Granulomatous mastitis: A diagnostic challenge-3 year single institutional experience.

Abstract

Granulomatous mastitis (GM) is often clinico-radiologically misdiagnosed as breast malignancy. Tuberculosis, foreign body reactions, fungal and parastic infections, and autoimmune diseases can cause GM. The present study aimed to assess the spectrum of GM on fine-needle aspiration biopsy (FNAB) smears along with its histopathological and clinico-radiological findings. It was a retrospective study which included all cases of GM diagnosed onFNABover a period of 3 years. The histopathological diagnosis was retrieved, wherever possible. All the FNA smears and histopathological sections were reviewed for the presence of epithelioid granulomas, necrosis, epithelioid histiocytes, inflammatory cells including plasma cells, neutrophils, eosinophils, multinucleated giant cells, and epithelial component and associated atypia, if any. The inflammatory cells and multinucleated giant cells were graded on a scale of 0 to 3+ in every case. Among the 22 cases evaluated, the most common inflammatory infiltrate was lymphocyte followed by neutrophils and eosinophils. Caseous necrosis was appreciated in 7 (31.8%) cases, out of which 5 (22.7%) were diagnosed as tubercular mastitis on FNA smears. Ziehl Neelson stain was done in all FNAB smears and AFB was positive in 7 (31.8%) cases. Histopathological correlation was available for 14 cases (63.6%). The most common diagnosis on histopathology was idiopathic GM having lobulo-centric granulomatous inflammation, epithelioid histiocytes, neutrophils, and lymphocytes. FNAB is a reliable and minimally invasive tool to diagnose tubercular mastitis, idiopathic GM and also ruling out clinicoradiological suspicion of malignancy. Careful examination of cytological smears can prevent an unnecessary biopsy in granulomatous lesions of breast.