A rare presentation of pediatric germinoma mimicking optic pathway glioma: illustrative case.

Background: Intracranial germinomas are rare pediatric tumors classically occurring in the pineal region, the infundibular recess, and septal region. Hypothalamic-optic pathway gliomas are typically pilocytic astrocytomas that can occur at any point along the optic pathway or within the hypothalamus. Germinomas are highly radiosensitive and chemotherapy-sensitive with an overall good prognosis after treatment. In contrast, hypothalamic-optic pathway gliomas are typically managed with observation if asymptomatic and treated with chemotherapy or targeted therapies if they are symptomatic or progressive.

Observations: Suprasellar germinomas are a known alternative location; however, suprasellar germinomas extending along the optic pathway are exceedingly rare. Neurosurgeons, neuroradiologists, and neuro-oncologists should consider germinomas when crafting a differential around a midline suprasellar lesion involving the optic pathway. Given the differences in treatment of a germinoma versus an optic pathway glioma, obtaining sufficient tissue for a diagnosis is paramount in these rare cases with radiographic equipoise.

Lessons: The authors report a case of a suprasellar germinoma mimicking an optic pathway glioma in its radiographic appearance. The intraoperative appearance of the lesion during the attempted transsphenoidal biopsy appeared consistent with an optic pathway glioma. Subsequent biopsy via a pterional approach confirmed the diagnosis of germinoma. https://thejns.org/doi/10.3171/CASE24804.