SILENT CORTICOTROPH ADENOMA TRANSFORMED IN SECRETING ADENOMA WITH SEVERE CUSHING'S DISEASE AFTER TWO PITUITARY SURGERIES

Introduction. Subtypes of non-functioning pituitary adenomas which may differentiate into functioning adenomas are silent corticotroph adenomas (SCA). These are pituitary tumors positive on immunohistochemical staining for ACTH, but without clinical evidence of Cushing's disease. ase report. FG, a 50 years old man was twice operated for compressive non secreting pituitary macroadenoma (NFPA). After the first surgery he developed hypopituitarism and needed replacement therapy for all the hormonal lines. After the second surgery he rapidly developed the clinical features of Cushing's syndrome. Hormonal dosages showed: the absence of the circadian rhythm of cortisol, high ACTH level and the lack of suppression at 1 mg overnight and high dose Dexamethasone suppression tests. The immunohistochemistry of the previously resected pieces confirmed. the diagnosis of a silent corticotroph adenoma. The patient was referred for conventional antitumoral radiotherapy associated with Cabergoline, then with Ketoconazole treatment. As the high levels of cortisol recurred, he was subjected to bilateral adrenalectomy. Conclusions. We present the rare case of a silent corticotroph macroadenoma which became hypersecreting after two pituitary adenomectomies. SCA may represent another entity in the spectrum of Cushing's syndrome that must be evoked in the cases of pituitary macroadenomas thought to be non-functional.