Aggressive papillary male breast carcinoma on fine-needle cytology sample

Papillary carcinoma (PC) is a histological variant of breast carcinoma that is more frequently observed in males than in females, showing the same cytological features in both sexes. PC is characterized by a low grade of malignancy and a generally favorable course. We describe a case of male breast PC (MPC) diagnosed by fine-needle cytology (FNC) in which some aggressive morphologically detectable features were associated with bland cytologic features of the tumor. FNC was performed on a 3 cm palpable mass of the left breast of a 55-yr-old male. FNC yielded abundant bloody material. Two smears were Diff-Quik and Papanicolaou stained, others were used for immunocytochemical assessment of estrogen, progesterone, c-erbB-2, and Ki-67; another was Feulgen stained for DNA ploidy. Smears were highly cellular, showing isolated cells and papillary structures. Cells showed tall and well-defined cytoplasm with a columnar aspect, light anisonucleosis, coarse chromatin, and small nucleoli. Immunoperoxidase staining demonstrated positivity for estrogen (50%), negativity for progesterone, intense positivity for c-erbB-2, with specific membrane staining and positivity for Ki-67 in more than 20% of the cells. DNA-ploidy showed an aneuploid histogram with 5c exceeding rate (5cER) of 59% and 2c deviation index (2cDI) of 29%. Subsequent surgical pathology examination confirmed the cytological diagnosis of papillary carcinoma; moreover, it revealed neoplastic endolymphatic thrombi and infiltrative border of the tumor that reached the thoracic wall. Cytological features can suggest diagnosis of MPC on FNC samples. Immunocytochemical evaluation of c-erbB-2 and Ki-67 and DNA ploidy evaluation on cytological smears might reveal a biological aggressiveness of PC despite the bland microscopic features of the tumor and this should influence the therapeutic procedure.