Endocrine Abstracts

Introduction: Pituitary metastasis (PM) is a rare condition and associated with a reduced life-span. The most common primary sites are breast and lung, followed by thyroid and renal cell carcinoma. Patients with PM are mostly asymptomatic and incidentally discovered during neuroimaging. Characteristic symptoms are reported in <20% and most commonly include visual involvement, diabetes insipidus, and panhypopituitarism. We here describe a case with malignant melanoma (MM) who presented with acute hypoglycemia.

Case-description: A 60-year female presented with recurrent episodes of fasting hypoglycemia up to 1.6 mmol/l, over a period of two days. She was recently diagnosed with MM of fingernails. Medications included oral estrogen and progesterone. Biochemistry revealed panhypopituitarism: morning cortisol 148 nmol/l, ACTH 2.6 mg/l, FT4 4 pmo/l, TSH 1.1 mU/l, IGF1 3.6 nmol/l, FSH 2.8 IU/l, LH 1.7 IU/l. Serum prolactin was elevated (2324 mIU/mL). She did not have polyuria, optic-chiasmal compression, or ophthalmoplegia. MRI sella revealed a bulky, and heterogenous pituitary gland and pituitary stalk was thickened. 18FDG-PET/CT demonstrated intense avid uptakes in the sellar region, right orbit, liver, adrenal and multiple bones. Thus, the pituitary lesion was regarded as possible metastasis and a biopsy was avoided. She was put on replacement doses of hydrocortisone and levothyroxine, which resulted into an improved glycemic control. She received Dabrafenib and Trametinib for management of MM. Immuno-histochemistry was positive for BRAF-mutation.

Discussion: Only few cases with MM with PM have been described in the literature until today. Our patient developed acute symptomatic hypoglycemia in the context of central adrenal insufficiency, likely related with the new diagnosis of PM. It is further uncommon for adrenal insufficiency to manifest as hypoglycemia in adults. The case highlights considering PM in elderly patients with pituitary mass and evaluation for adrenal insufficiency in patients with hypoglycemia.