A Rare Case of Granulomatous Mastitis Associated With Positive Systemic Lupus Erythematosus Serology in a Young Female Patient: A Case Report and Literature Review.

Granulomatous mastitis (GM) is a rare benign breast disease that affects women of childbearing age, usually within five years of pregnancy. The hallmark diagnostic feature of GM is the presence of lobular granulomatous inflammation. The occurrence of this clinicopathological entity is usually idiopathic. Nevertheless, GM has often been associated with systemic inflammatory conditions of either infectious (such as tuberculosis) or autoimmune etiology (particularly sarcoidosis, vasculitis, and less likely systemic lupus erythematosus [SLE]). In this report, the authors described an unusual case of GM that was associated with features of SLE in a young female patient who presented with a painful breast lump. Histopathological examination of the lump's biopsy showed GM. Further laboratory workup revealed evidence of some immunological criteria of SLE. Steroid therapy led to the resolution of the patient's breast swelling. The breast mass remained in remission with hydroxychloroquine treatment. Only a handful of similar cases in the current literature demonstrated a plausible association between SLE and GM. Our case provides a reference to consider SLE as a possible differential diagnosis when GM is encountered in young-aged female patients.