Fine needle aspiration cytology in diagnosing tubercular mastitis: A rare entity with differential diagnoses and learning points.

INTRODUCTION: Extra-pulmonary tuberculosis occurring in the breast is a rarity. The clinical presentation is multifaceted, often mimicking malignancy and pyogenic breast abscess. Fine needle aspiration cytology (FNAC) is an essential component of the triple test in evaluating breast lumps.

METHODS: The present study is a retrospective analysis of 18 cases of tubercular mastitis (TM) over two years who underwent FNAC and were found to respond to anti-tubercular therapy on follow-up. Air-dried and alcohol-fixed smears were made and stained with May Grünwald Giemsa and hematoxylin and eosin stains. Special stains: Ziehl Neelsen (ZN), Gram, and periodic-acid Schiff (PAS) were done. In cases where pus was aspirated, material was sent for microbiological culture. For the Mycobacterium culture, Lowenstein-Jensen medium slants were employed.

RESULTS: All 18 cases were female in the age range of 13-59 years (mean 29.5 years). The majority were in the age bracket of 21-30 years. Frank pus was aspirated in 9 cases. Based on FNAC characteristics, cases were divided into three groups. Group I included 10, 55.6 % cases with epithelioid cell granulomas without necrosis. Group II had 6, 33.3 % cases showing epithelioid cell granulomas and necrosis, while Group III had 2, 11.1 % cases revealing caseous necrosis without any evidence of granulomas. The correlation of these groups to acid-fast bacilli (AFB) status showed AFB positivity of 100 % in group III, followed by 66.7 % in group II and 20 % in group I. Culture was positive for Mycobacterium tuberculosis in 5 cases.

CONCLUSION: FNAC is a preliminary diagnostic modality which avoids unnecessary surgical intervention for tubercular mastitis. Demonstration of epithelioid cell granulomas in breast aspirates, even without AFB positivity in endemic regions for tuberculosis, calls for a therapeutic trial of anti-tubercular therapy.