Necrobiosis lipoidica with elastophagocytosis on an unusual location

摘要

Necrobiosis lipoidica (NL) is a granulomatous disease of collagen degeneration classically affecting the lower extremities. Elastophagocytosis is a histological finding, whereby multinucleate macrophages demonstrate phagocytosis of elastic fibers commonly associated with sun-damaged skin. Elastophagocytosis is not typically described in NL. The authors present a patient who presented with reddish-yellow plaques on both his forearms. Skin biopsy revealed extensive palisaded granulomas consistent with NL and features of elastophagocytosis in the upper dermis. The unusual site of presentation is a diagnostic pitfall, further complicated by the histological features of elastophagocytosis, for which the differential diagnosis of actinic granuloma needs to be considered. This case highlights the importance of clinicopathological correlation to arrive at a definitive diagnosis in situations where unexpected features on physical examination and histology may confound the clinical picture.