Rare Cranial Nerve Schwannomas: A Retrospective Review of Nontrigeminal, Nonvestibular Cranial Nerve Schwannomas

A, Rao KVLN, Somanna S. Surgical Management of Large (≥3 cm) Trigeminal Schwannomas: Functional Outcomes and Approach Selection in Multicompartmental Schwannomas

Introduction  Trigeminal schwannoma surgery has shown a remarkable improvement in functional recovery and tumor resection. In the era of radiosurgery, these outcomes need to be characterized for tumors which are outside the realm of being treated with radiosurgery. We present a series of trigeminal schwannomas larger than 3 cm, surgical approaches used, and outcomes with an emphasis on functional recovery in a high-volume center with radiosurgery facilities. Method  All consecutive cases of trigeminal schwannoma from January 2012 to May 2021 which were more than 3 cm in size and underwent microsurgery were included in this series. The surgical approach, neurological outcomes, and extent of resection were defined objectively with pre/postoperative magnetic resonance imaging. Results  A total of 83 such cases (>3 cm) were found, with cranial nerve symptoms (5th most common) being the commonest. Twenty three percent cases had blindness due to secondary optic atrophy and eighteen percent had long tract motor symptoms signifying the tumor burden in our series. Radiological gross total excision was achieved in 75.9% cases. Conclusion  Large-volume schwannomas present with cranial nerve involvement and may need extensive skull base approaches. Functional outcomes need to be prioritized and can be achieved albeit with lesser gross resection rates. Hearing and facial preservation in addition to relief of trigeminal symptoms should be the goal of resection with minimal additional morbidity.

Intraparenchymal Schwannoma of Temporal Lobe: A Case Report and Review of the Literature

Intracranial schwannomas (ISs) account for approximately 8% of intracranial tumors, while IS, a rare entity, is responsible for roughly 1% of IS. A 33-year-old man with a 3-month headache and sudden onset seizure was referred to our clinic. Preoperative magnetic resonance imaging revealed a contrast-enhancing mass accompanied by cystic components in the right temporal lobe. Ganglioglioma, metastasis, or glioblastoma multiforme was suspected, and surgery was advised. During surgery, gross total resection of a noninvasive tumor was conducted. Postoperative recovery was uneventful. Based on histopathological examination and confirmatory immunohistochemistry, the intraparenchymal temporal tumor was diagnosed as schwannoma. ISs are extremely scarce brain tumors mainly located on the surface of the brain or adjacent brain ventricles. The definite preoperative diagnosis of schwannoma cannot be readily established due to radiologically indistinguishable features from metastasis and gliomas; however, histopathology and immunohistochemistry are of great assistance. Complete surgical removal is the most preferred treatment alternative with a long-term favorable prognosis without adjuvant and neoadjuvant chemotherapy requirements.

A Sporadic Cisternal Cystic Oculomotor Schwannoma-Case Report and Review of Literature

Schwannoma arising from a pure motor cranial nerve in sporadic cases is a rare finding. We report adult female patient presented with a seizure without oculomotor palsy. On evaluation, she was diagnosed with cystic oculomotor schwannoma and underwent surgery. She developed oculomotor palsy postoperatively. Here, we describe a rare sporadic cystic oculomotor schwannoma.

Cisternal oculomotor schwannoma: a rare cause of anisocoria with ptosis in a child

Background

Primary nerve sheath tumor of cranial nerve is a rare intracranial space occupying lesion that most commonly involves vestibular nerve. Oculomotor nerve schwannoma, without neurofibromatosis, is an extremely uncommon entity especially in children. Though any cranial nerve can be involved by schwannoma except I and II nerve as these cranial nerves lack a Schwann cell sheath.

Case presentation

We herein report a 14-year-old boy presenting with an oculomotor schwannoma in the absence of features of neurofibromatosis, manifesting as progressive diplopia, ptosis, and blurring of vision.

Conclusions

Most similar previous case reports in literature reported oculomotor schwannoma in adults, unlike our case. The detection rate of such rare lesions has, however, increased in the last two decades due to neuroimaging advances.

Trends in the Management of Non-Vestibular Skull Base and Intracranial Schwannomas

The aim of this review is to analyze the latest trends in the management of non-vestibular skull base and intracranial schwannomas in order to optimize tumor control and quality of life. Non-vestibular cranial nerve schwannomas are rare lesions, representing 5–10% of cranial nerve schwannomas. Management decisions should be individualized depending on tumor size, location and associated functional deficits. Generally, large sized schwannomas exerting significant mass effect with increased intracranial pressure are treated surgically. In some cases, even after optimal skull base resection, it is not possible to achieve a gross total resection because tumor location and extent and/or to reduce morbidity. Thus, subtotal resection followed by stereotactic radiosurgery or fractioned radiotherapy offers an alternative approach. In certain cases, stereotactic radiosurgery or radiotherapy alone achieves good tumor control rates and less morbidity to gross total resection. Finally, given the slow growth rate of most of these tumors, observation with periodic radiographic follow-up approach is also a reasonable alternative for small tumors with few, if any, symptoms.

Oculomotor schwannoma causing a progressive complete third-nerve palsy

A 69-year-old woman presented with an 8-month history of diplopia and examination findings consistent with a right third-nerve palsy. Head MRI identified the presence of a 5.8 mm, nodular, isointense lesion in the suprasellar cistern, which demonstrated enhancement with gadolinium contrast. The lesion did not show any evidence of growth over a 3-month follow-up period. These MRI findings, alongside the clinical features, suggest oculomotor nerve schwannoma. Oculomotor schwannomas are a rare cause of third-nerve palsy. The presenting features and management options for oculomotor schwannomas are discussed to provide a framework for the diagnosis and management of these patients.

Meningioma in a Postrenal Transplant Case: More than Meets the Eye

BACKGROUND

Patients with a renal transplant are an ever-increasing demographic. Their life expectancy is also on the rise and thus malignancies or tumors in these cases are more frequent. These patients are often on immunosuppressive drugs that are known to cause changes in the microvasculature, especially of the deep white matter. However, benign dural-based lesions are a rarity in these cases with very few (<5) ever being reported. Imaging findings in such cases are altered, which leads to an altered set of differential diagnosis.

CASE DESCRIPTION

We present a case of a right parasagittal lesion in case of postrenal transplant with imaging findings suggestive of an inflammatory lesion. The lesion was excised and histopathology was that of a fibrous meningioma. Pathological basis of altered imaging is discussed and potential causes elaborated along with a thorough review of similar cases and their findings.

CONCLUSIONS

Renal transplants and long-term survival are now a reality; calcineurin inhibitors are a staple for these cases. The drugs alter imaging findings and hence cases need to be carefully evaluated with a host of differential diagnosis. Knowledge of these changes is now necessary for these new spectra of cases.