A Case of Metastatic Small Cell Neuroendocrine Carcinoma of the Lung Mimicking a Merkel Cell Carcinoma / 대한피부과학회지

ABSTRACT

Metastatic small cell neuroendocrine carcinomas(MSCNC) from distant sites, such as the lung, are high grade tumors with poor prognosis. Histopathologically, it is difficult to distinguish between MSCNC and Merkel cell carcinoma solely on the basis of histologic morphology, electron microscopy, and immunohistochemistry. In recent years, differential expression of cytokeratin(CK) 20 and thyroid transcription factor(TTF)-1 has been proposed as useful distinguishing features. It must be emphasized that clinical correlation(e.g. symptomatology, chest X-ray) and a combination of CK 20 and TTF-1 markers, are essential to differentiate these two disease entities. We herein present a case of MSCNC of the lung that might be misdiagnosed as Merkel cell carcinoma.