Following these negative results, the patient was transferred for further investigation. In view of the continuing fever and after consideration of the radiological findings, it was decided to resect the lesion. A 3.5 x 4 cm hard, although not well circumscribed, mass invading fat was excised. There was an overlying long saphenous vein. CT scan of the left thigh, showing rounded lesion in the subcutaneous tissue with feeding vessels in relation to the mass.
Temperature chart before and after surgical excision of the pseudotumor.
There were focal areas of hemosiderin deposition. The picture was consistent with an inflammatory pseudotumor. The etiology of these tumors is not known but they may represent an unusual inflammatory response to precipitating factors such as surgery, trauma and localized infection. This is supported by the fact that the spindle cells in the lesion are actually myofibroblast cells that are found in granulation and scar tissue, and hence they may be representative or an unusual variant of the inflammatory response. The sites most frequently reported in the literature to be involved in pseudotumor formation include lung, liver, intestine and stomach.