Trisomy 4 in a case of gynecomastia.

Gynecomastia is an anomaly associated with alterations in the levels of hormones, especially estrogens. Sufferers of gynecomastia present a high risk of developing carcinomas. Only two cytogenetic descriptions of this type of mammary proliferation are available. In the present study, we analyzed chromosomally a sample of breast tissue from a patient with gynecomastia following short-term culture. The only clonal chromosomal alteration encountered was trisomy of chromosome 4. This alteration has not been described previously for samples of gynecomastia or breast cancer in males. We believe that the alterations in hormone levels in the male breast tissue that lead to this type of cellular proliferation induce the formation of chromosomal abnormalities, making the cells more susceptible to becoming malignant.