title: Immunohistochemical and ultrastructural investigation on cutaneous neuroendocrine carcinoma: report of a case and review of the literature.
abstract: We report a tumor in an 80-year-old man that was difficult to distinguish from other tumors, i.e., small cell carcinoma of the lung, PNET/Ewing tumor, malignant lymphoma, or malignant melanoma (amelanotic), and which was finally identified as cutaneous neuroendocrine carcinoma using immunohistochemical and ultrastructural methods. Autopsy did not show any tumors in the lungs, excluding the possibility of small cell carcinoma of the lung. Immunohistochemistry tests gave negative results for LCA, UCHL-1, CD3, and CD20, thereby excluding malignant lymphoma, and the negative results for S-100 protein and HMB-45 ruled out malignant melanoma. The possibility of PNET/Ewing sarcoma was also excluded because of negativity for CD99. In addition, the ultramicrostructure showed intercellular junctional complexes and neuroendocrine granules, indicating that the tumor had characteristics of both epithelial and neuroendocrine tissues. We therefore diagnosed the primary carcinoma of the skin as cutaneous neuroendocrine carcinoma.
authors.affiliation: Department of Pathology, Tokyo Medical University, 6-1-1 Shinjuku, Tokyo 160-8402, Japan. hhishii@tokyo-med.ac.jp
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Joshita
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Matsuyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Uchida
authors.forename: Akio
authors.initials: A
authors.lastname: Ishikawa
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Ebihara
mesh_terms: D000369:Aged, 80 and over; D018278:Carcinoma, Neuroendocrine / Q000175:diagnosis / Q000648:ultrastructure*; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D012878:Skin Neoplasms / Q000175:diagnosis / Q000648:ultrastructure*