Regression of pituitary macroadenoma after endovascular embolization of thoracic cerebrospinal fluid-venous fistula for symptomatic intracranial hypotension: Illustrative case

Background: Pituitary hyperemia and gland enlargement can be cardinal features of intracranial hypotension secondary to cavernous sinus and epidural venous plexus distention. This phenomenon can therefore complicate radiographic interpretation of sellar lesions when both diagnoses co-exist. We report a unique case of a rapidly enlarging pituitary macroadenoma in the setting of a thoracic cerebrospinal fluid (CSF)-venous fistula causing symptomatic intracranial hypotension. Case Description: A 53-year-old female with no prior neurosurgical history presented with recurrent orthostatic headache. Magnetic resolution imaging revealed a pituitary lesion along with pathopneumonic signs of intracranial hypotension. The tumor grew rapidly on surveillance imaging, prompting consideration of surgery. Further work-up, however, revealed a thoracic CSF-venous fistula. Endovascular embolization of the fistula led to near-complete resolution of her symptoms and durable radiographic tumor regression. Conclusion: Pituitary macroadenomas are susceptible to local hemodynamic changes occurring as a sequelae of occult CSF leak. Identification and treatment of the underlying etiology were sufficient to induce tumor regression.