[Ossifying fibromyxoid tumor of soft parts: a clinicopathological analysis of eight cases].
OBJECTIVE
To study the morphological characteristics and immunophenotype of ossifying fibromyxoid tumor of soft parts (OFT) with a discussion of its histogenesis.


METHODS
The clinical, pathological and immunohistochemical features of 8 cases of OFT were evaluated.


RESULTS
All 8 cases were middle to old aged patients, ranged from 43 -- 78 years (mean 63 years). Clinically, the majority presented as slowly growing painless masses that located in subcutis of the proximal extremities. Histologically, the tumor was characterized by the following three unique features which have diagnostic value. (1) The tumor was well circumscribed and encapsulated with an incomplete bony shell composed of metaplastic bone within the capsule in most cases; (2) The tumor parenchyma consisted of lobules of variable size and cellularity. The tumor cells within each lobule were rounded to short spindled with pale-staining or eosinophilic cytoplasm; (3) The tumor cells arranged in nests, cords, or laciform pattern, and were embedded in a characteristic fibromyxoid to collagenized stroma. Immunohistochemically, all 7 cases tested were positive for vimentin and NSE, while 6 cases expressed S-100 protein and 2 cases expressed desmin. Follow-up information showed recurrences in two patients 2 and 15 years after local excision.


CONCLUSIONS
OFT is a distinctive soft tissue tumor of potentially low-grade malignancy which occurred predominantly in middle to old aged patients. The characteristic bony shell, the unique cytological appearance and arrangement of the cells are pathognomonic features of OFT. Our immunohistochemical result supported a Schwann-cell origin.
Wang
J
J
Department of Pathology, Cancer Hospital, Medical College of Fudan University, Shanghai 200032, China.
Lu
H
H
Zhu
X
X
Zhang
R
R
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D018214:Fibroma, Ossifying / Q000737:chemistry / Q000473:pathology*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009442:Neurilemmoma / Q000473:pathology; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D009418:S100 Proteins / Q000032:analysis; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000473:pathology*; D014746:Vimentin / Q000032:analysis
D009418:S100 Proteins; D014746:Vimentin; D010751:Phosphopyruvate Hydratase