Breast tumors in patients with hyperprolactinemia.

The histology of breast lumps in five patients with hyperprolactinemia showed benign mammary dysplasia with vacuolation of acinar and duct lining cells. In two cases, foci of lobular development resembling lactating breast tissue were also noted. In the past, focal secretory change has been considered to be idiopathic, but these cases indicate a possible association with hyperprolactinemia. Among other causes hyperprolactinemia may be a manifestation of occult pituitary adenoma. Therefore it is suggested that patients with benign breast nodules showing focal secretory change should be screened for clinical and laboratory evidence of hyperprolactinemia. Although it is accepted that in mice and rats prolactin plays an important role in chemically induced mammary tumorigenesis, a consensus has not been reached with regard to its role in man.