Author(s): Tomohiro Kawaguchi1 , Yoshikazu Ogawa1 and Teiji Tominaga2
Hyperprolactinemia has been associated with a large number of etiologies, such as certain medication, autoimmune disease, and sellar tumors. Pituitary adenoma is one of the most frequent causes of hyperprolactinemia, and prolactinoma accounts for a high proportion of hyperprolactinemia due to prolactin overproduction and oversecretion. Non-functioning pituitary adenoma is another etiology of hyperprolactinemia, which is induced by compression of the pituitary stalk.
Medical treatment with dopamine agonists (DAs) is highly effective for most cases, so that is widely accepted as the first line of treatment for hyperprolactinemia. In spite of the strong suppression of serum prolactin level, DAs usage has several disadvantages when used for patients with prolactinoma. Intolerance and residence have been reported in some patients [1, 2], and DAs are reported as a potential predisposing factor for pituitary apoplexy . For the pregnant patients, less data is available about the effects of continuous DAs usage on fetal development [4, 5]. Furthermore, DAs can normalize the serum prolactin level in patients with non-functioning pituitary adenoma presented with hyperprolactinemia by inhibition of the normal pituitary function, but there is no chance for tumor regression. So surgical treatment can be a considerable treatment option for some patients with large pituitary adenoma presented with hyperprolactinemia.
To decide the treatment options, discrimination of the cause for hyperprolactinemia is important. Small tumors presented with hyperprolactinemia could be considered prolactinoma in majority of the cases, so that it is not so difficult making correct diagnosis. However, differential diagnosis of large non-functioning pituitary adenoma and prolactinoma is sometimes very difficult despite several endocrinological loading tests and radiographical assessments have been evaluated . Although recent reports indicated the endocrinological discrimination of non-functioning pituitary adenoma from prolactinoma, the cut-off value of serum prolactin concentration between them varied widely from 94 to 200 ng/ml and there are no definitive diagnostic criteria [6-8].
In this study, we retrospectively reviewed the patients with prolactinoma and non-functioning pituitary adenoma presented with hyperprolactinemia to confirm whether the serum prolactin cut-off value is definitive to distinguish them. The characteristics of clinical course and management for these patients were discussed.
We retrospectively reviewed patients with non-functioning pituitary adenoma, including gonadotroph cell adenoma and null cell adenoma, and prolactinoma who were surgically treated at Kohnan hospital between June 2005 and March 2012. Most patients with prolactinomas were referred from the endocrinological or gynecological clinics. During this period, 724 cases were treated with transsphenoidal surgery, performed by single surgeon (Y.O.). Among them, 95 (13.1%) patients with prolactinoma and 212 (29.3%) patients with non-functioning pituitary adenoma were analyzed.
Surgical indication for prolactinoma
Surgery was indicated for the patients who required skull base reconstruction to prevent cerebrospinal fluid leakage, and who already presented severe visual disturbance. Patients with small tumor without endocrinological and neurological symptoms were not included. Otherwise, we propose both medical treatment and surgery as treatment options. The advantage and disadvantage of them were equivalently explained. Surgery was performed for patients who understood...