[Atypical decubitus fibroplasia: a recent entity. Apropos of a case of an adolescent girl].

Atypical decubital fibroplasia (FAD) occurs especially in elderly and physically debilited or immobilized patients. We report one observation which is peculiar due to the patient's young age and its circumstances. The painless mass is situated in hyperpressure areas (shoulder, posterior or lateral chest wall, sacrum). The lesion is situated in the deep subcutis and has ill defined limits; it is characterized by zones of fibrinoid necrosis and fibrosis and a prominent myxoid stroma. The differential diagnoses includes mesenchymatous malignant tumors and non neoplastic fibroblastic proliferations such as proliferative fasciitis and decubitus ulcer. The prominent underlying factor and the initial event contributing to its pathogenesis seems to be ischemia. Although some recurrent cases have been reported, FAD is a benign lesion whose treatment is surgical removal.