Commentary “Posterior Cranial Fossa Gangliogliomas”

The authors illustrate an interesting case of a posterior fossa ganglioglioma that presented with over a decade of chronic headaches. An initial CT study performed 10 years prior had failed to reveal the lesion. Ultimately, an MRI study showed a cerebellar mass and direct biopsy secured the diagnosis.

This case is interesting for a variety of reasons. The long duration of symptoms before diagnosis could no doubt have been shortened by early MR imaging, and this raises the possibility that patients with prolonged or severe headache histories should be aggressively imaged. The fact that the headaches improved after subtotal resection and biopsy suggests that surgery may still play a role even for tumors that cannot be fully resected. While I do not typically employ the sitting position for a supracerebellar approach, I agree that this avenue of attack offers the best exposure to the region.

It is notable that the chronic presentation (11 years) more closely followed the expected history of brainstem gangliogliomas rather than similar cerebellar tumors. With its localization at the right cerebellar peduncle with extension toward the tectum and pineal recess, the tumor might also be classified as a brainstem lesion. Without serial studies, it would not be possible to define precisely exactly where it arose.

The article also very succinctly summarizes the known literature for cerebellar gangliogliomas and offers reasonable recommendations regarding adjuvant treatment. Given the generally favorable prognosis, even for brainstem locations, chemotherapy and radiation are reserved for progressive growth or malignancy. The impact of radiosurgical treatment has yet to be defined. No doubt, this patient must have regular follow-up with serial MR imaging to assess for tumor growth and hydrocephalus.