Pure papillary carcinoma is rare in breast, although a papillary component may be present in up to 3-4% of breast carcinomas. It typically occurs in postmenopausal women.
FNA smears show three-dimensional papillary groupings of cells, some with fibro-vascular cores, with scattered columnar tumour cells and a bloody diathesis with haemosiderin-laden macrophages in the background. Nuclear atypia is often mild.
Cytological diagnostic features
- Moderate cellularity
- Three-dimensional papillary groups, fibro-vascular cores
- Atypical columnar cells
- Haemosiderin-laden macrophages
The differential diagnosis includes fibroadenoma, (favoured by the presence of finger-like branching without a fibro-vascular core and bipolar naked nuclei in the background), and papilloma. It is often very difficult to distinguish well-differentiated papillary carcinoma from benign papilloma, and surgical excision is advised when a papillary neoplasm is diagnosed by FNA cytology.