for molecular biomarkers that could be helpful for tumor characterization and clinical outcomes prediction. With these aims, several researchers investigated the epigenetic profiles of TETs. In this manuscript, we narratively review the works investigating the deregulation of epigenetic mechanisms in TETs, highlighting the need for further studies combining genetic, epigenetic, and expression data to better characterize the different molecular subtypes and identify, for each of them, the most relevant epigenetic biomarkers of clinical utility.

Continuing challenges of primary neuroendocrine tumours of the thymus: A concisereview

Primary neuroendocrine tumours of the thymus (NETTs) are exceedingly rare tumours, usually presenting around mid-life, which have a propensity towards males and smokers. They are seen more often in those with MEN-1, but multiple different genetic mutations have been found to be involved in the tumorigenesis of NETTs. Histologically, NETTs are classified according to number of mitoses, the presence of necrosis, and the presence or absence of small cell features. NETTs display a wide spectrum of behavior, and they can be incidentally found on chest imaging, on screening in MEN-1, or present with symptoms of local compression. Advanced disease and paraneoplastic syndromes are common. CT-, PET/CT-, MRI-scans, and somatostatin receptor scintigraphy are the imaging modalities of choice both for the initial assessment as well as for monitoring after treatment. For patients with localized disease, complete surgical resection with lymphadenectomy provides the best chance of long-term, disease-free survival, and can be achieved through either an open or thoracoscopic approach. While chemotherapy-regimens based on platinum, taxane, and temozolomide are used most often, the optimum chemotherapy regimen in the adjuvant and palliative settings remains unclear, as does the role of radiotherapy. Ongoing research on the most effective use of somatostatin analogues, peptide receptor radionuclide therapy (PPRT), kinase inhibitors and immunotherapy in patients with other types of advanced neuroendocrine tumours may lead to further treatment options for NETTs in the future.

Surgical treatment of intermediate to high grade thymic neuroendocrine neoplasms: case series of five patients and literature review

Background

Thymic neuroendocrine neoplasms (Th-NENs) are extremely rare. Th-NENs are divided into four pathological subtypes: typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell carcinoma (SCC). The latter three subtypes are highly aggressive with poor prognosis. There are limited reports on the optimal surgical strategies for Th-NENs. This study aims to report a case series of Th-NENs after surgical treatment and review the literatures.

Methods

We report a case series of five patients diagnosed with Th-NENs and summarize their clinical characteristics. Literatures related to surgical treatment of Th-NENs were reviewed.

Results

There were three males and two females, and mean age was 53.6 years. No myasthenia gravis or neuroendocrine symptoms were found. Three patients were diagnosed with AC and the other two were diagnosed with LCNEC. Two patients were stage II-b, one patient was stage III-a, and two patients were stage IV-b. One patient received preoperative chemotherapy, one patient received preoperative chemoradiotherapy, and three patients underwent surgery directly. Two patients underwent extended thymectomy via video-assisted thoracoscopic surgery (VATS), two patients underwent extended thymectomy via median sternotomy, and one patient underwent resection of anterior mediastinal tumor, sternal metastases, superior vena cava and partial right atrium via median sternotomy and cardiopulmonary bypass. R0 resection was achieved in 80% (4/5) of patients. There was no postoperative 90-day complication and death. One patient had no recurrence. One patient had lymph node metastases and was still alive after somatostatin analogue therapy. One patient had no recurrence of Th-NENs but died of other tumors. Two patients had distant metastases. Median overall survival (mOS) was 49 (range, 4-134) months. A total of 22 original studies related to surgical treatment of Th-NENs were retrieved.

Conclusions

Th-NENs is a very rare and extremely aggressive malignancy. Early diagnosis and surgical resection are the most important methods to improve prognosis. Radical resection and lymph node dissection are recommended for accurate staging and better prognosis. Currently, there are few clinical data on Th-NENs and several important surgical issues remain unresolved. In the future, multi-center, large-sample database and clinical studies are urgently needed to explore better treatment modality.

Thymic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1

OBJECTIVE

MEN1 is associated with an increased risk of developing tumors in different endocrine organs. Neuroendocrine tumors of the thymus (TNETs) are very rare but often have an aggressive nature. We evaluated patients with MEN1 and TNET in three university hospitals in Finland.

DESIGN/METHODS

We evaluated patient records of 183 MEN1-patients from three university hospitals between the years 1985-2019 with TNETs. Thymus tumor specimens were classified according to the new WHO 2021 classification of TNET. We collected data on treatments and outcomes of these patients.

