Abstract

Metastatic Crohn's disease (MCD) is a rare cutaneous manifestation of the well-known inflammatory bowel condition. It typically presents as intertriginous skin lesions in areas noncontiguous with the gastrointestinal tract and most commonly appears as sarcoidal type granulomas surrounded by mixed infiltrates, including lymphocytes and plasma cells. The development of these lesions may precede or follow the onset of gastrointestinal symptoms. Here, we present a 25-year-old female with a history of Crohn's disease who was evaluated for an ulcerated cutaneous nodule in the right thenar eminence of nine months duration. The lesion initially appeared as an itchy papule and was treated with antibiotics with no improvement. The excision specimen showed ulcerated skin with focal pseudoepitheliomatous hyperplasia and necrobiotic granulomas with elastophagocytosis, scattered neutrophilic microabscesses, langerhans and foreign body giant cells, lymphocytes, and plasma cells. PAS, Fite, and Gram stains were negative. Wound cultures grew skin flora, and mycobacterial cultures were negative. Given her clinical history of Crohn's disease, the findings were interpreted as a possible manifestation of MCD. 

Necrobiotic granulomatous inflammation has been very rarely reported in the setting of MCD. The histologic differential diagnosis includes other entities, such as granuloma annulare. Here we highlight the importance of a comprehensive clinical history, which was crucial in this case, given the unusual location and histologic appearance. An accurate diagnosis is essential as MCD lesions have variable responses to therapy and tend to recur locally.