Diagnosis of collagenous spherulosis of the breast by fine needle aspiration cytology. A report of two cases.

We describe the cytopathologic features of two cases of collagenous spherulosis of the breast on fine needle aspiration cytology. The main findings were a moderately rich cellular aspirate, monolayered epithelial clusters with bland nuclei, naked bipolar nuclei and light green (Papanicolaou stain) or pink (Diff-Quik) spherules surrounded by a ring of comma-shaped nuclei resembling myoepithelial cells, located either at the heart of the epithelial clusters or detached from them. We also comment on the differential diagnosis with adenoid cystic carcinoma of the breast, signet-ring carcinoma and myospherulosis.