Steroid-resistant Tolosa–Hunt syndrome with a de novo intracavernous aneurysm: A case report

BACKGROUND: We report a case of steroid-resistant Tolosa–Hunt syndrome (THS) with recurrent bilateral painful ophthalmoplegia, accompanied with sphenoid sinusitis, pituitary abscess, and an aneurysm arising from the cavernous portion of the internal carotid artery. CASE DESCRIPTION: A 53-year-old woman suffered severe left painful ophthalmoplegia. A magnetic resonance image (MRI) revealed thickness of the left cavernous sinus (CS). Steroid was administrated under the diagnosis of THS, and the symptom transiently diminished. However, painful ophthalmoplegia fluctuated bilaterally after tapering the steroid. An MRI showed development of bilateral cavernous lesions associated with sphenoid sinusitis, pituitary abscess, and an aneurysm in the left C4 segment. Biopsy and drainage of the lesions were performed with an endoscopic transsphenoidal procedure. The histological examination showed nonspecific granulomatous inflammation. The methotrexate (MTX) was effective to reduce the CS and pituitary lesions; however, the aneurysm slightly increased and remained unchanged in size thereafter. CONCLUSIONS: To our knowledge, this is the first report of a growing de novo C4 aneurysm in THS. Surgical intervention and administration of MTX should be attempted in steroid-resistant THS. Careful observation with serial MRI and MR angiography is important to manage the complicated THS.