Lactational adenoma: A diagnostic pitfall on fine needle aspiration cytology

Abstract

Pregnancy induces hormone‐related breast changes which pose diagnostic challenges in the evaluation of a
breast lump. In particular, fine needle aspiration cytology of a lactating adenoma may mimic malignancy. The
authors present a case of a woman with a right breast lump. Fine needle aspiration cytology demonstrated
the presence of numerous single‐occurring epithelial cells with large round nuclei, discrete nucleoli, and
ample vacuolated cytoplasm. Taken in isolation, this finding would be suspicious for malignancy. However,
the clinical history of recent pregnancy was duly noted as was the presence of a granular vacuolated
background on cytology. An accompanying core biopsy confirmed the lesion to be a lactating adenoma.
This case highlights lactating adenoma as a potential diagnostic pitfall on fine needle aspiration cytology.