Sclerosing epithelioid fibrosarcoma

This is a rare form of fibrosarcoma, with 34 cases reported.

Clinical features

This tumour arises in deep locations such as deep fascia, periosteum and skeletal muscle.

Histopathology

There are zones of conventional fibrosarcoma as well as zones composed of cords and nests of small uniform polygonal cells with clear cytoplasm. There is abundant collagen with an osteoid-like appearance. Areas with a storiform pattern or myxoid stoma may be present. One case showed foci of high grade epithelioid appearance associated with evidence of nerve sheath differentiation2.

Immunohistochemistry

Ultrastructure

Where there is an anomalous phenotype with positivity for other than just vimentin, electron microscopic confirmation of fibroblastic differentiation is required3.

Differential diagnosis

• nodular fasciitis

• myositis ossificans

• fibromatosis

• hyalinising leiomyoma

• sclerosing lymphoma

• metastatic lobular carcinoma of breast

• ossifying fibromyxoid tumour

• monophasic synovial sarcoma

• clear cell sarcoma

• sclerosing rhabdomyosarcoma

• small cell osteosarcoma

• extra-skeletal myxoid chondrosarcoma

Prognosis

Some reports indicate that this is a relatively indolent tumour. However, one case showed early metastases2.

References

1Diagnostic Immunohistochemistry edited by Professor D. J. Dabbs, pages 93.

2Hanson, I. M., Pearson, J. M., Eyden, B. P., Slawik, S., Harris, M. Evidence of nerve sheath differentiation and high grade morphology in sclerosing epithelioid fibrosarcoma. J Clin Pathol 2001;54:721-723.

3Eyden, B. P., Manson, C., Banerjee, S. S., Roberts, I. S., Harris, M. Sclerosing epithelioid fibrosarcoma: a study of five cases emphasizing diagnostic criteria Histopathology 1998;33:354-60.

This page last revised 27.12.2001.