Extensive Vulvar Involvement as the Initial Presentation of Granulomatosis with Polyangiitis in a Young Woman.

Introduction: Granulomatosis with polyangiitis (GPA) is a rare systemic vasculitis, rarely affecting the genitourinary tract. Vulvar involvement is extremely uncommon and often misdiagnosed.

Case presentation: A 21-year-old female patient presented with a one-month history of necrotic vulvar lesions and skin ulcerations. Markedly elevated PR3-ANCA and histopathological findings supported the diagnosis of GPA. Imaging methods revealed multiple spleen infarctions and pseudo-masses in the kidneys; endocranial MRI showed pansinusitis and otomastoiditis. Initial treatment with systemic corticosteroids and methotrexate was insufficient; however, rituximab achieved significant improvement, resulting in complete healing of both vulvar and skin lesions.

Conclusion: Vulvar GPA, though rare, may be the initial sign of systemic vasculitis. Multidisciplinary evaluation is important for early diagnosis and effective immunosuppressive therapy.