title: Signet-ring cell melanoma. A rare morphologic variant of malignant melanoma.
abstract: We recently received in consultation a lymph node involved by metastatic malignant melanoma with unusual and previously undescribed morphologic features. The neoplastic cells had a striking signet-ring appearance, similar to the signet-ring cells normally seen in mucin-producing adenocarcinoma and signet-ring cell lymphoma. Review of our consultation files of malignant melanomas revealed an additional case in which the neoplastic cells had a signet-ring cell appearance. Electron microscopic studies revealed that formation of signet-ring cells is caused by the presence of abundant vimentin filaments in the cytoplasm of neoplastic cells. Immunologic studies using a series of monoclonal and polyclonal antibodies, including S-100 protein, HMB-45, vimentin, cytokeratin, leukocyte common antigen, and Leu-M1, on both cases clearly established the diagnosis of this morphologically unusual variant of malignant melanoma for which we propose the term "signet-ring cell melanoma."
mesh_terms: D000328:Adult; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000951:Antigens, Neoplasm / Q000032:analysis; D005260:Female; D006649:Histocompatibility Antigens / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D017493:Leukocyte Common Antigens; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008545:Melanoma / Q000032:analysis / Q000473:pathology* / Q000601:surgery; D058950:Melanoma-Specific Antigens; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009418:S100 Proteins / Q000032:analysis; D014746:Vimentin / Q000032:analysis
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000951:Antigens, Neoplasm; D006649:Histocompatibility Antigens; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D009418:S100 Proteins; D014746:Vimentin; D007633:Keratins; D017493:Leukocyte Common Antigens