Spontaneous development of hyperprolactinaemia.

Spontaneous development of hyperprolactinaemia was investigated by measuring prolactin levels in 34 hyperprolactinaemic females with a normal sella turcica, in 19 females with a radiologically proven prolactinoma, and in 19 females with a histologically proven prolactinoma after transsphenoidal surgery. Prolactin levels remained unchanged or declined in 69 patients followed over a period of up to 6 years. In one patient with a normal sella turcica, prolactin levels increased accompanied by the development of a radiologically detectable microprolactinoma. In one patient with a radiologically proven macroprolactinoma the increase of human prolactin (hPrl) levels was accompanied by infiltrative and parasellar prolactinoma growth. One patient showed a dramatic increase of post-operative persisting elevated hPrl levels without radiological changes. These findings suggest that prolactinomas in general have a limited growth potential which should be considered in the management of hyperprolactinaemic patients.