Progressive Neurosarcoidosis Presenting as Idiopathic Hypopituitarism With Atypical Radiological Features for 13 Years.

Sarcoidosis is an immune-mediated multisystem condition of unknown etiology, characterized by non-caseating granulomatous inflammation. While it commonly affects the lungs and the reticuloendothelial system, it can affect any organ. Most of such cases involve the central nervous system, but the condition rarely presents with symptoms related to hypothalamic-pituitary dysfunction. Neurosarcoidosis primarily targets the leptomeninges, leading to infiltration of the hypothalamus and pituitary gland by granuloma with deficiencies in luteinizing hormone (LH), follicle-stimulating hormone (FSH), and growth hormone (GH) being common. Most patients suffering from sarcoidosis develop neurological manifestations within two years of diagnosis and can present with inflammation in the pituitary gland which can mimic infiltrative pituitary lesions.  We present a 54-year-old male patient, who initially presented with infertility, hypothyroidism, and growth hormone deficiency due to presumed idiopathic hypopituitarism. He had two children following gonadotropin therapy and was maintained on pituitary hormone replacement. After 13 years, he developed further symptoms of neurosarcoidosis including cerebellar infarction, optic neuritis, and paralysis in lower limbs and later developed systemic sarcoidosis including erythema nodosum and cervical lymphadenopathy. Initially, his MRI of the brain showed a decrease in the size of the pituitary gland in 2004, and there were no other features to suggest a systemic illness. A repeat MRI of the brain in 2019 showed an empty sella. His chest X-ray was normal, T-SPOT.TB was negative, and serum angiotensin-converting enzyme (ACE) was undetectable, but eventually, a lymph node biopsy confirmed features of sarcoidosis. Unfortunately, his condition has progressed despite high-dose steroid therapy and methotrexate. This case emphasizes the need for a thorough re-examination of features of neurosarcoidosis in cases of apparently idiopathic panhypopituitarism, to identify patients developing further complications, even after many years. Obtaining a tissue diagnosis is often difficult, and systemic features may be absent. Prospective studies are needed to establish a more uniform strategy for managing hypothalamic-pituitary neurosarcoidosis and identifying factors that predict treatment outcomes.