Primary midbrain cystic germinoma mimicking glioma: a case with neuroendoscopic biopsy

Primary midbrain germinomas: Report of a rare case with an updated review of the literature

Intracranial germinomas are most commonly extra-axial germ cell tumors that are predominantly found in the pineal and suprasellar regions. Primary intra-axial midbrain germinomas are extremely rare, with only eight reported cases. Here we present a 30-year-old man who presented with severe neurological deficits, with an MRI that showed a heterogeneously enhancing mass with ill-defined margins in the midbrain, and with surrounding vasogenic edema extending to the thalamus. The presumptive preoperative differential diagnosis included glial tumors and lymphoma. The patient underwent a right paramedian suboccipital craniotomy and biopsy obtained through the supracerebellar infratentorial transcollicular approach. The histopathological diagnosis was reported as pure germinoma. After patient discharge, he received chemotherapy with carboplatin and etoposide, followed by radiotherapy. Follow-up MRI at up to 26 months showed no contrast-enhancing lesions but a mild T2 FLAIR hyperintensity adjacent to the resection cavity. Differential diagnosis of midbrain lesions can be challenging and should include glial tumors, primary central nervous system lymphoma, germ cell tumors, and metastasis. Accurate diagnosis requires adequate tissue sampling. In this report, we present a very rare case of a primary intra-axial germinoma of the midbrain which is biopsied via a transcollicular approach. This report is also unique as it provides the first surgical video of an open biopsy and the microscopic appearance of an intra-axial primary midbrain germinoma via a transcollicular approach.

Primary midbrain germinoma relapse-free for 5 years: A case report

Background

The biology and clinical course of intracranial germinomas differ as per their location of occurrence. Germinoma of the primary midbrain is particularly rare, and its clinical features, treatment strategies, and long-term prognosis remain uncertain.

Case Description

A 39-year-old man who had been diagnosed with midbrain germinoma by open biopsy through the occipital transtentorial approach had undergone chemoradiotherapy and achieved 5 years with no recurrence.

Conclusion

Germinomas should be considered as a differential diagnosis for adolescents and young adult men with mesencephalic tumors, and reliable sampling followed by chemoradiotherapy must be performed.

Primary Germinoma Originating from the Insular Lobe: A Case Report and Review of the Literature

BACKGROUND

Primary intracranial germinomas occurring in the cerebral hemisphere are extremely rare, with only a few reported cases in the literature. We describe an unusual case of a primary germinoma that developed in the insular lobe, with little involvement in the basal frontal lobe.

CASE DESCRIPTION

A 19-year-old man presented with headache and vomiting. Magnetic resonance imaging showed a solitary, ring-like enhanced lesion in the left hemisphere, and a preliminary diagnosis of glioma was made. Surgery was performed, and the diagnosis of germinoma was made based on the histopathologic results.

CONCLUSIONS

The causes of ectopic germinomas of the midline structures of the brain are still unclear, but the theory of misplacement may partially clarify this phenomenon. Reflecting a lack of definitive management guidelines for atypical germinoma, the present patient was treated with focal radiotherapy around the lesion after surgery and achieved remission by 34 months postoperatively.

Mixed germ cell tumor of the midbrain. Case Report

This 14-year-old boy presented with left hemiparesis, gait disturbance, and multiple cranial nerve palsies. Magnetic resonance imaging revealed a multicystic mass with hemorrhagic fluid-fluid levels in the right midbrain, suggesting the presence of a cavernous malformation. Diffusion tensor imaging showed the mass to be close to the right corticospinal tract and ipsilateral medial lemniscus. Subtotal removal of the mass was performed via a right subtemporal approach. The histopathological diagnosis was of a mixed germ cell tumor (GCT) comprising mature teratoma and germinoma cells with syncytiotrophoblastic giant cells. The patient underwent postoperative chemotherapy and radiotherapy, and no tumor progression was found during 1 year of follow-up. Intracranial GCTs arise mainly in the pineal and the suprasellar area. Germ cell tumors in the brainstem are rare, with only 12 reported cases. Among these, 4 were in the midbrain and histologically were pure germinomas. To the authors' knowledge, this is the first reported case of a mixed GCT in the midbrain combining mature teratoma and germinoma cells.

Primary cystic germinoma originating from the midbrain

A primary intracranial germinoma that involves the midbrain is rare. We describe an unusual case of primary cystic germinoma originating from the midbrain. A 29-year-old man presented with diplopia, and his MRI showed a cystic, ring-like enhanced lesion in the thalamo-mesencephalic junction. Open biopsy was performed and the diagnosis of germinoma was based upon the histopathological findings. Following chemotherapy and radiotherapy, the symptoms improved and the tumor disappeared. We propose that primary intracranial germinoma should be included in the differential diagnosis of midbrain tumors, because early diagnosis and appropriate treatment for midbrain germinoma improves clinical outcome.

Germ cell tumors of the brainstem: report on two cases with pulmonary complications and a review of the literature

Intracranial germ cell tumors most commonly present in the pineal and suprasellar regions. Rare cases of brainstem germ cell tumors have been described. Here, we present two cases with brainstem germ cell tumors and review the current literature. The two patients did well, in terms of disease control, but have significant morbidity related to respiratory issues. One patient remains ventilator dependent and the second died from respiratory arrest.

Primary midbrain germinoma

An 11-year-old boy presented with a 4-month history of progressive holocranial headache, intermittent vomiting and visual blurring. Later, he began walking unsteadily, with progressive bilateral visual and hearing loss. He had had two episodes of abnormal tonic posturing the day prior to admission. On examination, the patient was drowsy and did not respond to commands. Imaging showed an enhancing midbrain mass with an exophytic component with hydrocephalus. Emergency ventriculoperitoneal shunt was performed, following which there was neurological improvement. Later he underwent a midline suboccipital craniectomy with vermian splitting and decompression of the exophytic component of the tumor from the midbrain. Biopsy of the tumor revealed a germinoma. Post-operatively, the patient received chemotherapy followed by radiotherapy. Primary midbrain germinoma is an extremely rare entity and to the best of our knowledge only two cases to date have been reported in the literature.