Intracerebral schwannomas: a rare disease with varying natural history

A clinicopathological study of peripheral schwannomas

Aim and objective

Schwannomas are benign neoplasms of neural origin with sporadic or syndromic occurence. They are commonly seen in cranial nerves. Peripheral schwannomas occur rarely and may have unique presentations. The aim of this study is to evaluate the clinico-pathological characteristics of peripheral schwannomas.

Methods

A retrospective cross sectional study of peripheral schwannomas excluding head neck region was conducted. The study group consisted of 18 cases which were recorded over a period of seven years. The corresponding data were collected from the archives of the Department of Pathology.

Results

Male to female ratio was 1:1. The average age of the cases was 47 years. The most common site was the upper limbs (55.55%) followed by lower limbs, chest and penis. The lesions mostly presented as painless swellings (62%). Histopathological examination revealed classic features of schwannoma. Secondary changes included cystic degeneration, foam cells, epitheloid cells, hyalinization, microcystic change and collection of plasma cells. All cases were confirmed by positive S100 staining.

Conclusion

Peripheral schwannomas may be missed due to its rarity and atypical presentations. Both clinicians and pathologists should be aware of this common entity at unusual sites for the proper management of the patients. Surgery is usually the treatment of choice.

Fractionated Radiosurgical Treatment of Intracerebral Schwannoma: A Case Report and Literature Review

Intracranial schwannomas (ICS) unrelated to the cranial nerves are extremely rare; around 70 cases have been reported worldwide. The available literature consists of case reports and small series that present variable characteristics distinguishing these lesions. Brain parenchyma schwannomas are typically benign tumors with currently unknown origins. Diagnosis of intraparenchymal schwannoma is almost never made preoperatively. The management of these tumors usually consists of gross total resection, chemotherapy, and radiotherapy in cases of recurrence. The authors present a case of fractionated Gamma Knife radiosurgical treatment of intracerebral schwannoma following partial microsurgical resection.

Fluorescein-guided excision of a pediatric intraparenchymal schwannoma presenting with seizure and neurogenic pulmonary edema

Intraparenchymal schwannomas of the brain are very rare, accounting for < 1% of intracranial schwannomas. We present a case of an 11-year-old boy with a left frontotemporal lobe schwannoma presented with seizure and neurogenic pulmonary edema. To our knowledge, this is the first case of intracerebral schwannoma with neurogenic pulmonary edema published to date and is the first case of an intracerebral schwannoma operated with fluorescein guidance.

Occipital lobe epilepsy was presented in a patient with intracerebral schwannoma: a case report and literature review

Schwannoma arising within brain parenchyma is a rare scenario. So far, only 70 cases were reported. We reported a case of intracerebral schwannoma presented with occipital lobe epilepsy, which has never been reported before. A 19-year-old man suffered from intermittent blurred vision and headache. Neuroradiological findings showed a left occipital lesion with cystic and solid components. Histological and electron micrograph features confirmed the diagnosis of schwannoma after the tumor was totally removed. The theories and literature related to this case were reviewed and the possible developmental origin was discussed. We found that this kind of schwannoma is more often in adolescent and young adults.

Case of an Intracranial Malignant Peripheral Nerve Sheath Tumor in the Setting of Pacer-dependent Heart Block

Intracranial malignant peripheral nerve sheath tumors (MPNSTs) are an extremely rare entity with only a handful of cases reported in the literature. MPNSTs typically occur in the extremities and the trunk. The treatment algorithm includes, when possible, gross-total resection as these tumors are extremely aggressive. When these tumors occur intracranially, they are termed malignant intracerebral nerve sheath tumors. The diagnosis hinges on immunohistochemistry and pathological features and often the diagnosis can be delayed for this reason. In this setting, it is critical to utilize intraoperative navigation, thus necessitating the use of fine-cut magnetic resonance imaging (MRI). This report presents a patient who presented with symptoms of obstructive hydrocephalus secondary to an intracranial mass. The patient underwent a full and extensive metastatic workup that was ultimately negative. To complicate things, the patient was fully pacemaker dependent. In this report, we review the literature surrounding this type of tumor, along with a detailed presentation of the case mentioned including the difficulties of cardiac pacing in the setting of MRI.

Microcystic/Reticular Schwannoma of the Frontal Lobe: An Unusual Occurrence

Schwannoma is a benign peripheral nerve sheath tumor that typically involves cranial nerves of the head and neck region. Intraparenchymal occurrence of this tumor is uncommon. Even rarer in this site is the microcystic/reticular pattern of schwannoma. This histologic variant, first described in 2008, has a predilection for visceral organs. Herein, we report the first case of microcystic/reticular schwannoma of the frontal lobe.

Unusual Intracerebral Presentation of a Myxoid Neurofibroma

BACKGROUND

Neurofibromas are benign nerve sheath tumors that usually affect peripheral nerves and are related to neurofibromatosis type 1; however, they have not been described as a cause of intraparenchymal brain tumor.

CASE DESCRIPTION

We report a case of intracranial myxoid neurofibroma in a 19-year-old female patient manifested as an intense and progressive cephalea, followed by nausea, vomiting, photophobia, and phonophobia. Computed tomography and magnetic resonance imaging showed an extant, expansive left frontoparietal parafalcine/parasagittal tumor. Histopathologic examination determined S-100 protein and CD34 positivity, as well as sparse expression of Ki67 protein, and indicated Schwann cells with characteristic wavy nuclei and intraneural fibroblasts in a myxoid background. Together, these observations characterized the tumor as myxoid neurofibroma. The tumor was excised, and the patient recovered without deficits and with no signs of recurrence after 6 years of follow-up.

CONCLUSIONS

This is a novel presentation of a myxoid neurofibroma. The tumorigenesis mechanisms are likely complex and possibly involve the differentiation of Schwann cells present in adrenergic autonomic nerves in the subarachnoid arterial branches or in trigeminal nerves present in the meningeal convexity.

Histologic Evidence for Arteriovenous Malformation-Like Vasculature Occurring within an Intracerebral Schwannoma: A Case Report and Review of the Literature

BACKGROUND

The phenomenon of intracerebral schwannoma is exceedingly rare, and its etiology still a matter of debate. No documented cases of intracerebral schwannoma containing vascular elements consistent with those of an arteriovenous malformation (AVM) have been reported. We describe such a case here.

CASE DESCRIPTION

A left temporal intraparenchymal lesion was discovered incidentally in a 34-year-old man after he suffered a mild trauma. The lesion was resected and found on histologic examination to be an intracerebral schwannoma with AVM-like vasculature. The patient made a full recovery after resection.

CONCLUSIONS

To our knowledge, this is the first case of an intracerebral schwannoma with AVM-like characteristics to be reported in the literature. We hypothesize that the co-occurrence of this rare pathologic entity is caused by an interrelated etiologic process, with the tumor microenvironment of the schwannoma inciting the development of the vascular malformation.