Case Report: Dermatomyositis with symmetrical axillary and inguinal panniculitis associated with anti-NXP-2

We report a rare case of dermatomyositis in a woman in her 60s, presenting with chronic pruritic erythema and symmetrical subcutaneous indurations in both axillae. Physical examination revealed Gottron’s papules and erythematous plaques on the hands and upper extremities. Laboratory tests showed mildly elevated serum CK, aldolase, and CRP levels. CT revealed increased fat density in both axillae, suggestive of panniculitis. Skin and subcutaneous biopsies confirmed interface dermatitis and panniculitis with membranocystic changes. After that, bilateral inguinal panniculitis developed. Autoantibody screening identified strong positivity for anti-NXP-2 and anti-Ki antibodies. Anti-NXP-2 antibody was further confirmed by immunoprecipitation-Western blotting. The diagnosis of dermatomyositis was made, and oral prednisolone (10 mg, 0.2 mg/kg/day) led to marked improvement. These findings may suggest a potential association between anti-NXP-2 antibodies and panniculitis.