Abstract Introduction Hypothalamo-chiasmatic lesions pose a diagnostic challenge as they can mimic gliomas, hypophysitis, infiltrative or granulomatous disease and histiocytic disease. Endocrine dysfunction often precedes other clinical signs, so early recognition and integration of hormonal, radiologic, and systemic findings is critical. Clinical Case A 56-year-old woman presented with fatigue, generalized weakness, polyuria, and polydipsia. Initial laboratory testing revealed central hypothyroidism with low free T4 (0.43 ng/dL) and inappropriately normal TSH (4.1 µIU/mL). Further endocrine tests confirmed panhypopituitarism: cortisol 1.92 µg/dL, prolactin 99 ng/mL, ACTH 6.8 pg/mL, LH 0.9 mIU/mL, FSH 3.3 mIU/mL, estradiol 5 pg/mL, GH 0.01 ng/mL, and IGF-1 53 ng/mL. The osmolality of the urine was 186 mOsm/kg. A 1 µg short ACTH stimulation test Synacthen showed an inadequate cortisol response (0, 30, 60 min: 2.31, 9.09, 10.2 µg/dL), confirming secondary adrenal insufficiency. A water deprivation test revealed central diabetes insipidus, which responded immediately to desmopressin. Replacement therapy with glucocorticoids, levothyroxine, and desmopressin was initiated. Sellar MRI showed a 14×9 ×11 mm homogeneously enhancing lesion in the hypothalamic chiasm region extending to the pituitary stalk, with a decreased height of the pituitary gland, an empty sella, and loss of the bright spot in the posterior pituitary. Differential diagnoses included a hypothalamic glioma and hypophysitis. A comprehensive immunological and infectiological examination (ANA, ENA, ANCA, RF, anti-CCP, viral serologies) was negative. The tumor markers (β-hCG, AFP) were normal. Serum ACE was slightly elevated (83 IU; reference value 9–67), while IgG4 was normal. Chest radiograph showed bilateral hilar fullness, and HRCT confirmed hilar and interlobar lymphadenopathy (short axis 8.5 mm). PET-CT showed strong FDG uptake in the hypothalamo-chiasmatic lesion and para-aortic and iliac lymph nodes, suggesting systemic granulomatous or histiocytic disease. Endobronchial ultrasound-guided lymph node biopsy at the hilus showed granulomatous lymphadenitis without necrosis, suggestive of sarcoidosis. The hypothalamic lesion was interpreted as neurosarcoidosis. The patient received glucocorticoid and methotrexate therapy. The MRI follow-up examination after six months showed a complete regression of the hypothalamo-chiasmatic lesion. Conclusion This case emphasizes the diagnostic complexity of hypothalamo-chiasmatic lesions associated with panhypopituitarism and central diabetes insipidus. A systematic hormonal, radiologic, and systemic examination in conjunction with tissue diagnosis, allowed accurate identification of neurosarcoidosis and initiated effective targeted therapy, leading to complete radiologic resolution.
Tunç et al. (Thu,) studied this question.