Endocrine Abstracts

Background: Only a few cases of pituitary tumor swift from non-functioning to Cushing disease (CD) have been previously presented in the literature. The exact mechanism is still unknown. We present a case of a patient with a non-functioning pituitary adenoma, who developed CD from the residual tumor, 13 years after the initial diagnosis and following 2 surgical interventions and radiation therapy.

Case presentation: A 51-year-old woman initially presented with amenorrhea and galactorrhea. The clinical examination showed bitemporal hemianopsia. Laboratory tests: PRL=49.52 ng/ml; FSH=0.76 U/l; LH=0.17 U/l. The CT scan showed a large 2.68 cm (tr) × 3.98 cm (cc) pituitary mass, extending towards the suprasellar compartment, with compression of the optic chiasm. The patient underwent 2 surgical interventions: transfrontal (2005) and transsphenoidal (2006). 4 years later she received radiation therapy (50 Gy). Almost 13 years later (2018), the patient developed mild cushingoid features and the residual pituitary mass developed into an ACTH-secreting adenoma: elevated ACTH level (79.63 pg/ml), loss of circadian rhythm of plasma cortisol with negative result to 1 mg overnight dexamethasone suppression test (9.06 μg/dl). The patient underwent a third transsphenoidal surgery. At the one month follow-up she had normal values of ACTH and plasma cortisol, positive results to 2×2 mg dexamethasone suppression test and a small tumor remnant of 1.3 cm (post-surgical MRI scan).

Conclusions: This case report emphasizes the importance of long term follow-up of each patient for tumor regrowth but also from the hormonal point of view - for pituitary deficiency but mainly cortisol level.