title: Malignant melanoma of the gallbladder.
abstract: A rare case of primary malignant melanoma of the gallbladder was studied with the electron microscope. Two interesting patterns were observed: numerous melanophages were present in the tumor tissue and wrapped compound melanosomes were found in nonneoplastic mucosal epithelium. The infiltration of melanophages was considered to be a reaction to degenerated tumor cells. Concerning the mechanism of melanosome transport into the epithelial cells, a cooperative action between epithelial and melanoma cells seemed to be the most important factor.
mesh_terms: D000368:Aged; D004848:Epithelium / Q000648:ultrastructure; D005706:Gallbladder Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology* / Q000648:ultrastructure; D008854:Microscopy, Electron