Cytologic findings from a nipple discharge in an infant with premature telarche

Premature telarche is a condition of isolated unilateral or bilateral breast development without additional signs of sexual maturation in girls primarily under 2 yr of age presumably occurring as a response to hormonal stimulation by estrogens. Prior reports concerning pathologic findings in premature telarche have been scarce. We report the cytologic findings from a nipple discharge in a 10-mo-old girl with unilateral breast enlargement due to premature telarche. The discharge showed an increased number of clusters of breast ductal epithelium, with a few in a papillary configuration. There was a moderate degree of nuclear irregularity in the epithelial cells, but no significant nuclear overlapping. No atypical single cells were present, and a rare myoepithelial cell was noted. These cytologic findings are in accord with a prior study describing the histology in three cases of premature telarche.