8356 Total Hypophysectomy in Cushing’s Disease: Results from a Terciary Center

Abstract Disclosure: M.V. Lopes: None. M.D. Severino: None. J. Rocha: None. C.R. Peixe: None. M.I. Alexandre: None. A. Gomes: None. M.J. Bugalho: None. Introduction: Transsphenoidal surgery (TSS) is the first line treatment for Cushing’s disease (CD), leading to remission in 70-80% of cases. Though selective adenomectomy is the preferred approach, total hypophysectomy may be needed. Objective: To describe 3 CD patients in which total hypophysectomy was performed. Clinical cases 1. A 58-year-old man with a history of type 2 diabetes (T2D) and obesity, was referred to the Endocrinology Clinic due to abdominal purple striae and facial plethora. Laboratory tests suggested ACTH dependent hypercortisolism, with normal serum ACTH, high 24h urinary cortisol and no cortisol suppression in the overnight 1mg dexamethasone suppression test (DST). The CRH test was suggestive of CD but no adenoma was found on pituitary MRI. Inferior petrosal sinus sampling (IPSS) was compatible with CD with right-sided lateralization. Right hypophysectomy was performed but no CD remission was achieved, so the patient underwent total hypophysectomy. Corticotroph hyperplasia was identified in histology. After 9 months of follow-up, he mantains CD remission. 2.A 37-year-old woman was diagnosed with ACTH dependent hypercortisolism after referral to the Endocrinology Clinic for alopecia, amenorrhea, hypertension and hirsutism. Laboratory tests showed severe hypokalemia, high plasma ACTH and 24h urinary cortisol and the MRI showed a right-sided macroadenoma. Nonetheless, considering the clinical severity, an IPSS was performed and definitely excluded an ectopic Cushing’s syndrome (CS) thus confirming the diagnosis of CD with right-sided lateralization. The patient underwent selective TSS, however, for lack of CD remission, total hypophysectomy was performed. Histology revealed an adenocorticotrophic adenoma. Yet, a year later, she maintains persistence of CD, although less severe, and is under treatment with metyrapone. 3.A 58-year-old woman with a history of T2D and class 3 obesity, was evaluated in our Endocrinology Clinic due to obesity. Her physical examination suggested CS, so this hypothesis was investigated. Laboratory tests suggested ACTH dependent hypercortisolism, with normal serum ACTH, elevated 24h urinary cortisol and no cortisol suppression in the overnight 1mg DST. The high dose DST was suggestive of CD but the pituitary MRI didn’t show an adenoma. IPSS was compatible with CD but it was not possible to determine lateralization. So, total hypophysectomy was performed. An adenocorticotrophic adenoma was identified in histology. Postoperative CD remission was achieved and persists 3 months later. Conclusions: These 3 cases highlight the challenge of treating CD and suggest that in certain cases total hypophysectomy may be the treatment of choice to cure or at least improve CD. Although it is associated with more complications than selective TSS, our patients had no complications, only developed panhypopituitarism and diabetes insipidus. Presentation: 6/1/2024