Endocrine Abstracts

Silent corticotropinomas (SCAs) are a subtype of non-functioning pituitary adenomas (NFPAs) demonstrating positive immunoreactivity for ACTH, but without clinical or biochemical features of hypercortisolism. SCAs typically present as macroadenomas with symptoms related to a local mass effect. In some cases SCAs can transform into hormonal active formations with gradually developing symptoms of hypercortisolism.

The aim: To describe a patient with NFPA who over time developed a biochemical only presence of hypercortisolism.

A case description: A young woman presented at the age of 25 years with headaches and oligomenorrhea. The hormonal tests showed the moderate hyperprolactinemia 28.5 ng/ml (n<19.5) with the absence of macroprolactin, normal levels of TSH, IGF1, ACTH, cortisol, LH, FSH, the MRI revealed pituitary macroadenoma 1×1.2 cm with the trend toward suprasellar extension. Short-term medical treatment with low doses of dopamine agonists resulted in drop of prolactin levels below reference values and normalization of menstrual function, which was consistent with the diagnosis of NFPA with hyperprolactinemia due to local mass effect. At the next follow-up 2 years later the patient complained of headaches, weakness and psycho-emotional instability. Lab data revealed high levels of ACTH/cortisol, absence of cortisol suppression at the 1 mg dexamethasone test, and a significant suppression at 8 mg dexamethasone test. The MRI-scan didn’t detect any growth of the adenoma. Remarkably, the patient did not have any clinical features of hypercortisolism (BMI 20.5 kg/m², normal fat distribution, absence of striae and hyperpigmentation, normal levels of blood pressure and blood sugar levels, osteopenia, but no osteoporosis or fractures). At age of 28 years the patient underwent a transnasal adenomectomy with developing of adrenal insufficiency on the second day after operation. The immunohistochemical analysis showed ACTH-immunopositivity which confirmed corticotropinoma, low expression of GH and was negative for prolactin and CRH.

Conclusions: This case demonstrates the gradual development of subclinical Cushing’s disease from NFPA during a period of 3 years. The current diagnosis NFPAs should be made with a high degree of caution and repeated assessment of potential hormonal activity of adenoma to ensure timely treatment.