Fine needle aspiration cytology in young women with breast cancer: diagnostic difficulties

Breast carcinoma is the most common malignancy in women worldwide. Though fine needle aspiration cytology (FNAC) plays an important role in preoperative diagnosis, there may be diagnostic delays in affected young women due to a lower index of suspicion.

The files of the Departments of Pathology, Singapore General Hospital, Singapore, and Prince of Wales Hospital, Hong Kong, were searched for cases of breast carcinoma in women aged 35 years or less. Those with prior FNA procedures comprised our study group. The FNA smears were reviewed and classified into five categories: inadequate, benign, equivocal, suspicious, malignant. The findings were correlated with subsequent histology.

Thirty-four women aged 35 years and below underwent 35 FNACs, with one woman having bilateral FNA procedures. Upon review, one (2.9%) was classified as inadequate, one (2.9%) benign, five (14.3%) equivocal, five (14.3%) suspicious, 21 (60%) malignant and slides were not available for review for two (5.6%) cases. For six benign and equivocal cytological diagnoses, subsequent histology disclosed pure ductal carcinoma in situ (DCIS, 1 case), mucocoele-like lesions with DCIS (2 cases), invasive and in situ ductal carcinoma with neuroendocrine features (1 case) and two cases of invasive ductal carcinoma.

Diagnostic difficulties in cytological interpretation of aspirates from breast carcinoma in young women may lead to unwanted delays, which occurred in six (17.6%) of 34 women in our series. Low grade cancers posing a pitfall in cytological diagnosis have to be considered.