This is a biopsy-proven case of hypothalamic amyloidoma. Differential considerations for this appearance would include a granulomatous process such as neurosarcoidosis, infection or an atypical appearance of CNS lymphoma. 

Amyloid deposition within the brain can take many forms, including cerebral amyloid angiopathy, senile plaques of Alzheimer dementia, deposits seen in the encephalopathy of Kuru and of Creutzfeldt-Jacob disease, or tumor-like focal deposits known as amyloidomas. The latter is the most rare form of cerebral amylodosis, with only a small number of case reports in the literature.