To report the third documented case of trigeminal neuralgia (TN) secondary to a pituitary macroadenoma, highlighting its rarity as an isolated presentation affecting all three branches of the trigeminal nerve. 

Pituitary macroadenomas are often associated with headaches, visual disturbances, and endocrine dysfunction. TN resulting from these adenomas is rare, particularly when affecting multiple divisions of the trigeminal nerve, and often indicates cavernous sinus invasion. TN usually arises from vascular compression of the trigeminal nerve root entry zone, with less common causes including multiple sclerosis and arteriovenous malformations. Surgical resection is the primary treatment for symptomatic adenomas but poses risks for the elderly patients who may be poor surgical candidates. 

A 92-year-old male, diagnosed 3 months prior with a pituitary macroadenoma after presenting with headaches, declined surgical intervention due to being a poor candidate. The patient now presents with a 4-day history of progressive severe left-sided facial pain involving the ophthalmic, maxillary, and mandibular branches of CNV. The pain is so intense that it prevents the patient from opening his mouth, leading to significant dehydration, and it was triggered by light touch and talking. Endocrinological evaluation was unremarkable. MRI findings confirmed a large suprasellar hypo-enhancing mass lesion extending to the cavernous sinus. 

Carbamazepine and Gabapentin were initiated, and the dose up titrated until optimum pain control was achieved. Alternative options were presented including glycerol rhizotomy and sphenopalatine nerve block which were deferred by the patient. The patient's symptoms improved with medical management, with no plans for surgical intervention due to his status as a poor surgical candidate. 

TN secondary to pituitary macroadenoma is a rare condition that poses unique management challenges, particularly in elderly patients who are not suitable for surgery. In such cases, conservative management aimed at pain control and quality of life is essential.