PROLACTIN-PRODUCING PITUITARY-ADENOMA IN A MALE-TO-FEMALE TRANSSEXUALPATIENT WITH PROTRACTED ESTROGEN ADMINISTRATION - A MORPHOLOGIC STUDY

Pituitary adenoma developed in a 33-year-old male-to-female transsexua l patient who was given estrogen, starting at 16 years of age; the pit uitary adenoma was surgically removed and studied by light microscopy, immunocytochemistry, and in situ hybridization. The adenoma cells wer e immunoreactive for prolactin, and exhibited a strong signal for prol actin and estrogen receptor messenger RNAs and a weak signal for dopam ine receptor messenger RNA. The question of whether the development of an adenoma was incidental or was the direct effect of estrogen or whe ther it was mediated via other mechanisms, such as activation of growt h factors or oncogenes or inhibition of tumor-suppressing genes or oth er genetic abnormalities, remained unresolved. The present case, which , to our knowledge, is the first to describe structural findings of a pituitary adenoma in a transsexual patient who was given estrogen, rei nforces the view that protracted stimulation may play a role in the ge nesis of endocrine tumors.