Re-emphasising the importance of catheter-based angiography to differentiate polyarteritis nodosa from cutaneous arteritis: Two case reports.

Polyarteritis nodosa (PAN) is a systemic necrotising vasculitis with a poor prognosis, characterised by inflammation and necrosis of medium-sized arteries. PAN patients can present with a wide range of systemic manifestations, whereas cutaneous arteritis (CA) is a restricted manifestation to skin of the disease with a more favourable prognosis. Thus, differentiation between PAN and CA is crucial. Here, we present two cases that were initially diagnosed as CA due to the limited presence of systemic symptoms, but were finally diagnosed as PAN through catheter-based angiography. Although contrast-enhanced computed tomography and computed tomographic angiography are increasingly used to diagnose PAN, neither case had any abnormal findings on these examinations. Our cases therefore underscore that catheter-based angiography is critical for differentiation between PAN and CA, even in cases with limited systemic symptoms.