Soft Tissue, Gardner-type Fibroma

Soft tissue fibromas, when presenting in childhood or adolescence, are both uncommon and may indicate an association with Gardner syndrome: a mutation of the APC gene requiring close monitoring for precursors of colon cancer. There is also a risk for future occurrences of desmoid fibromatoses. In this case, a clear familial history or germline status was not provided; therefore, further evaluation may be suggested. (In up to 10% of cases, a clear association with familial adenomatous polyposis/Gardner syndrome is not found.)

This fibrous lesion occurs in the scalp—one of the more common sites (along with paraspinal) for Gardner fibroma. Sections show diffuse hypocellular sheets of haphazardly arranged, coarse collagen fibres with scattered bland spindle cells, and sparse mast cells. Clear cracks between collagen fibers are seen. Some entrapped fat and nerves are identified. Immunohistochemistry revealed the neoplastic cells to express CD34. Desmin, SMA, S100, Cyclin-D1, and beta-catenin were negative.