Growth Hormone and Prolactin Co-secreting Pituitary Adenoma: a Case Report and Review of Literature

Co-secreting growth hormone and prolactin pituitary adenomas, which comprise a considerable portion of all growth hormone-secreting adenomas, can be characterized into three distinct subtypes. In this report, we present a case of a monomorphous mammosomatotroph cell adenoma successfully treated with transsphenoidal surgical resection. A 38-year-old female presented to clinic with a 1-year history of galactorrhea and oligomenorrhea. This was on the background of a 4-year history of insulin intolerance and acromegaly, notably of the hands and feet. At the time of presentation, the patient had a reported body mass index (BMI) of 34.28 kg/m 2 and an elevated blood pressure (BP) of 128/78 mmHg. It was suspected at this stage that the patient had a growth hormone (GH) and prolactin (PRL) co-secreting pituitary adenoma. Head MRI confirmed the presence of a pituitary adenoma measuring 1.0 × 1.2 × 1.3 cm. Clinically, the sequence of symptoms suggested a monomorphous mammosomatotroph cell adenoma, with definitive diagnosis requiring an oral glucose tolerance test (OGTT) and histological tissue sampling for tumor typing. Transsphenoidal surgery (TSS) is indicated for symptomatic microadenomas and non-invasive macroadenomas. A TSS approach was recommended despite the patient’s relatively small-sized tumor. Though it was not required for our patient, adjuvant therapy such as octreotide and cabergoline may be implemented post-operatively to prevent recurrence and, in the case of residual tumor, radiosurgery or additional surgical resection may be implemented for symptomatic relief. At this time, however, research proving the effectiveness of medical therapy over TSS for the treatment of monomorphous mammosomatotroph adenomas is lacking. For those who are unable to undergo surgery, more work is needed in this field to determine the effectiveness of medical treatment for this specific type of tumor.