Hypothalamitis: a diagnostic and therapeutic challenge.

To report an unusual case of biopsy-proven autoimmune hypophysitis with predominant hypothalamic involvement associated with empty sella, panhypopituitarism, visual disturbances and antipituitary antibodies positivity. We present the history, physical findings, hormonal assay results, imaging, surgical findings and pathology at presentation, together with a 2-year follow-up. A literature review on the hypothalamic involvement of autoimmune hypophysitis with empty sella was performed. A 48-year-old woman presented with polyuria, polydipsia, asthenia, diarrhea and vomiting. The magnetic resonance imaging (MRI) revealed a clear suprasellar (hypothalamic) mass, while the pituitary gland appeared atrophic. Hormonal testing showed panhypopituitarism and hyperprolactinemia; visual field examination was normal. Pituitary serum antibodies were positive. Two months later an MRI documented a mild increase of the lesion. The patient underwent biopsy of the lesion via a transsphenoidal approach. Histological diagnosis was lymphocytic "hypothalamitis". Despite 6 months of corticosteroid therapy, the patient developed bitemporal hemianopia and blurred vision, without radiological evidence of chiasm compression, suggesting autoimmune optic neuritis with uveitis. Immunosuppressive treatment with azathioprine was then instituted. Two months later, an MRI documented a striking reduction of the hypothalamic lesion and visual field examination showed a significant improvement. The lesion is stable at the 2-year follow-up. For the first time we demonstrated that "hypothalamitis" might be the possible evolution of an autoimmune hypophysitis, resulting in pituitary atrophy, secondary empty sella and panhypopituitarism. Although steroid treatment is advisable as a first line therapy, immunosuppressive therapy with azathioprine might be necessary to achieve disease control.