Nonhemophiliac musculoskeletal pseudotumor

A 24-year-old man presented with impending ulceration of a large thigh swelling which appeared after minor trauma. Imaging revealed a large well-encapsulated lesion with no vascularity. He was diagnosed to have a pseudotumor and underwent successful excision of the mass under blood and cryoprecipitate cover. The unusual presentation was suspected to be secondary to a transient drug-induced factor XIII deficiency because the result of the final coagulation study was normal.