Lactotroph adenomas, also called
prolactinomas and
prolactin-secreting
adenomas, constitute nearly 80% of functioning
pituitary tumors and about 30-50% of all
adenomas in the clinical practice.
Lactotroph adenomas occur in the general population at a prevalence of 45/100,000, are more common in women, but also involve men and children of both sexes. Most
lactotroph adenomas are microadenomas occurring in reproductive-age women who present with oligo/
amenorrhea,
galactorrhea, and
infertility. In men and elderly women,
lactotroph adenomas are usually macroadenomas and are most commonly associated with symptoms of a tumoral mass, including
headaches, neurologic defects, and visual loss. Although clinical and laboratory features may differ depending on patient's gender and age, the histopathology of the
tumors is similar.
Lactotroph adenomas are histologically classified into three subtypes: the common sparsely granulated
lactotroph adenoma, and the rare densely granulated
lactotroph adenoma and acidophilic stem cell
adenoma. We will review the main pathological features of the
lactotroph adenomas and some of their characteristics that may predict biological behavior and responsiveness to treatment.