RESULTS

There were six patients (3.3%) with MEN1 and TNET. Five of them had the same common gene mutation occurring in Finland. They originated from common ancestors encompassing two pairs of brothers from sequential generations. The mean age at presentation of TNET was 44.7 ± 11.9 years. TNET was classified as atypical carcinoid (AC) in five out of six patients. One patient had a largely necrotic main tumor with very few mitoses and another nodule with 25 mitoses per 2 mm², qualifying for the 2021 WHO diagnosis of large cell neuroendocrine carcinoma (LCNEC). In our patients, the 5-year survival of the TNET patients was 62.5% and 10-year survival 31.3%.

CONCLUSION

In this study, TNETs were observed in one large MEN1 founder pedigree, where an anticipation-like earlier disease onset was observed in the most recent generation. TNET in MEN1 patients is an aggressive disease. The prognosis can be better by systematic screening. We also show that LCNEC can be associated with TNET in MEN1 patients.

Real-world clinicopathological features and outcome of thymic neuroendocrine tumors: a retrospective single-institution analysis

Background

Thymic neuroendocrine tumors comprise a heterogeneous group of rare diseases. This study aimed to investigate the real-world clinicopathological features and treatment outcomes of thymic neuroendocrine tumors.

Results

A total of 104 patients diagnosed with thymic neuroendocrine tumors in a single institution from 1983 to 2021 were eligible. Fourteen (13.46%) and 28 (26.92%) patients diagnosed with thymic neuroendocrine tumors suffered from multiple endocrine neoplasia and ectopic adrenocorticotropic hormone syndrome, respectively. Ninety-seven (93.27%) patients underwent surgical resection, including 79 (81.44%) with radical resection. Except for 5 patients lost during follow-up, the 1-, 3- and 5-year overall survival rates were 91.8%, 70.2% and 54.6%, respectively. The median overall survival was 61.57 months. Multivariate analysis revealed that years at diagnosis (HR 0.559, 95% CI 0.364–0.857, p = 0.008), radical resection (HR 2.860, 95% CI 1.392–5.878, p = 0.004), pathological grade (HR 1.963, 95% CI 1.058–3.644, p = 0.033) and Masaoka–Koga stage (HR 2.250, 95% CI 1.548–3.272, p = 0.000) exerted significant differences in overall survival among 99 patients. In the surgery group, multivariate Cox regression analysis exhibited significant overall survival differences in years at diagnosis (HR 0.563, 95% CI 0.367–0.866, p = 0.009), neoadjuvant therapy (HR 0.248, 95% CI 0.071–0.872, p = 0.030), radical resection (HR 3.674, 95% CI 1.685–8.008, p = 0.001), pathological grade (HR 2.082, 95% CI 1.098–3.947, p = 0.025) and Masaoka–Koga stage (HR 2.445, 95% CI 1.607–3.719, p = 0.000).

Conclusions

Radical resection and Masaoka–Koga stage were independent prognostic factors for the survival of patients with thymic neuroendocrine tumors. Systemic therapy and integrated management of patients with advanced-stage disease require high-level clinical evidence.

[Mediastinal lesions : The most common pathologies in chest X-rays and their correlations in computed tomography]

BACKGROUND

Many pathologies of the mediastinum can be diagnosed using standard radiographs. Correlation of radiographic findings with computed tomography (CT) is instructive for a better understanding and can help improve detection rates of mediastinal lesions.

OBJECTIVES

To identify the most common mediastinal lesions and to correlate their features in chest radiographs and CT.

METHODS

The International Thymic Malignancy Interest Group (ITMIG) classification in the anterior, middle, and posterior mediastinum is based on anatomic landmarks. Used as a tool to characterize mediastinal lesions this classification is applied in this article.

RESULTS

The most common lesions include mediastinal goiter, germ cell and thymic neoplasms in the anterior mediastinum, lymphadenopathy in the middle mediastinum, and neurogenic neoplasms in the posterior mediastinum. Other lesions of neoplastic or non-neoplastic origin can be distinguished in the three compartments and should be considered in the differential diagnosis.

CONCLUSIONS

Knowledge of the most common pathologies in the three mediastinal compartments can accelerate differential diagnosis. Understanding the normal mediastinal lines is key in anatomic localization and detection of many lesions in chest radiographs.

