PSD01 Superficial pyoderma gangrenosum of the penis

Abstract

A 74-year-old man with a history of rheumatoid arthritis was admitted with urinary retention and painful ulceration of his penis. His rheumatoid arthritis was controlled with methotrexate and baricitinib. There was new-onset ulceration extending from his prepuce along the ventral shaft and expanding over his scrotum, beginning in the last week and extended rapidly. It had a violaceous border with yellow adherent slough. It was extremely painful and the patient was avoiding fluid intake to minimize urination and manipulation. The foreskin could not be retracted. He incidentally had a cold sore on his upper cutaneous lip. A biopsy was performed, which demonstrated ulceration mixed with areas of parakeratosis with fibrinous exudate and extensive regenerative change. Pyoderma gangrenosum was suspected. He was commenced on prednisolone 0.5 mg kg−1 and topical clobetasol propionate, with nonadherent dressings and paraffin gel. A viral swab later returned with a low level of herpes simplex virus (HSV)1 DNA. Management was changed to aciclovir. At the 2-week review the ulceration had resolved by 70%. However, the ulcer still had an active inflammatory edge. Pain persisted and the foreskin could still not be retracted. The patient was admitted for a circumcision. A repeat swab did not detect any HSV. Histology from the foreskin demonstrated ulceration with granulation tissue and no neoplastic changes. No pathogens were cultured. The ulcerated area was treated with clobetasol propionate and resolved over the course of 4 weeks. The patient was diagnosed with superficial pyoderma gangrenosum on a background of rheumatoid arthritis. Furthermore, no viral inclusion bodies were detected on histology. It is suspected that the low level HSV titre was not the main cause for ulceration. The detection may have been due to contamination from his perioral HSV. The case highlights the atypical and dramatic appearance of superficial pyoderma gangrenosum and the differentials in an immunosuppressed individual.