Plurihormonal ACTH-GH Pituitary Adenoma: Case Report and Systematic Literature Review

BACKGROUND: Plurihormonal adenomas (PHAs) represent 10%-15% of all functioning pituitary adenomas. The most frequent hormonal associations are with prolactin and growth hormone (GH). Here we describe a rare case of functional adrenocorticotropic hormone (ACTH) and GH microadenoma and report our findings from a systematic literature review of PHA. METHODS: We searched PubMed using the terms plurihormonal pituitary adenoma, ACTH GH pituitary adenoma, and acromegaly AND Cushing's disease. In the 17 articles that were selected for literature review, only 20% (4/20) of patients presented with clinical signs of both diseases. Histologically, 19 were pituitary adenomas composed of two distinct cell populations, while only in 1 case was there evidence of a single cell producing both ACTH and GH. In the case reported here, a 60-year-old woman was incidentally diagnosed with a pituitary microadenoma. Endocrine assessment documented increased levels of insulin-like growth factor 1 and GH; ACTH and cortisol values were within normal ranges. Echocardiography documented ventricular hypertrophy. Because of clinical and biochemical evidence of acromegaly, surgery was recommended. Postoperatively, hormonal replacement therapy was started because of adrenal insufficiency. Her antihypertensive therapy was discontinued due to evidence of normal blood pressure values. Histological examination revealed an ACTH-GH PHA with 2 distinct populations of secreting cells. At 3-year follow-up, the patient showed stable clinical remission and was no longer receiving hormonal replacement therapy. CONCLUSIONS: This is an additional case to the 20 previously reported cases of ACTH-GH PHA. Awareness of this relatively rare entity is clinically relevant. The cytogenesis of ACTH-GH PHA remains a matter of debate, and several hypotheses have been postulated.