RESUMEN
Papillary lesions of the breast pose diagnostic challenges on aspiration cytology due to overlapping features of benign and malignant entities. Accurate cytologic diagnosis of papillary breast carcinoma cannot usually be made pre-operatively. We present the case of an adult female who underwent fine-needle aspiration (FNA) of a left breast lump. FNA smears were highly cellular showing cohesive clusters, complex papillary fragments and few singly dispersed intact cells. The tumor cells had hyperchromatic nuclei, prominent nucleoli and mild nuclear pleomorphism. A cytologic impression of papillary lesion, possibly malignant (in view of high cellularity, complex papillae and single intact cells) was rendered. The lesion proved to be a papillary carcinoma with microscopic foci of stromal invasion on histologic examination. Papillary carcinoma, an uncommon subtype of breast carcinoma, should be considered while evaluating a papillary lesion with complex branching papillae containing delicate fibrovascular cores and singly lying intact atypical cells.