MET-3 A Case of Intrapituitary Adenoma Metastasis from Advanced gastric cancer

Metastasis from extracranial tumor into a pituitary adenoma is a rare case. We report a case of metastasis from gastric cancer to a giant pituitary tumor. A 65-year-old man had been drinking more water and had an increased frequency of urine in 10 years. From that time, the patient was gradually aware of the pain in his left eye. In 20XX the patient had a sudden severe headache and pain of his eyes and visited an ophthalmologist. The patient was referred to our institution with general malaise and nausea, vomiting. A cerebral MRI disclosed Extensive neoplastic lesions from the base of the skull to the nasal cavity. The left eye had esotropia and abduction disorder. Laboratory test demonstrated hyponatremia (Na 126mEq/L) and decreased in plasma osmolality (273mOsm/kg), D-dimer, fibrinogen and CA19-9 were high level. One week after admission, the patient’s symptom was getting worse. The patient underwent FDG PET/CT, which showed FDG avid in the gastric wall and clivus tumor. The lesion was suspected gastric cancer and performed Esophagogastroduodenoscopy. The biopsy-based pathology was showed cubic and round cells with high NC ratio and signet-ring cells containing mucin. And clivus tumor was biopsied at an otolaryngologist because part of the tumor was exposed from the nasal cavity. The biopsy-based pathology was showed a small amount of adenocarcinoma cells which is surrounded by pituitary adenoma. The patient was diagnosed as intrapituitary adenoma metastasis from advanced gastric cancer and has been started radiation therapy. But the level of consciousness dropped sharply, so radiation therapy had become difficult to continue. The patient transferred to palliative care ward and died 3 months after his first visit. In this case, diagnosis and treatment were difficult due to the that the image was a finding a malignant tumor and the rapid progression of symptoms.