Growth hormone-releasing hormone-secreting giant pheochromocytoma causing acromegaly: a case report with a review of the literature.

The ectopic secretion of growth hormone (GH) or growth hormone-releasing hormone (GHRH) is responsible for fewer than 1% of acromegaly cases. Furthermore, within this small population, GHRH-secreting pheochromocytomas/paragangliomas (PPGLs) are even rarer. A 57-year-old Japanese woman presented to our hospital for treatment of a large left-sided pheochromocytoma (PCC). A physical examination revealed enlargement of the nose and lips as well as macroglossia, thereby raising the suspicion of acromegaly, which was biochemically confirmed by a 75-g oral glucose tolerance test. Magnetic resonance imaging demonstrated a slightly enlarged pituitary gland but no definitive tumor. A left adrenalectomy was performed after careful dose titration of doxazosin and metyrosine. Postoperative biochemical improvement of GH excess and immunohistochemical analysis of the resected tumor confirmed the diagnosis of GHRH-secreting PCC. Given the possibility that PPGLs produce various ectopic hormones and peptides, thorough physical examinations remain fundamental for the accurate diagnosis and optimal management of patients with these tumors.