title: Hyalinizing spindle cell tumor with giant rosettes: a distinctive tumor closely resembling low-grade fibromyxoid sarcoma.
abstract: We report the findings of 19 cases of a previously undescribed spindle cell tumor of soft tissues that resembles a low-grade fibromyxoid sarcoma but contains distinctive rosettelike structures. The tumors occurred principally as a painless, slowly growing, deeply situated mass of the proximal extremities in young to middle-aged adults (age range 14-65 years; mean 38). Although grossly circumscribed, the tumors had infiltrative borders microscopically and were composed of bland spindled cells situated in a hyalinized to myxoid stroma. The most characteristic feature of the tumor was scattered large rosettelike structures that often merged with serpinginous areas of dense hyalinization. The rosettes consisted of a central collagen core surrounded by a rim of rounded cells morphologically and immunophenotypically different from the cells of the spindled stroma. These cells expressed a number of antigens, including S-100 protein, neuron-specific enolase, and leu 22, in contrast to the stroma, which usually lacked these antigens. Of the 12 patients with available follow-up information, one patient treated with simple excision clinically developed local recurrence of the tumor 20 months after initial biopsy. No other recurrences were reported during the limited follow-up period, and no patient developed metastatic disease. However, the favorable prognosis of the patients in our series to date may relate to the limited follow-up period (approximately 3 years), as well as initial treatment by wide excision in nearly half of the patients. We regard the hyalinizing spindle cell tumor with giant rosettes as a distinctive type of low-grade fibroblastic tumor that with time may prove to behave similar to a low-grade fibromyxoid sarcoma and, hence, to represent an unusual variant thereof.
authors.affiliation: Department of Pathology, University of Michigan Hospitals, Ann Arbor 48109-0054, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Lane
authors.forename: R J
authors.initials: RJ
authors.lastname: Shannon
authors.forename: S W
authors.initials: SW
authors.lastname: Weiss
mesh_terms: D000199:Actins / Q000032:analysis; D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D003893:Desmin / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D005350:Fibroma / Q000473:pathology / Q000601:surgery; D005354:Fibrosarcoma / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007633:Keratins / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000473:pathology / Q000601:surgery; D010524:Peripheral Nervous System Neoplasms / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D009418:S100 Proteins / Q000032:analysis; D012983:Soft Tissue Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D014746:Vimentin / Q000032:analysis
chemical_list: D000199:Actins; D015703:Antigens, CD; D003893:Desmin; D009418:S100 Proteins; D014746:Vimentin; D007633:Keratins