Large cell neuroendocrine carcinoma of the thymus

Aim: We highlight the occurrence of an unusual neuroendocrine tumour, a large cell neuroendocrine carcinoma, arising from the thymus. Case details: A 68-year-old man with a history of cigarette smoking had a large mediastinal tumour arising from the thymus removed, Two years later the tumour recurred; it was debulked surgically but the patient died 2 months later, Histological examination of both tumour specimens revealed a tumour with an endocrine pattern, composed of large pleomorphic cells with large nuclei and prominent nucleoli, The mitotic count ranged from 19 to 26 per 10 high-power fields and large tracks of coagulative tumour necrosis were present, The tumour cells were strongly positive for neuron-specific enolase (NSE), chromogranin, CAM5.2 and AE1/3, with cytoplasmic dot-like accentuation for the latter three markers, The tumour fulfilled the criteria for a diagnosis of large cell neuroendocrine carcinoma. Conclusions: Large cell neuroendocrine carcinoma should be distinguished from atypical carcinoid and small cell carcinoma, It is a distinctive neuroendocrine malignancy with a prognosis between that of atypical carcinoid and small cell carcinoma, and needs to be treated aggressively.