Endocrine Abstracts

Introduction: Pituitary adenomas are mostly benign tumors which may be clinically functioning or non-functioning and ACTH secreting tumors make up 15% of them. Up to 20% of corticotroph adenomas which don’t have any biochemical or clinical evidence of hypercortisolism are known as silent corticotroph adenomas.

Case 1: A 54 years old male presented with blurred of vision and headache that increasing in severity within six years. Physical examination and visual field tests were normal. After initial evaluation, the brain MRI was performed and pituitary mass was detected 33x27x28mm diametered, heterogeneous in nature, extented to suprasellar region, infiltrates cavernous sinuses and contact with optic chiasma. Pituitary hormones were in normal range except high serum ACTH level. Twenty four hour urine free cortisol level and dexamethasone supression test are within normal range and physical examination did not show any cushingoid signs. Transnasal transsphenoidal surgery was performed and pathology reported as “densly granulated corticotroph adenoma, Ki 67: %3, p53 (-)”.

Case 2: A 55 years old male admitted to hospital with a complaint of headache. Past medical history includes prior pituitary surgery, depression and hypertension. His arterial tension and neurologic examination was normal. Prior pituitary pathology report could not be reached. After first evaluation he underwent to brain MRI that revealed pituitary adenoma about 12x10x5mm in diametered, no sign for extension to optic chiasma and cavernous sinuses. Pituitary hormones were in normal range except high serum ACTH level. Twenty four hour urine free cortisol level and dexamethasone supression tests were in normal range, patient had also no cushingoid signs. Transnasal transspheonidal surgery was performed and pathologic examination revealed “corticotroph staining adenoma as Ki 67: %2 and p53 (-)”.

Discussion: Cushing’s disease are detected in 0.7 to 2.4 per million individuals per year. Most of the corticotroph adenomas are microadenomas. Silent ACTHomas are generally >1 cm in diameter. It is difficult to differentiate pre-perioperatively. Most of silent adenomas don’t exhibit any hormonal and physical abnormalities except for serum ACTH level. But serum ACTH level is not enough alone to diagnose Cushing’s disease. It is thought that high-measured ACTH is immunologically active but biochemically inactive. So clinicians must be avoided to make wrong diagnosis. Clinicians also should keep in mind that sometimes silent adenomas cause subclinical Cushing diseases during progression of disease and most of them are difficult to remove surgically because of extension to surrounding tissue.