Thick collagen bands are interspersed among the round/ovoid cells with clear cytoplasm/
The epithelioid cells are arranged in cords or nests against the dense collagenous background. The cells are rather monomorphous, with clear or vacuolated cytoplasm.
Sclerosing epithelioid fibrosarcoma is a variant of fibrosarcoma. Parenthetically, fibrosarcoma has several distinct variants which are: sclerosing epithelioid fibrosarcoma, fibrosarcoma arising from DFSP, low grade fibromyxoid sarcoma and myxofibrosarcoma.
SEF was first identified in 1995 by Meis-Kindblom et al. The lesion is characterized by epithelioid cells arranged in strands, nests and sheets against a fibrous and hyalinzed stroma. Often times, there are features resembling low-grade fibromyxoid sarcoma (myxoid areas adjacent to paucicellular fibrous areas) and foci of conventional fibrosarcoma (Antonescu).
Because of the epithelioid morphology of the cells, malignant lymphoma or metastatic carcinoma may arise on the differential. The only consistent immunomarker for SEF is vimentin.
Grossly, the tumor is generally large (9cm+) with a white-tan lobulated hard cut surface.
In a study of 16 cases conducted by Antonescu et al, the patients ranged from 14-55 years of age (mean age 40), 6 were male and 10 were female. The favored sites were limb or limb girdle (7 cases) and head and neck (5 cases). The remainder of cases were located in the back or chest wall (3 cases) and base of penis (1 case). SEF usually presents as a painless slow-growing mass.
This is a tumor that behaves in a malignant fashion. In the 16 cases reviewed by Antonescu (2001), 14 cases were available for followup. Of those, 7 patients (50%) had persistent disease or local recurrence. Distant metastasis was seen in 12 (86%) of patients and 8 patients (57%) died of their disease.
→Sclerosing epithelioid fibrosarcoma is considered a distinct variant of fibrosarcoma.
→SEF is a fairly aggresive variant of fibrosarcoma.
→Unlike low-grade fibromxyosarcoma and fibrosarcoma arising from DFSP (other variants of fibrosarcoma), SEF does not exhibit a particular chromosomal translocation.
Antonescu CR, et al. Sclerosing epithelioid fibrosarcoma: a study of 16 cases and confirmation of a clinicopathologically distinct tumor. Am J Surg Pathol. 2001 Jun;25(6):699-709.
Meis-Kindblom JM, Kindblom LG, Enzinger FM. Sclerosing epithelioid fibrosarcoma. A variant of fibrosarcoma simulating carcinoma. Am J Surg Pathol. 1995 Sep;19(9):979-93.