Background: Autoimmune hypophysitis very rarely spreads to nearby organs outside the pituitary tissue, for unknown reasons, with only 5 reported cases of hypophysitis spreading over the cavernous sinus.
Case presentation: Three patients presented with cases of non-infectious hypophysitis spreading outside the pituitary tissue over the cavernous sinus. All three cases were diagnosed with histological confirmation by transsphenoidal surgery, and the patients showed remarkable improvement with postoperative pulse dose steroid therapy, including disappearance of abnormal signal intensities in the bilateral hypothalami on magnetic resonance imaging, resolution of severe stenosis of the internal carotid artery, and normalization of swollen pituitary tissues. Two of 3 cases fulfilled the histological criteria of immunoglobulin G4-related disease, although none of the patients had high serum immunoglobulin G4 level.
Conclusion: The true implications of such unusual spreading of hypophysitis to nearby organs are not fully understood, but the mechanism of occurrence might vary according to the timing of inflammation in this unusual mode of spreading. Pulse dose steroid therapy achieved remarkably good outcomes even in the patient with progressive severe stenosis of the internal carotid artery and rapid visual deterioration.