Endocrine Abstracts

Introduction: Adrenal scintigraphy using [¹³¹I]6ß-iodomethyl-19-norcholesterol has been available since 1975, primarily for the diagnosis of hyperaldosteronism helping to distinguish between unilateral adenoma and bilateral hyperplasia. First line treatment of ACTH-independent form of Cushing syndrome is surgery after localization of the cortisol-producing adrenal tumour.

Case report: A 31-year-old woman has been referred to the endocrine clinic with suspected Cushing syndrome in 2020. Tonsillectomy, lactose intolerance, allergic rhinitis and epilepsy were present in her medical history. She complained of weight gain (30 kg during one year), secondary amenorrhoea, and elevated blood pressure. Physical examination revealed round face, central obesity, oedema on the legs and striae on the skin of the abdomen. Laboratory examinations proved hypercortisolism with suppressed ACTH level. We diagnosed her with hypertension, osteoporosis and impaired glucose tolerance as complications of Cushing syndrome. Adrenal CT showed bilateral adrenal adenomas, with 30 mm diameter in the right side and 17 mm in left side. Iodo-methyl-norcholesterol SPECT/CT proved cortisol-secreting adenoma in the right adrenal gland. Coronavirus pandemic-driven restrictions prevented immediate surgery; this was postponed to an uncertain date in the future. We decided to start metyrapone treatment until surgery, which partially controlled her hypercortisolism. Laparoscopic adrenalectomy in the right side was performed one year later. Histology confirmed cortisol secreting adenoma. After operation, the patient had transient adrenal insufficiency for a few weeks, then normal cortisol levels resumed spontaneously as expected. Clinical features of Cushing syndrome gradually disappeared, her body weight decreased from 126 kg to 78 kg.

Conclusions: In Cushing syndrome with bilateral adrenal lesions, it may be challenging to lateralize the hormone source. Iodo-methyl norcholesterol SPECT/CT is a feasible non-invasive method to localize the cortisol-secreting adrenal adenoma preoperatively.