The Rarest of Rare Thymic Lesions: A 10-Year Surgical Pathology Experience

The thymus is a specialized primary lymphoid organ located in the midline pre-vascular mediastinum. The organ is the site of various pathological processes, neoplastic and not, whose rarity has not allowed in-depth studies on clinical or histological features of rarest and unusual variants. Herein, we report a 10-year Padova experience in the surgical pathology of the thymus, focusing on the pathological description of nonneoplastic lesions and rare epithelial and mesenchymal tumors recorded in our database, which comprises over 600 thymectomies. The extrapolated rare cases have been categorized into four groups that included 15 cysts, 18 carcinomas, 5 neuroendocrine tumors, and 2 soft tissue tumors. The cases are described from a clinical and pathological point of view and discussed in dedicated sections with a review of the most important literature. In this case, review series, we aim to update the epidemiology of these rare entities, improve diagnostic awareness, and finally, promote a collaborative network between referral centers.

Multiple endocrine neoplasia 1: a broad overview

This review article discusses the diagnoses and treatment of patients with multiple endocrine neoplasia type 1 (MEN 1). The most common tumors associated with MEN 1 are located in the pancreas, pituitary, and parathyroid glands. Less common tumors include neuroendocrine tumors of the lung and thymus, adrenal tumors, and cutaneous lesions. This article describes the diagnosis, clinical manifestations, treatment, and surveillance of tumors associated with patients who are diagnosed with MEN 1.

A rare initial presentation of a thymic neuroendocrine tumor as Cushing's syndrome

While evaluating the cause of Cushing's syndrome, biochemical confirmation should be sought first as imaging studies might misdirect the diagnosis toward the wrong problem. One of the rare secondary causes that should be kept in mind while evaluating Cushing's syndrome is the thymic neuroendocrine tumor.

Atypical Carcinoid Tumor of the Mediastinum Presenting as Cushing's Syndrome in an Otherwise Healthy Young Male

Primary neuroendocrine tumors (NETs) are rare types of malignancies that can have a variety of presentations due to the ubiquitous distribution of neuroendocrine cells within the body. While mediastinal masses are not uncommon, NETs arising from the anterior mediastinum are rare and often originate from the thymus gland. A subset of NETs, atypical carcinoids, are more commonly seen in the lungs or gastrointestinal organs and often present with endocrine syndromes, chiefly Cushing’s syndrome. The behavior of atypical carcinoid tumors within the mediastinum is often aggressive and clinical presentations vary widely. In this report, we describe a case of an atypical carcinoid tumor within the anterior mediastinum in an otherwise healthy young male with signs and symptoms of Cushing’s syndrome.

Potential Prognostic Value of Preoperative Leukocyte Count, Lactate Dehydrogenase and C-Reactive Protein in Thymic Epithelial Tumors

Thymic epithelial tumors are the most common mediastinal tumors. Surgery is the mainstay of treatment and complete resection provides the best survival rate. However, advanced tumors often require multimodality treatment and thus we analyzed the prognostic potential of routine circulating biomarkers that might help to risk-stratify patients beyond tumor stage and histology. Preoperative values for white blood cell count (WBC), C-reactive protein (CRP) and lactate dehydrogenase (LDH) were analyzed in 220 thymic epithelial tumor patients operated between 1999 and 2018. Increased CRP levels (>1 mg/dl) were significantly more often measured in thymic carcinoma and neuroendocrine tumors when compared to thymoma. LDH serum activity was higher in thymic neuroendocrine tumors when compared to thymoma or thymic carcinoma. The median disease specific survival was significantly longer in thymoma cases than in thymic carcinoma and neuroendocrine tumors. Increased preoperative LDH level (>240 U/L) associated with shorter survival in thymus carcinoma (HR 4.76, p = 0.0299). In summary, higher CRP associated with carcinoma and neuroendocrine tumors, while LDH increased primarily in neuroendocrine tumors suggesting that biomarker analysis should be performed in a histology specific manner. Importantly, preoperative serum LDH might be a prognosticator in thymic carcinoma and may help to risk stratify surgically treated patients in multimodal treatment regimens.

Cardiac metastasis of neuroendocrine tumor of the thymus diagnosed by cardiac magnetic resonance T1 mapping: a case report

Carcinoid heart disease is a late complication of carcinoid syndrome, and imaging can help in the diagnosis of diffuse cardiac metastasis. We herein report a case of diffuse cardiac metastasis of a neuroendocrine tumor of the thymus diagnosed using different imaging modalities. Cardiac magnetic resonance imaging played an important role in the diagnosis. The patient underwent conservative medical treatment and remained able to perform his usual activities of daily living.

