Fine needle aspiration cytology of granulomatous mastitis: a study of 18 cases.

OBJECTIVE

To study fine needle aspiration cytologic features of granulomatous mastitis (GM), which can clinically mimic a carcinoma of the breast.

STUDY DESIGN

The aspirate was obtained using a 10-mL syringe and 22-gauge needle in 18 women. No smears were made, and material was collected as needle and syringe washings in a cytology container in which 30% ethyl-alcohol in physiologic saline was present. From about half of this material, filter preparations were made on 3-mm Schleicher and Schuell filters and stained by the Papanicolaou method; the remainder of the aspirate was spun, and a cell block was made from the sediment and sections cut and stained with hematoxylin-eosin (H-E).

RESULTS

The ages of the women ranged from 28 to 38 years, with a mean of 33 years, and time of last childbirth ranged from 4 to 7 years. Sixteen of the women had breast-fed for 6-15 months, and none were pregnant or breast-feeding at this time. The presenting symptom was a breast mass, left side (n=10) and right side (n=8). The diagnosis of GM was made on cytology and cell blocks of the aspirate and confirmed subsequently on stained tissue sections of the excised, operable lump in 12 of the cases. No organisms were found on microbiologic testing of aspirate and/or tissue sample, and stains for acid-fast bacilli and fungus were negative in sections of cell blocks and tissue in all cases. The cytohistologic features were characterized by noncaseating epithelioid cell granulomas with multinucleate giant cells, lymphocytes, plasma cells and a variable number of neutrophils along with inflammatory cell infiltrate in the interlobular and intralobular stroma.

CONCLUSION

GM, despite infrequent reporting but typical cytohistologic features, cannot only be diagnosed by the noninvasive method of fine needle aspiration cytology, but can also resolve the differential diagnosis between an inflammatory process and malignancy of the breast, which may not be possible alone on clinical and image-guided investigations.