The cytological diagnosis of metastases to the brest from extramammary malignancies; a cytomorphologic study with emphasis on ancillary techniques

Abstract

Metastatic neoplasm to the breast is a rare and heterogeneous event which can mimic primary breast carcinoma or benign neoplasm. Distinguishing metastasis from primary breast carcinoma is very important because of the difference in treatment options. This study aimed to investigate the diagnostic utility of fine-needle aspiration biopsy (FNAB) in differentiating breast metastases from primary breast neoplasm. FNAB of 50 metastases to the breast were evaluated for the following: cytomorphology, influence of clinical history and adjunctive methods on the final diagnosis. Reliable cytological criteria of malignancy were found in all 50 smears. These criteria, correlated with clinical data or complemented by ancillary techniques in selected cases, allowed correct diagnosis in 48 patients. Of the remaining two cases, wrongly diagnosed as primary carcinoma, one patient presented with a breast mass and the other had a history of intestinal carcinoid. FNAB plays an important role in the separation of metastatic neoplasm in the breast from primary breast carcinoma. Recognition of unusual cytomorphologic patterns, awareness of patient history and, in selected cases, ancillary techniques, are necessary in rendering a correct diagnosis of breast metastasis in FNAB smears.