Pyodermatitis-pyostomatitis vegetans: report of a case and review of the literature.

Pyodermatitis-pyostomatitis vegetans is a benign, rare disorder characterized by a pustular eruption in the oral mucosa and vegetating plaques involving the groin and axillary folds. Its association with inflammatory bowel disease is well established. We report the case of a 49-year-old-white man with ulcerative colitis who manifested a vegetating, annular plaque in the left inguinal region of 2 months' duration. Oral examination disclosed an erythematous mucosa with multiple painful pustules involving the labial and gingival mucosa. Histopathologic study demonstrated epidermal hyperplasia and an inflammatory infiltrate composed mostly of neutrophils and eosinophils, grouped into microabscesses within the epidermis and with a bandlike configuration in the upper dermis. Results of direct and indirect immunofluorescence studies were negative. We discuss the differential diagnosis between pyodermatitis-pyostomatitis vegetans and pemphigus vegetans.