[A case of S 100 protein-positive large cell carcinoma--its pathological study]

We have experienced a case of S 100 protein positive large cell carcinoma of the lung which metastasized to the jejunum. The present case had a somewhat morphological resemblance to a Ki-1 lymphoma and/or an interdigitating cell sarcoma, and its differential diagnosis was problematic. This type of case, to our knowledge, is rare in the literature. The morphologic, immunohistologic, and electron microscopical findings of the neoplastic cells are described in this study.