Clinicopathological Analysis of 21 Thymic Neuroendocrine Tumors

Abstract

BackgroundThymic neuroendocrine carcinomas (NECs) are uncommon, for which there is no established information available because of a limited number of epidemiological study in Asia.MethodsWe reviewed 21 cases of surgically resected thymic NECs, and evaluated their pathological and clinical features.ResultsIt showed male predominance (male/female ratio, 15/6) with wide age range from 20 to 72 years (mean age, 49 years). All 21 cases were divided into two types according to the World Health Organization criteria: atypical carcinoid (n=18) and large cell NEC (n=3). Three cases of atypical carcinoid (AC) were associated with ectopic Cushing's syndrome. All the patients (3/3) with large cell NEC (3/3) and 16.7% (3/18) of those with AC died of tumor progression. Common sites of metastasis included lung, lymph node, brain, lumbar spine, mediastinum, bone, and liver.ConclusionsIn conclusion, thymic neuroendocrine tumors carry a poor prognosis. Regarding the tumor classification, our results showed that a vast majority of carcinoids in the thymus correspond to ACs. In addition, our results also indicate that typical carcinoid is a very rare entity. Some cases of AC exhibited a large size, solid pattern and they showed aggressive clinical behavior, which highlights the spectrum of histologic appearances of thymic NECs.

Thymic Neuroendocrine Neoplasms: Biological Behaviour and Therapy

“…Some studies have suggested that the current grading system does not highly correlate with survival, while adding a Ki-67 assessment did show statistical significance in terms of survival [8,9] . In the series reported by Ahn et al [10] , 3 of the patients showed mitotic counts of more than 10 per 10 high-power fields but did not show a lack of differentiation: the clinical behaviour of the tumours in these patients supported a diagnosis of AC ( Fig. 1 ).…”

Neuroendocrine tumors of the thymus and mediastinum

“…LCNEC account for about 15-25% of neuroendocrine thymic tumors (51,52) and affect twice as many men as women. The estimated incidence is 1 per 20 million inhabitants (1).…”

“…Approximately half of the patients present with chest pain, dyspnea or upper inflow congestion. The other half of the patients are asymptomatic (51,52). Paraneoplastic phenomena through hormone production (for example Cushing's syndrome) are rare (53).…”

“…At the time of diagnosis, about 75% of tumors show an infiltration of adjacent organs or distant metastases e.g., to spine and liver (51,59).…”

Neuroendokrine Neoplasien des Mediastinums

“…Der thyroidale Transkriptionsfaktor-1 (TTF1) ist typischerweise negativ [23]. In einzelnen Tumorzellen sind einige Hormone wie das adrenokortikotrope Hormon (ACTH), Calcitonin, Somatostatin oder humanes Choriongonadotropin (HCG) typischerweise immunhistochemisch positiv, wobei sich keine Korrelation zur klinischen Präsentation ergibt [1].…”