Background: The medulla oblongata is the lower half of the brainstem. It contains the cardiac, respiratory, vomiting, and vasomotor centers and deals with autonomic functions such as breathing, heartbeat, and blood pressure. Primary medulla oblongata germinoma is very rare and less than 20 cases have been reported in the English literature.
Case description: A 22-year-old female without any particular past medical history presented to us in October 2012 with the chief complaint of dyspnea and frequent choking for 1 month. Neurological examination revealed lower cranial nerve palsies and nystagmus. Her brain computed tomography (CT) and brain magnetic resonance imaging (MRI) demonstrated a mass lesion at the dorsal surface of medulla oblongata with extension into the inferior fourth ventricle and foramen magnum. She underwent bilateral suboccipital craniotomy and C1 laminoplasty with the grossly total resection of the tumor. The histological examination of the tumor proved germinoma. Postoperative adjuvant radiotherapy was arranged. The latest brain MRI and whole spine MRI done 1 year after surgery showed neither residual nor recurrent tumor in the whole axis. She is regularly followed-up at our outpatient department and is doing well except having left vocal cord palsy, which occurred before surgery.
Conclusion: Medulloblastoma, ependymoma, glioma, hemangioblastoma, and cavernous angioma are common intraaxial tumors in the medulla oblongata and fourth ventricle. Intracranial germ cell tumors originate from extragonadal seminal cells and have been found in 0.4-3.4% of patients with primary central nervous system (CNS) tumors in Western countries, while the incidence is reported to be 5-8 times greater in Japan and the Far East. Although germinoma of medulla oblongata is rare and difficult to diagnose preoperatively, it should be included in the differential diagnosis of medulla masses with fourth ventricle extension, especially in Asian population.
Keywords: Fourth ventricle; germinoma; medulla oblongata.