Lupus Mastitis Manifesting as Extensive Calcification in the Retromammary Area: A Case Report

Lupus mastitis is a presentation of lupus panniculitis that involves subcutaneous fat in patients with systemic lupus erythematosus (SLE). Moreover, lupus mastitis is a rare condition that typically presents as a palpable breast mass. Here, we report the case of a 29-year-old woman with a prior diagnosis of SLE who presented with palpable lumps in both breasts. Imaging studies were performed, and mammography revealed extensive and bizarre calcifications, mainly in the retromammary area. US revealed large irregular calcifications with posterior shadowing, and breast MRI images exhibited diffuse irregular persistent rim enhancement in the retromammary area. An US-guided biopsy was performed to differentiate the condition from breast cancer and confirmed the diagnosis of fat necrosis, consistent with the pathological characteristics of lupus mastitis. Herein, we present a case of lupus mastitis, an unusual clinical manifestation of SLE, and discuss the clinical, pathological, and imaging findings supporting the diagnosis and the differential diagnosis.