Visual Vignette

Abstract

Case presentation: A 38-year-old male was admitted with a 4-year history of paroxysmal headache, erectile dysfunction, and fatigue. He also reported dizziness, generalized muscle aches, and weakness. On physical examination, the patient was afebrile. His heart rate and blood pressure were 95 beats per minute and 90/50 mm Hg. respectively. The sodium level was 171 mmol/L, potassium level 3.5 mmol/L, chloride level 135 mmol/L, plasma osmotic pressure 339 mOsm/kgH2O, and urine osmotic pressure 362 mOsm/kgH2O. A pituitary function assessment revealed secondary hypocortisolism and hypogonadotropic hypogonadism. A visual field examination showed no significant abnormalities. Pituitary magnetic resonance imaging (MRI) revealed a large mass in the hypothalamic area and right posterior horn of lateral ventricle with thickening of the pituitary stalk, which was about 6 mm (Fig. 1). Whole-body positron emission tomography-computed tomography using 18F-fluorodexoyglucose showed mild lymph node uptake (Fig. 2 involving the neck, mediastinum, right armpit, supratrochlear area, and groin bilaterally). His erythrocyte sedimentation rate and high-sensitivity C-reactive protein and serum angiotensin-converting enzyme (sACE) levels were in normal ranges. Left inguinal lymph node biopsy revealed epithelioid granulomas. What is the diagnosis?