title: Pseudosarcomatous changes in inflammatory pseudopolyps of the colon.
abstract: The occurrence of pseudomalignant changes in biopsy specimens from two patients with ulcerative colitis and pseudopolyposis is described. One lesion was characterized by the proliferation of large ganglion cell-like cells, similar to those observed in proliferative fasciitis. Ultrastructural and immunohistochemical findings supported a fibroblastic origin. Biopsy specimens of an inflammatory pseudopolyp from the second patient showed proliferation of oval to spindle cells that were initially interpreted as a possible neoplasm. The site of origin and reactive nature of this lesion became apparent on a subsequent polypectomy specimen. Attention is called to the occurrence of pseudosarcomatous changes in inflammatory pseudopolyps of the gastrointestinal tract that may lead to an erroneous diagnosis of malignancy.
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D003093:Colitis, Ulcerative / Q000473:pathology; D003110:Colonic Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D003111:Colonic Polyps / Q000473:pathology* / Q000648:ultrastructure; D005350:Fibroma / Q000473:pathology* / Q000648:ultrastructure; D006651:Histocytochemistry; D006801:Humans; D008297:Male; D008854:Microscopy, Electron