MON-072 - Tolosa-Hunt Syndrome Mimicking an Aggressive Pituitary Macroadenoma with Panhypopituitarism

Introduction:
The majority of pituitary macroadenomas cause focal visual impairment and hormonal dysfunction that evolve insidiously over months to years. In contrast, rapid onset ophthalmoplegia and hypopituitarism suggest a more aggressive etiology. Tolosa-Hunt syndrome (THS) is a rare, idiopathic granulomatous inflammatory disorder of cavernous sinus, classically presenting with painful ophthalmoplegia. Pituitary involvement is rare. We present an unusual case of suspected THS presenting as an aggressive pituitary mass, with cavernous sinus invasion and panhypopituitarism.

Case Presentation:
A 73-year-old woman with a history of cerebrovascular accident and COPD on home oxygen, presented with headache, generalized weakness, and vomiting, accompanied by fatigue, weight gain, constipation, and edema. Initial laboratory evaluation revealed central hypothyroidism, central adrenal insufficiency, and hypogonadotropic hypogonadism. Pituitary MRI showed a 1.4-cm homogeneously enhancing sellar mass with suprasellar extension and cavernous sinus involvement. She was started on hydrocortisone and levothyroxine.
One month later, she re-presented with worsening headache, diplopia, and left facial paresthesia. Neurologic examination revealed complete left ptosis and decreased sensation in the V1–V3 distribution of the trigeminal nerve. Repeat MRI demonstrated interval progression, including pituitary stalk thickening, abutment of the optic chiasm, left cavernous sinus invasion, and extension into the superior orbital fissure, left Meckel's cave, and along the trigeminal nerve. Extensive serum and CSF evaluation for autoimmune, infectious, infiltrative, and malignant etiologies was unrevealing. CT of the chest, abdomen, and pelvis showed no evidence of malignancy or pulmonary sarcoidosis.
She was empirically treated with high-dose steroids, resulting in rapid radiographic improvement. Based on steroid responsiveness, the pattern of cranial neuropathies, and imaging features, a diagnosis of Tolosa-Hunt syndrome was made. Serial MRIs over six months showed near-complete resolution of cavernous sinus and parasellar lesions, with normalization of pituitary morphology. Clinically, she experienced marked improvement in headache, ptosis, and facial paresthesia. She is currently on a maintenance dose of prednisone and Levothyroxine without reemergence of the disease.


Conclusion:
This case highlights Tolosa-Hunt syndrome as a rare but important mimicker of the pituitary adenoma. Although uncommon, pituitary and stalk involvement with hypopituitarism can occur. Rapid clinical and radiographic progression, cavernous sinus invasion, cranial nerve deficits, and marked steroid responsiveness should prompt consideration of an inflammatory etiology when evaluating aggressive appearing sellar and parasellar masses.

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