Superficial Granulomatous Pyoderma

Abstract
Superficial granulomatous pyoderma (SGP) is a rare variant of pyoderma gangrenosum (PG) characterized by superficial ulcers with vegetative or crusted borders and cribriform scars, mixed suppurative, granulomatous and lymphoplasmacytic inflammation, in the absence of associated systemic diseases and responsive to steroid sparing therapy. Similar to classic PG, SGP is associated with pathergy. Clinical and histopathological recognition of this unique variant is important given its benign course and responsiveness to steroid sparing agents including systemic anti-inflammatory therapies. We present three cases of SGP. The first case involved a 32-year-old man with hidradenitis suppurativa who presented with an erythematous, ulcerated plaque on the upper back. The second case involved a 21-year-old female with ulcerative colitis, who presented with chronic, painful lesions on the back. The third case involved a 48-year-old man with a long history of painful, draining, vegetative plaques on the trunk without underlying systemic disease. Histology revealed mixed dermal suppurative, and granulomatous inflammation with eosinophils and plasma cells. Infectious workup was negative, and all responded to systemic steroid-sparing agents. PG is a clinical diagnosis; however, the superficial granulomatous variant is supported by defined histopathologic findings. While it is thought to have an indolent course, one patient had underlying systemic immune-mediated disease; therefore, full clinical workup is encouraged. Excision is associated with lesion extension and recurrence. Early recognition should militate against surgical intervention. Our cases highlight the protean clinical presentations, potential association with immune-mediated systemic diseases and distinct pathologic findings that respond to steroid sparing therapy.

Financial Disclosure:
No current or relevant financial relationships exist.

Published in: ASDP 59th Annual Meeting, USA

Publisher: The American Society of Dermatopathology
Date of Conference: October 17-23, 2022