Synchronous Temporal IDH-Mutant Diffuse Astrocytoma and Posterior Fossa Adult Medulloblastoma: An Extremely Rare Co-existence

Synchronous different primary brain tumors are rare in literature. The presence of supra- and infratentorial tumors at the same time makes constructing the ideal management plan for the affected patient complex. Here, we report the first known case of a patient with simultaneous temporal IDH-mutant diffuse astrocytoma WHO grade II and a posterior fossa medulloblastoma WHO grade IV. This is a 30-year-old female patient presenting with a 2-month history of progressive headache and two attacks of generalized tonic–clonic seizures. MRI brain revealed a large left temporal mass compressing the brainstem and a synchronous posterior fossa tumor. The left temporal lesion was resected, the infratentorial lesion was biopsied, and the patient was discharged for eventual excision of the infratentorial mass. After confirmation of the pathology, the multidisciplinary neuro-oncology team decided to excise the posterior fossa mass; however, 2 weeks later, she presented with acute hydrocephalus, and a ventriculoperitoneal shunt was placed; then, the patient was planned for excision of posterior fossa mass after recovery from the second surgery; unfortunately, 5 days later while waiting for excision, she developed a drop in conscious level, and massive enlargement of the mass was detected in brain imaging with upward herniation; emergent surgical excision was done, and the patient passed away 5 days later. Synchronous different primary brain tumors are rare in literature. Biopsy from multiple synchronous tumors is an important pillar guiding the complex decision, and staged surgical resection of synchronous brain tumors in different locations is usually the best strategy without delay between surgeries whenever the clinical status of the patient allows.