Polyarteritis nodosa (PAN) is a necrotizing vasculitis predominantly affecting medium-sized muscular arteries, characterized by transmural inflammation, fibrinoid necrosis, and subsequent ischemic tissue injury [1], [2]. PAN lacks anti-neutrophil cytoplasmic antibody (ANCA) positivity and does not involve arterioles, capillaries, venules, or glomeruli, allowing its distinction from other systemic vasculitides [3]. PAN remains a clinically heterogeneous disease with variable patterns of organ involvement [4]. Classically, PAN presents as a multisystem disease, most frequently involving the skin, peripheral nerves, gastrointestinal tract, kidney, and musculoskeletal system [5].

In contrast, isolated or single-organ PAN represents a distinctly rare and under-recognized clinical entity [6]. Available literature suggests that isolated organ PAN may follow a more benign course than systemic PAN, with a low likelihood of progression to multisystem disease after surgical resection of the affected organ [3], [6], [7], [8]. Isolated PAN most commonly involves the testis, urinary bladder, skin, or gastrointestinal tract, often mimicking neoplastic or acute surgical conditions, and leading to organ resection before a vasculitic diagnosis is established [6], [8], [9], [10], [11].

Surgical resection as a result of PAN involvement in an organ remains exceedingly rare, and published data are largely limited to isolated case reports or small observational cohorts. The aim of this study is to highlight shared clinicopathological features and diagnostic patterns in patients with polyarteritis nodosa presenting as isolated genitourinary organ involvement requiring surgical resection, based on a multicenter pathology-based analysis.