Thyrotoxicosis with absence of clinical features of acromegaly in a TSH- and GH-secreting, invasive pituitary macroadenoma

A 54-year-old woman presented with bi-temporal hemianopia, palpitations, and diaphoresis. An invasive pituitary macroadenoma was discovered. The patient had biochemical evidence of secondary hyperthyroidism and GH excess; however, she did not appear to be acromegalic. Surgical removal of the pituitary mass revealed a plurihormonal TSH/GH co-secreting pituitary adenoma. TSH-secreting adenomas can co-secrete other hormones including GH, prolactin, and gonadotropins; conversely, co-secretion of TSH from a pituitary adenoma in acromegaly is infrequent. LEARNING POINTS: This case highlights an unusual patient with a rare TSH/GH co-secreting pituitary adenoma with absence of the clinical features of acromegaly. Plurihormonality does not always translate into the clinical features of hormonal excess. There appears to be a clinical and immunohistochemical spectrum present in plurihormonal tumors.