Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 9 1 2024 10 22 6 9 Katia Avila Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Karla López López Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. María Durand Muñoz Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Judith Domínguez Cherit Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. 2023 10 09 2024 06 08 Granulomatosis with polyangiitis is an ANCA-positive vasculitis primarily affecting small to medium-sized vessels, typically involving the lungs and kidneys. This article presents a remarkable case of a patient with an unusual pyoderma gangrenosum-like ulcer on the face and granulomatosis with polyangiitis.  A 28-year-old man, previously diagnosed with granulomatosis with polyangiitis presented at a dermatology clinic with a 6-month-old ulcer in the right preauricular region following a traumatic incident. A spindle biopsy revealed suppurative granulomatous dermatitis with secondary vascular damage, while cultures showed no signs of infection. The patient was subsequently treated with rituximab, leading to a positive clinical response. This case underscores the challenge of diagnosing this rare manifestation of granulomatosis with polyangiitis and suggests that rituximab could be a valuable treatment option.   https://crcp.tums.ac.ir/index.php/crcp/article/view/880 https://crcp.tums.ac.ir/index.php/crcp/article/download/880/623