Usefulness of gallium-67 scintigraphy in neurohypophyseal germinoma

The application of gallium-67 (67Ga) citrate has not been reported for the detection of an intracranial germinoma. The purpose of this report is to further evaluate the effectiveness of 67Ga scintigraphy in neurohypophyseal germinomas. 67Ga studies in five male patients with histologically verified intracranial pure germinomas were evaluated. Two germinomas were located in the neurohypophysis, two in the pineal region, and one in both the neurohypophysis and pineal region. The control group included 36 patients with histologically verified pituitary macro-adenomas. 67Ga study at the time of original diagnosis showed an abnormal accumulation in two neurohypophyseal germinomas, and negative accumulation in the other germinomas. In the two patients with neurohypophyseal germinomas, 67Ga study showed an abnormal accumulation in the intracranial tumour region in accordance with magnetic resonance (MR) findings. After postoperative irradiation or chemoradiotherapy, MR imaging and 67Ga studies revealed the complete disappearance of this tumour and no metastatic spread. In one of these two patients, a whole-body 67Ga study demonstrated multiple bone metastases one year later, and the reduction of these metastatic regions after chemotherapy. 67Ga study disclosed negative accumulation in all 36 pituitary macroadenomas. Although 67Ga uptake by neurohypophyseal germinomas may not be specific for this condition, this approach may provide some clues for diagnosing patients with neurohypophyseal germinomas.