Intracranial mixed germ cell tumor mimicking a meningioma: illustrative case.

BACKGROUND

Germ cell tumors have a low incidence in the Hispanic population and most frequently present in pineal or suprasellar regions. Only a few cases have been reported with an initial image compatible with a meningioma-like appearance.

OBSERVATIONS: A 24-year-old male with photopsias, headache, and left homonymous hemianopia presented with a right parieto-occipital extra-axial mass. MRI revealed a heterogeneous enhancing mass, with hemorrhagic zones and surrounding vasogenic edema. Surgery with a near-total resection was performed and an extra-axial lesion with infiltration of the deep venous system was found. Histopathological evaluation revealed a mixed germ cell tumor with a yolk sac tumor and immature teratoma. Postoperative investigation revealed elevated serum α-fetoprotein and pulmonary metastasis. Radiotherapy and chemotherapy followed surgical treatment.

LESSONS: Germ cell tumors can present as extra-axial dura-based lesions and should be suspected in young patients with imaging showing lesions with cystic or hemorrhagic components. Pulmonary metastases are infrequent but may be present. For successful treatment, chemotherapy and radiation therapy should always be considered. https://thejns.org/doi/10.3171/CASE25855.