44 | extensive ulcerative-bullous lesions in a patient with granulomatosis with polyangiitis: A diagnostic challenge

Background. Granulomatosis with polyangiitis (GPA) is an ANCA-associated necrotizing vasculitis affecting small and medium sized vessels. Cutaneous manifestations include palpable purpura, papulonecrotic lesions, nodules and ulcerations. Extensive ulcerative-bullous involvement is uncommon and may represent a significant diagnostic challenge.Case Report. A 60-year-old man with longstanding GPA involving the kidneys, paranasal sinuses, nose, trachea and eyes, complicated by retinal vasculitis causing unilateral blindness, was admitted because of progressive skin lesions affecting both lower limbs. Previous treatments included cyclophosphamide and rituximab. His medical history was also significant for peripheral arterial occlusive disease, type 2 diabetes mellitus, arterial hypertension and hypogammaglobulinemia. Dermatological examination revealed widespread purpuric plaques, hemorrhagic bullae, necrotic areas and multiple deep ulcerations with fibrinous-necrotic bases. Culture from one ulcer yielded methicillin-sensitive Staphylococcus aureus (MSSA), and intravenous amoxicillin-clavulanate therapy was initiated, resulting in only partial clinical improvement. Although bacterial superinfection was documented, the morphology, distribution and severity of the lesions raised concern for active vasculitic disease or an alternative concomitant pathogenic process. The coexistence of GPA, peripheral arterial disease, hypogammaglobulinemia and secondary infection further complicated the diagnostic assessment. Therefore, repeat skin biopsy and direct immunofluorescence were performed and histopathological evaluation is currently ongoing.Discussion. Severe ulcerative-bullous lesions are an uncommon manifestation of GPA and may overlap clinically with ischemic ulcerations, pyoderma gangrenosum, infectious complications and other vasculopathic disorders. In this patient, multiple concurrent factors potentially contributing to tissue damage complicated attribution of the lesions to a single underlying mechanism. Careful integration of clinical, microbiological and histopathological findings is essential for accurate diagnosis.Conclusions. This case highlights the diagnostic complexity of extensive ulcerative-bullous lesions in a patient with GPA and multiple comorbidities. Recognition of overlapping pathogenic mechanisms and close clinicopathological correlation are crucial to guide appropriate management and therapeutic decision-making.