Endocrine Abstracts

Silent corticotroph adenomas are a distinctive subgroup of nonfunctioning pituitary tumours without biochemical or clinical evidence of Cushing’s disease. They are diagnosed after surgery by positive immunostaining for ACTH. They are usually macroadenomas with more aggressive behaviour. On rare occasions, they transform into active Cushing’s disease, with elevated serum ACTH levels. I report a case of a 44 years old lady I first examined in the postoperative neurosurgical unit on the third day following a second transsphenoidal intervention for a pituitary macroadenoma. Two years before (Oct 2020), she was diagnosed with a pituitary macroadenoma symptomatic with a visual field defect. A first transsphenoidal resection was performed with complete recovery of her visual field. The three months control MRI described a tumoral rest (7/6/4 mm). She gained hypopituitarism on the gonadotropic and thyrotropic axis, and replacement therapy was started without requiring hydrocortisone replacement. Immunohistochemistry revealed positive staining for ACTH and Ki67 of 12%. Subsequent MRI shows a gradual increase of the tumoral rest. On February 2022, the patient complained of accelerated vision loss. The MRI shows a sellar tumour with a suprasellar extension of 25/20/27 mm. The hormonal sampling shows high ACTH (x2 UNL) with high normal cortisol. Suppression tests on the corticotrophic axes were not performed, and the patient was addressed for a second surgery. Following the second surgery, she fully recovered her vision and was discharged with hydrocortisone substitution therapy until testing the corticotrophic axis could give reliable results. The immunohistochemistry shows Ki 67 - of 12% and positive p 53 with a nuclear index of 70%. Three months following surgery, her cortisol levels were undetectable while on hydrocortisone substitution treatment with a slowly increasing trend for ACTH to 25 pg/ml (nr 7-63). An MRI showed a suprachiasmatic tumoral rest; the patient was referred for radiotherapy.