Light at the End of the Tunnel - Abstract

The patient underwent mini-craniotomy and brain biopsy. Intraoperative findings included diffuse leptomeningeal thickening, atrophic optic nerves and a thickened hyperemic pituitary stalk which was biopsied. Histology showed germinoma (CD117+, OCT3/4+). Pre-operative hormonal profile revealed hypopituitarism and he was also diagnosed with central diabetes insipidus. MRI whole spine did not show germinoma involvement. Ultrasound of scrotum was normal. CT scan of thorax, abdomen and pelvis showed no evidence of malignant lesion. He referred to oncology and planned for radiotherapy (CSI 24Gy/16fr + boost 21Gy/14fr), which is due to start shortly. CNS germ cell tumors (GCT) are classified as germinomas or non-germinoma germ cell tumors. Most patients are diagnosed between the age of 10-21, with a male predominance. The most common presentation of CNS GCT are diabetes insipidus, hypopituitarism and visual field defect. These tumors sometimes secrete AFP and b-HCG and finding elevated levels of these tumor marks may aide diagnosis. On MRI, germinomas are isointense or slightly hypointense on T1-weighted images, and isointense or hyperintense on T2-weighted images, and they enhance with gadolinium. They usually appear as midline mass lesions, most commonly near the pineal gland, and less frequently in the suprasellar region, basal ganglia and thalamus. Diffuse involvement is unusual, and to the best of our knowledge, there has only been one other reported case of germinoma mimicking multiple sclerosis and that case did not present with visual symptoms. Radiotherapy is the first line treatment for germinomas and the 2-year survival is better than 90% with radiotherapy alone More recently, systemic chemotherapy with reduced doses of radiation has been advocated as alternative treatment, however longer-term follow-up is required to determine if it will replace standard radiotherapy.