Mature teratoma of the cisterna magna in an adult patient.

Background: Teratomas are a rare subgroup of CNS germ cell tumors and are histologically classified into mature teratomas, immature teratomas, and teratomas with malignant transformation. CNS teratomas are infrequently found in the posterior fossa and pure mature teratomas of posterior fossa are rare especially in adults. We present a case of a young adult female with a mature teratoma in the cisterna magna.

Case Description: A 26-year-old female presented to the neurosurgery clinic with headache, nausea and vomiting for the past 1 year. She was found to have dysdiadochokinesia on neurological examination. Brain magnetic resonance imaging scan showed a-well defined lesion, hyperintense on T1 and hypointense on T2-weighted sequences located within the cisterna magna. She underwent a suboccipital craniotomy with resection of lesion. Histopathology confirmed the diagnosis of mature cystic teratoma.

Conclusion: Mature teratomas located in the posterior fossa among adults are rare in the literature. We report the second case of mature teratoma in the cisterna magna of an adult patient.