Papillary Thyroid Cancer With Pituitary Gland Metastasis: A Unique Encounter

The pituitary gland is a rare metastatic site, and thyroid cancer (TC) metastasis to the pituitary gland is immensely uncommon. We report the case of a 45-year-old male in whom pituitary metastasis (PM) discovery during the immediate postoperative period complicated the management of papillary thyroid cancer (PTC). His postoperative magnetic resonance imaging (MRI) of the pituitary lesion showed a progression in size with persistent optic nerve compression. The critical location of the pituitary lesion and the rapid progression dictated the treatment course. The pituitary lesion was non-iodine avid, and thus we opted for external beam radiation therapy (EBRT). He received 1,200 centigray (cGy) with Gamma knife radiosurgery with steroid cover. In our case, the aggressive histological and clinical variant of PTC consisted of multiple metastatic sites involving large volume pulmonary, skeletal, and chest wall lesions coupled with crucial macro metastatic pituitary mass. The patient was offered radioactive iodine to treat other iodine avid metastases in the lungs and bones and was also offered EBRT to target skeletal lesions. Systemic treatment with tyrosine kinase inhibitor was also discussed with the patient. Our case encourages clinicians to exercise vigilance and a high index of suspicion for PM when a patient with any pre-existing cancer presents with visual disturbance, cranial nerve deficit, or symptoms suggestive of hormonal deficiency. It also highlights the importance of involving endocrinologists before performing any surgery on the endocrine organs to ascertain the integrity of the endocrine function of the glands.