Endocrine Abstracts

Introduction: The most frequently secreted hormone in pituitary adenomas is prolactin, but prolactin and growth hormone co-secretion are also seen at not an uncommon frequency. Co-secretion of growth hormone has also been reported after long-term follow up in the prolactinoma patients which well controlled with cabergoline therapy. In this case report, we aimed to discuss the results of cabergoline therapy in a case of co-secreting GH and prolactine with a normal IGF1 level and no acromegalic features at the beginning.

Case: A 58-year-old woman is diagnosed with a pituitary adenoma five years ago. She was being examined for hypoglycemic symptoms but the prolactin level was 82.6 ng/mL(1.2–29.9), pituitary MRI revealed a lesion of 6×5 mm in size and cabergoline treatment was started. After two years, the treatment was discontinued because the patient was asymptomatic, the lesion was shrinking and she was in the postmenopausal period. In the follow-up of third years, patient’s showed acromegalic features such as growth in hands and feet, thickening in fingers, in the laboratory examination IGF1 was normal, but growth hormone(GH) was not suppressed with OGTT. Since the size of the mass increased to 9×6 mm in pituitary MRI cabergoline treatment was started again. The pre-treatment IGF1 level was 323 ng/mL(81–225,the patient’s age group) at the highest, while the control visits were between 157 and 237 ng/mL. Post-treatment yearly MRIs revealed the mass size decreased to 7×7 mm and stabilized. Cabergoline therapy is planned to be continued due to the absence of significant symptom.

Conclussion: Co-secretion is usually seen in tumors with somatotrophs and mammotrophs together, mammosomatotrophic cell-derived tumors and acidophilic stem cell-derived tumors and usually acromegalic findings were at the beginning in the first two conditions. In the later, acromegaly is added shortly after the presence of the prolactinoma and these tumors are aggressive. Classically, the first treatment option for mixed tumors is surgical. However, cabergoline is effective in both prolactinoma and GH-secreting adenomas. In the present case, it seems that there is a progression in a milder level that can be controlled with cabergoline. Accordingly, it can be argued that some mixed pituitary tumors may be mildly progressive in nature, and in such cases, medical treatment may be an appropriate treatment option for these pituitary tumors with co-secretion of prolactin and GH.