Primary intrinsic optic chiasm germinoma

Primary anterior visual pathway germinoma in a 13-year-old boy: A case report

Background

Primary optic nerve and chiasmal germinomas are very rare. These lesions can commonly be mistaken for optic pathway gliomas based on imaging alone. It is radiosensitive and cured in most of the cases.

Case Description

We report a rare case of a 13-year-old boy with primary bilateral optic nerves and chiasmal germinoma who underwent partial surgical resection followed by radiotherapy. Follow-up brain imaging after two months post-radiotherapy showed interval regression of the tumor. Our literature review identified that 12 reported cases of primary anterior visual pathway germinoma had been reported to regress significantly post-radiotherapy alone or with chemotherapy.

Conclusion

Histologic correlation is essential for appropriate treatment, alleviating symptoms, and avoiding irreversible vision loss.

Involvement of the optic pathway and outcome of visual function in patients with neurohypophyseal germ cell tumor

BACKGROUND

Patients with neurohypophyseal germ cell tumors (GCTs) typically present with visual problems. Hence, this study aimed to assess optic pathway involvement based on clinical and radiological findings and to validate the outcome of visual function.

METHODS

A total of 16 patients with newly diagnosed neurohypophyseal GCTs who were treated at the University of Tsukuba Hospital between 2000 and 2020 were included in this study.

RESULTS

The median interval from symptom onset to diagnosis was 173.5 days (range, 33-1588 days). Patients with visual disturbance at diagnosis had a longer time to diagnosis compared with those without. Ophthalmologic abnormalities were frequently observed, with an incidence rate of 69%. Fifty percent of patients exhibited optic pathway involvement detected via magnetic resonance imaging (MRI). Visual impairment was more severe in the patients with optic pathway involvement (p = 0.002). Post-treatment visual impairment was improved but was still significantly severe in patients with optic pathway involvement than in those without involvement (p = 0.010). Visual field deficit more likely remained with an improvement rate of 50%, whereas the improvement rate of visual acuity was 78%. Further, none developed late-onset visual deterioration during the follow-up period.

CONCLUSIONS

Visual disturbance and optic pathway involvement are common in neurohypophyseal GCTs. Visual impairment particularly in patients with optic pathway involvement on MRI is more likely to remain at follow-up, although the outcome of visual function is acceptable in most cases.

Primary intrinsic chiasmal germinoma

Intracranial germinomas are typically present in the suprasellar or pineal location, and their origin within the optic nerve or chiasm is extremely rare. We report a 25-year-old woman with an exophytic primary optic chiasm germinoma who underwent partial resection followed by radiation and had no detectable tumor on magnetic resonance imaging at 1-year follow-up.

Non-compressive disorders of the chiasm

Chiasmal dysfunction produces a characteristic clinical picture, regardless of the mechanism. In most cases a compressive lesion is the cause. In occasional cases, however, no such extrinsic mass is found and other possible etiologies must be explored. In some of these cases, the pathologic process is identifiable with appropriate neuroimaging. For example, inflammation, infiltrative tumors, and radiation necrosis produce intrinsic chiasmal enhancement. Chiasmal ischemia may require specialized magnetic resonance (MR) sequences for diagnosis. Chiasmal hemorrhage, trauma and chiasmal herniation typically produce distinctive changes on noncontrasted imaging. In cases of metabolic insult, either toxic or hereditary, radiographic changes are typically absent. In each of these, the correct diagnosis can usually be made with a combination of clinical and radiographic features.