Radiotherapy for thymic epithelial tumours: a review

Thymic epithelial tumours (TETs) represent a rare disease, yet they are the most common tumours of the anterior mediastinum. Due to the rare occurrence of TETs, evidence on optimal treatment is limited. Surgery is the treatment of choice in the management of TETs, while the role of postoperative radiotherapy (PORT) remains unresolved. PORT remains debated for thymomas, especially in completely resected stage II tumours, for which PORT may be more likely to benefit in the presence of aggressive histology (WHO subtype B2, B3) or extensive transcapsular invasion (Masaoka-Koga stage IIB). For stage III thymoma, evidence suggests an overall survival (OS) benefit for PORT after complete resection. For incompletely resected thymomas stage II or higher PORT is recommended. Thymic carcinomas at any stage with positive resection margins should be offered PORT. Radiotherapy plays an important role in the management of unresectable locally advanced TETs. Induction therapy (chemotherapy or chemoradiation) followed by surgery may be useful for locally advanced thymic malignancies initially considered as unresectable. Chemotherapy only is offered in patients with unresectable, metastatic tumours in palliative intent, checkpoint inhibitors may be promising for refractory diseases. Due to the lack of high-level evidence and the importance of a multidisciplinary approach, TETs should be discussed within a multidisciplinary team and the final recommendation should reflect individual patient preferences.

ACTH-dependent Hypercortisolemia in a Patient with a Pituitary Microadenoma and an Atypical Carcinoid Tumour of the Thymus

Cushing's syndrome (CS) is a set of clinical symptoms which occur as a result of hypercortisolemia. Endogenous ACTH-dependent CS related to an ectopic ACTH-secreting tumour constitutes 12%-17% of CS cases and is one of the most common causes of paraneoplastic syndromes. This study presents a case of a 31 year-old man with diabetes, hypertension, rosacea, purple stretch marks and hypokalemia. Findings of diagnostic procedures include high concentrations of cortisol and ACTH, pituitary microadenoma and a tumour in the anterior mediastinum. Dynamic hormone tests determined the source of excess hormone secretion and ectopic ACTH-dependent CS was diagnosed. Due to increasing symptoms of superior vena cava syndrome, an emergency resection of almost the whole tumour was performed, with only a small part of the upper pole left because of the proximity of large vessels and a risk of damaging them. On the basis of histopathological tests, an atypical carcinoid tumour of the thymus was identified. Immediately after the surgical procedure, there was a significant reduction of clinical and laboratory traits of hypercortisolemia, yet, during the 46 weeks of postoperative observation, despite chemotherapy, the progression of residual masses of the tumour occurred with metastases and increased hormone indices. The presented case shows and discusses the differentiation of ACTH-dependent hypercortisolemia and its causes, difficulties in surgical therapy and chemotherapy, as well as prognosis for atypical carcinoid of the thymus, which is a rare disease.

Evaluation of the prognostic value of surgery and postoperative radiotherapy for patients with thymic neuroendocrine tumors: A propensity-matched study based on the SEER database

Background

The prognostic value of surgery and postoperative radiotherapy (PORT) for primary thymic neuroendocrine tumors (TNETs) was estimated using the SEER database.

Methods

This retrospective study used SEER data of TNET patients between 1998 and 2015. Propensity score matching (PSM) was performed according to whether surgery was performed. The prognostic effects on overall survival (OS) and cancer‐specific survival (CSS) were evaluated using multivariate Cox regression.

Results

A total of 3947 patients were included: 293 (7.4%) TNET, 2788 (70.6%) thymoma, and 866 (21.9%) thymic carcinoma. Compared to other subtypes, TNET patients were younger, included a larger proportion of men, had a well or moderately differentiated histological grade, higher disease stage at diagnosis, and were more likely to have regional lymph node metastasis. The median OS and CSS for TNET were 82.9 (95% confidence interval 74.3–91.4) and 101.9 (95% confidence interval 91.9–111.8) months, respectively, significantly shorter than for thymomas. In the matched cohort of TNET patients, multivariate analysis of OS and CSS revealed a significantly poorer prognosis in the non‐surgery group (P < 0.001). Compared to total/radical resection, TNET patients who underwent debulking resection had significantly inferior outcomes (P < 0.05). Postoperative radiotherapy favorably impacted OS and CSS in Masaoka–Koga stage III–IV TNET patients; this OS impact was also observed in stage IIB patients.

Conclusion

TNETs are extremely rare with relatively dismal outcomes. This analysis revealed the role of complete surgical resection and the favorable effect of postoperative radiotherapy in specific TNET subgroups.