Pituitary acrogigantism and ectopic Cushing's syndrome

Abstract

A 21-year-old man presented for evaluation of Cushing's syndrome. His medical history was notable for an incidental diagnosis of acrogigantism at the age of 18 years, when he presented for an unrelated illness. At that time, investigations showed hypersecretion of growth hormone (somatotropin), normal serum cortisol, and a 1·6 × 1·8 × 2·0 cm sellar-suprasellar mass without parasellar extension (appendix p 1). He underwent transnasal transsphenoidal resection of the pituitary lesion, after which biochemical remission was reached at the cost of panhypopituitarism, including central diabetes insipidus. Histopathological examination showed a densely granulated somatomammotrophic adenoma with positive immunostaining for growth hormone and prolactin and negative staining for adrenocorticotropic hormone (ACTH). The patient was prescribed replacement therapy with levothyroxine, prednisolone, injectable testosterone ester, and oral desmopressin. Repeat imaging 3 months after surgery showed a partial empty sella and a thin rim of pituitary tissue, suggesting complete resection of the pituitary lesion (appendix p 1). 6 months after surgery, features of hypercortisolism were evident, including prominent weight gain (about 40 kg), extensive broad purple and dehiscent striae, severe proximal myopathy, tinea corporis, and repeated episodes of hypokalaemic periodic paresis. Glucocorticoid replacement was therefore discontinued (6 months before the patient presented to us).