title: Pseudosarcomatous carcinoma of the anal canal.
abstract: A polypoid pseudosarcoma of the anal canal in a 45-year-old woman was surgically treated. Morphologic characteristics of the tumor were essentially identical with those in hitherto-described pseudosarcomas of the esophagus, larynx, fauces, or oral cavity. Histologic features of the tumor support the presumption of epithelial origin of the sarcoma-like element on the basis of the presence of a clearly epithelial element in the sarcoma-like areas, justifying the term "pseudosarcomatous carcinoma," instead of "pseudosarcoma." This is the first report of this tumor type detected in the anal canal.
mesh_terms: D002277:Carcinoma / Q000473:pathology* / Q000648:ultrastructure; D003937:Diagnosis, Differential; D005260:Female; D005350:Fibroma / Q000473:pathology / Q000648:ultrastructure; D006801:Humans; D008854:Microscopy, Electron; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D012007:Rectum / Q000473:pathology / Q000648:ultrastructure