Abstract

Pulmonary tumors exhibiting neuroendocrine differentiation are classified as typical carcinoid, atypical carcinoid, and small cell lung carcinoma(SCLC). Travis et al. proposed a fourth category of large cell neuroendocrine carcinoma, which is characterized by light microscopic neuroendocrine appearance, cells of large size, polygonal shape, low nuclear cytoplasmic ratio, coarse nuclear chromatin, with prominent nucleoli high mitotic rate and frequent necrosis; and neuroendocrine features by immunohistochemistry or electron microscopy. High grade neuroendocrine carcinoma (LCAC-NE) revealed aggressive clinical course. We report two cases of neuroendocrine tumors of the lung characterized by a trabecular pattern of large pleomorphic cells with frequent mitoses and wide necrosis. The frequent metastatic sites of atypical carcinoid were liver, bone and brain. One of our case is presented, at first, as an ovarian mass, which shows multifocal rosettes and revealed metastasis from lung. Both cases expressed neuroendocrine differentiation by light microscopy and immunohistochemistry. However clinical neuroendocrine symptom were not present.

• Keywords: Neuroendocrine tumor;Large cell;Lung;Ovary;