Magnetic resonance enterography showed terminal ileitis and colonoscopy revealed a strictured ileocecal valve, with oedema and nodular appearance, and terminal ileitis with cobblestone mucosa. Polymerase chain reaction for the detection of the Mycobacterium tuberculosis complex in ileal mucosa was negative. Skin biopsy demonstrated dermatitis with a granulomatous pattern, with secondary ulceration and dermal fibrosis (Figs. 2-4). No fungal microorganisms or acid-fast bacilli were identified with the Periodic Acid-Schiff stain and Ziehl-Neelsen techniques.What is the most likely diagnosis?