Fibrosarcoma C49.9

Very rare, malignant connective tissue tumour, usually originating from tendons or fasciae (rarely primarily originating from the cutis) and rapidly metastasising with proliferation of spindle-shaped cells.

Remark: The diagnosis "fibrosarcoma" was made more frequently in earlier years, but is now more in the background due to the more differentiated possibilities of subtle immunohistological tissue characterization. Today, <1% of adult fibroblastically differentiated sarcomas are diagnosed with fibrosarcoma. In this respect, the summary presented here refers to older scientific data.

Primary cutaneous fibrosarcomas develop preferentially in long existing atrophic scars, e.g. in lupus erythematosus, burns, radiodermatitis chronica.

Possible at any age. Age peak around the age of 40.

Especially extremities (thighs); possible everywhere.

Fast-growing, subcutaneous, usually painless, very coarse, with the underlay baked knots on the extremities; rather plate-like infiltrates on the trunk. Early ulceration on exit from the cutis, bluish-brownish surface. Early haematogenic metastasis mainly in the lungs.

Densely packed, atypical, fish-like, spindle-shaped cells arranged in fascicular patterns, numerous mitoses. Negative for CD34. Highly differentiated tumors are less cell-deficient and richer in collagen fibers than low differentiated ones. The more pronounced the anaplasia of the cells, the more they lose their spindle shape. Occasionally secretion of a myxoid substance (fibromyxosarcoma).

Dermatofibrosarcoma protuberans; malignant fibrous histiocytoma; fasciitis nodularis pseudosarcomatosa; desmoid tumor; leiomyosarcoma; undifferentiated spinocellular carcinoma.

The fibrosarcoma responds little to radiotherapy.

Chemotherapy: Effectiveness of adjuvant cytostatic therapy ( vincristine, doxorubicin, cyclophosphamide) has not been proven to date. Treatment in collaboration with oncologists.

Early radical excision with a safety margin of at least 2 cm leads to fewer local recurrences. However, the metastasis potential and thus survival are determined by the degree of differentiation of the tumor cells.

5-year survival rate 50%, prognosis of childhood fibrosarcoma is significantly better than that of adults.

1. Diaz-Cascajo C et al (2003) Fibroblastic/myofibroblastic sarcoma of the skin: a report of five cases. J Cutan Pathol 30: 128-134
2. Hill H (2006) Fibrohistiocytic skin tumors. J Dtsch Dermatol Ges 4: 544-555
3. Jurcic V et al (2002) Myxoinflammatory fibroblastic sarcoma: a tumor not restricted to acral sites. Ann Diagn Pathol 6: 272-280
4. Scott SM et al (1989) Soft Tissue Fibrosarcoma. Cancer 64: 925-931
5. Sheng WQ et al (2001) Congenital-infantile fibrosarcoma. A clinicopathologic study of 10 cases and molecular detection of the ETV6-NTRK3 fusion transcripts using paraffin-embedded tissues. At J Clin Pathol 115: 348-355