A 35-year-old man with long-standing ulcerative colitis for 12 years presents with painful, rapidly progressive ulcerating skin lesions on the lower legs. The lesions have violaceous undermined borders. Which extraintestinal manifestation is this, and what is its characteristic histopathological finding?
- A Erythema nodosum; septal panniculitis without vasculitis
- B Erythema multiformum; interface dermatitis with necrotic keratinocytes
- C Pyoderma gangrenosum; neutrophilic infiltrate with sterile abscess formation ✓
- D Cutaneous polyarteritis nodosa; transmural necrotizing vasculitis of small arteries
Correct answer: C. Pyoderma gangrenosum; neutrophilic infiltrate with sterile abscess formation
Explanation
Pyoderma gangrenosum presents as painful ulcers with violaceous undermined borders, classically on the lower extremities, and is associated with IBD. Histology shows dense neutrophilic infiltrate with sterile abscess formation. Erythema nodosum presents as tender subcutaneous nodules with septal panniculitis, not ulcerating lesions. The undermined violaceous border is pathognomonic for pyoderma gangrenosum.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.