title: Tumors of Schwann's cells and pigmented skin cells.
abstract: Both melanocytes and peripheral nerve sheath cells have an established origin from the neural crest. Benign and malignant neoplasms of these cells have distinctive ultrastructural features, but there is a group of tumors that has some characteristics of both cell types. The distinguishing feature of melanocytic neoplasms is the presence of cytoplasmic premelanosomes, which indicates cellular synthesis of melanin. Nerve-sheath neoplasms may show ultrastructural variation, but are generally found to have long cell processes associated with basal lamina-like material. Immunocytochemistry can be used to help distinguish tumors of melanocytic and Schwann's cells from unrelated neoplasms.
mesh_terms: D006801:Humans; D007124:Immunoenzyme Techniques; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000648:ultrastructure; D008854:Microscopy, Electron; D009442:Neurilemmoma / Q000648:ultrastructure; D009508:Nevus, Pigmented / Q000648:ultrastructure; D010524:Peripheral Nervous System Neoplasms / Q000648:ultrastructure; D012583:Schwann Cells / Q000473:pathology; D012878:Skin Neoplasms / Q000648:ultrastructure*