P-47 Rare case of acromegaly due to plurihormonal pituitary adenoma and ACTH-independent Cushing syndrome

Abstract

Abstract Introduction The concurrence of acromegaly and Cushing syndrome is infrequent. Pituitary adenomas are responsible for acromegaly and for Cushing syndrome in about 95% and 80% of cases respectively. Except adrenal adenoma, the other causes of Cushing syndrome remain rare. We here describe a case of a Tunisian patient with acromegaly due to plurihormonal pituitary adenoma and ACTH-independent Cushing syndrome with bilateral macronodules. Clinical Case A 35-year-old male patient was diagnosed with acromegaly by acrofacial dysmorphia. He had a family history of type 2 diabetes mellitus and hypertension but no endocrine diseases. He has diabetes mellitus for 15 years, hypertension and obstructive sleep apnea. Physical examination showed multiple blue nevi in the trunk. IGF-1 was elevated (1680ng/mL) and GH levels were not suppressed after an oral glucose load (nadir 78ng/mL). He had hypogonadotropic hypogonadism with normal prolactin (9,66ng/mL). Basal cortisol, FT4 and TSH levels were in the normal ranges. Pituitary MRI showed pituitary macroadenoma of 25×20.7 mm, invading both cavernous sinuses and compression of optic chiasma. He underwent transsphenoidal resection with histology confirming a prolactin, GH and LH co-secretory pituitary adenoma. He received postoperatively somatostatin analogue and cabergoline, in addition to external radiotherapy. Ultrasonography found infracentimetric EU-TIRADS 2 left nodule and multiple colloid cysts of the thyroid, testicles microlithiasis and no cardiac myxomas. Nine years after the diagnosis of acromegaly, bilateral adrenal adenomas (left:14 mm, right: 9 mm) were incidentally discovered by CT-scan done for abdominal pain. Low dose dexamethasone suppression test was carried out showing no suppression of cortisol and the low ACTH level confirmed ACTH-independent Cushing syndrome. Conclusion In our patient, at least two endocrine syndromes deserve to be mentioned. The first syndrome is Multiple Endocrine Neoplasia Type 1 but calcium and PTH levels were normal and there was no sign for neuroendocrine tumors. The second one is Carney's complex since our patient has acromegaly and multiple blue nevi which are two major criteria confirming the diagnosis. Cushing syndrome in Carney's complex is related to primary pigmented nodular adrenal disease characterized by micronodular hyperplasia. However, bilateral macronodules could be found in up to 30% of cases.