Background: Polyarteritis nodosa (PAN) is a vasculitis that affects medium-sized arteries. PAN is a rare disease and requires a high clinical suspicion for diagnosis. PAN and HSP (newly named Immunoglobulin A-associated vasculitis) have narrowing differential diagnosis. Here, we reported a case of PAN. Case presentation: Our patient was a 65-year-old woman that came to hospital due to abdominal pain and skin lesion on the right upper and right lower extremities. All rheumatologic tests were negative. A biopsy of the skin lesion was reported as mild hyperkeratosis, slight spongiosis with intact basal layer. The dermis showed moderate to severe perivascular PMN infiltration with vessel wall degeneration and extravasation of RBCs. A colonoscopy reported diffuse mucosal erythema and erosions were seen in the rectum until 6cm of anal verge. An electromyogram test and nerve conduction velocity study of the upper extremities reported bilateral mild carpal tunnel syndrome, and in the right lower extremities mononeuritis multiplex could not be ruled out. Abdominopelvic CT scan reported diffuse wall thickening of terminal ileum associated with mesenteric fat and narrow enhancement of inferior Mesenteric artery with patchy filling defect. After evaluation, the patient received corticosteroid pulses plus cyclophosphamide. Conclusion: Diagnosis and treatment of PAN are important and PAN should be considered in a patient with skin lesions and neurological impairment.

Polyarteritis nodosa (PAN) is a vasculitis that affects medium Background: sized arteries. PAN is a rare disease and requires a high vilgilance for diagnosis. For instance, PAN and Henoch-Schonlein purpura (HSP) have narrowing differential diagnosis. Here, we report a case of PAN.Our patient was a 65 year old woman that came to Case presentation: hospital due to abdominal pain and skin lesion on the right upper and right lower extremities. All rheumatologic tests were negative. A biopsy of the skin lesion was reported as mild hyperkeratosis, slight spongiosis with intact basal layer. The dermis showed moderate to severe perivascular PMN infiltration with vessel wall degeneration and extravasation of RBCs. A colonoscopy reported diffuse mucosal erythema and erosions were seen in the rectum until 6cm of anal verge. An electromyogram test and nerve conduction velocity study of the upper extremities reported bilateral mild carpal tunnel syndrome, and in the right lower extremities mononeuritis multiplex could not be ruled out. Abdominopelvic CT scan reported diffuse wall thickening of terminal ileum associated with mesenteric fat and narrow enhancement of inferior Mesenteric artery with patchy filling defect. After evaluation, the patient received corticosteroid pulses plus cyclophosphamide.Diagnosis and treatment of PAN is important and PAN should be Conclusion: considered in a patient with skin lesions and neurological impairment.