Four Cases of Polyarteritis Nodosa Presenting Initially as Pain and Pitting Edema in Both Lower Extremities

Polyarteritis nodosa (PAN) has a broad spectrum of clinical presentation, since it affects small and medium-sized muscular arteries with microaneurysm formation, aneurysmal rupture with hemorrhage, thrombosis, and, consequently, organ ischemia or infarction. Although skeletal muscle involvement is well documented in patients with PAN, it can mimic more common diseases, and cause confusion and delays in diagnosis. PAN muscular involvement may have limited or early systemic forms with a benign course and excellent clinical response to corticosteroid therapy. Herein, we describe the clinical course and outcome of four unusual cases of PAN manifested by acute onset of pain and pitting edema in both lower extremities; in addition, we reviewed the relevant literature. (J Rheum Dis 2017;24:48-54)