Adenoid cystic carcinoma
Adenoid cystic carcinoma is a rare type of breast carcinoma, usually associated with an excellent prognosis and generally not resulting in lymph node metastases.
Its cytological features are identical to the ones of its more common salivary gland counterpart. The smears consist of nests of small uniform, basaloid cells that are intimately associated with metachromatically staining matrix, often forming three-dimensional spheres. Fragments of fibrillary stromal material, closely associated with the epithelial cells and the mucin-positive luminal material, can be present.
The differential diagnosis includes collagenous spherulosis, whose epithelial cells are bland-appearing and lack the nuclear atypia which may be present in adenoid cystic carcinoma