Atypical decubital fibroplasia: a series of three cases.

We report three cases of atypical decubital fibroplasia (ADF), a benign, reactive pathologic process that develops in the skin and subcutaneous tissue of immobilized or debilitated patients. Two patients were immobilized, one wheelchair bound, and one bedridden. The third patient frequently lay over the affected area. Two were male, one female, ages 49, 66, and 89 (mean 68 years old). Each patient presented with a subcutaneous mass, one with focal surface ulceration, present for 5 months, 6 months, and 12 months (mean 7.7 months). The locations included back, lateral thigh (over greater trochanter), and lateral chest wall. No other lesions were present, and none had recurrences. Histologically, atypical decubital fibroplasia is characterized principally by dermal and subcutaneous tissue involvement with fibrinoid necrosis, reactive fibrosis, and focal myxoid change with surrounding more cellular zones of prominent reactive neovascularization including granulation tissue and ectatic vessels with reactive atypical fibroblasts and fat necrosis. Other findings include hyalinization of vessel walls, fibrin thrombi, red blood cell extravasation, hemosiderin deposition, and acute and chronic inflammation. Although the changes are predominantly deep, involving the dermis, subcutaneous tissue and skeletal muscle, the overlying epidermis may ulcerate. Recognition of atypical decubital fibroplasia is of paramount importance, for it may be misinterpreted as a sarcoma, both clinically and histologically.