title: Selected case from the Arkadi M. Rywlin International Pathology Slide Seminar: desmoplastic fibroblastoma (collagenous fibroma).
abstract: Desmoplastic fibroblastoma (collagenous fibroma) is a rare and recently described benign soft tissue tumor. It is more common in men, median age is 50 years, the history is usually long, and the usual size is around 3 cm. Most lesions are subcutaneous but approximately 25% involve skeletal muscle. Histologically, they are sparsely cellular with stellate and spindle-shaped fibroblasts-myofibroblasts that are separated by a collagenous or myxocollagenous matrix. Mitoses are minimal or absent. Tumor cells are focally positive for muscle-specific and alpha smooth muscle actins, and rarely, for keratins. The S-100 is usually negative but a very few cases have been positive. It can be confused with one of the fibromatoses, myxomas of various kinds and neural tumors. It neither recurs nor metastasizes.
authors.affiliation: Department of Anatomical Pathology, Flinders Medical Centre, Bedford Park, South Australia. phil.allen@fmc.sa.gov.au
authors.forename: P W
authors.initials: PW
authors.lastname: Allen
mesh_terms: D018220:Fibroma, Desmoplastic / Q000737:chemistry / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008545:Melanoma / Q000150:complications / Q000473:pathology / Q000601:surgery; D009378:Neoplasms, Multiple Primary; D009418:S100 Proteins / Q000032:analysis; D012878:Skin Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000150:complications / Q000175:diagnosis* / Q000601:surgery
chemical_list: D009418:S100 Proteins