A solid hypocellular proliferation of spindle cells are seen in a wavy collagenous background.
The cells with larger nuclei may be scattered atypical cells or giant cells, the latter of which tend to line the pseudovascular cleft like spaces.
Giant cell fibroblastoma is a fibroblastic tumor located in the dermis and subcutis. It exhibits the same translocation seen in dermatofibrosarcoma protuberans - t(12;22)(q22;q13). It is also CD34 positive as is DFSP.
Histologically, a proliferation of spindled or stellate fibroblasts is seen in the dermis or subcutis. The lesion is poorly circumscribed. Characteristic features are "angiectoid" spaces, which are pseudovascular sinusoidal spaces without a true endothelial lining, and the presence of multinucleated giant cells. These multinucleated cells may have a floret arrangement and often line the angiectoid spaces.
Giant cell fibroblastoma mainly affects boys in their first decade of life. Common locations include the trunk and lower extremities. It is considered by some to be the pediatric version of adult DFSP while others consider them similar but not the same entity.
Excision is the mainstay of treatment. Up to 1/3 of lesions may recur if not completely resected.
→Same translocation as seen in DFSP - t(17;22).
→Affects young boys whereas DFSP is seen in adults of either sex.
→Tumor backgrounds may vary from solid and collagenized to angiectoid and myxoid
Fletcher CDM, ed. Diagnostic Histopathology of Tumors. 3rd Ed. Philadelphia, PA: Elsevier; 2007: 1487-8.
Jha P, Moosavi C, Fanburg-Smith JC. Giant cell fibroblastoma: an update and addition of 86 new cases from the Armed Forces Institute of Pathology, in honor of Dr. Franz M. Enzinger. Ann Diagn Pathol. 2007 Apr;11(2):81-8.