Granulomatous inflammation of the breast in a pregnant woman: report of a case with fine needle aspiration diagnosis

BACKGROUND: Granulomatous inflammation of the breast is an inflammatory process with multiple etiologies. It can accompany breast carcinoma or be idiopathic. It often presents clinically in a fashion mimicking carcinoma. Idiopathic granulomatous mastitis is strongly associated with lactation and is reported to occur in postpartum patients. This is the second fine needle aspiration (FNA) report of idiopathic granulomatous inflammation in the breast of a pregnant woman. CASE: A 27-year-old, 7-month-pregnant woman presented with a hard nodule in her right breast; on ultrasound examination it showed mixed echogenicity, suspicious for carcinoma. FNA showed granulomatous inflammation. The smears were highly cellular, with many clusters of and single epithelioid cells displaying moderate pleomorphism and prominent nucleoli in a background composed of neutrophils, plasma cells, lymphocytes and multinucleated cells. Core needle biopsy revealed a nonnecrotizing, granulomatous lesion. CONCLUSION: The diagnosis of granulomatous inflammation can be challenging, and the cytologic features can be difficult to separate from those of carcinoma. The relatively rare occurrence of this lesion and its cytologic features make it a potentially difficult diagnosis and diagnostic pitfall.