Olfactory Nerve Schwannoma: A Case Report and Review of the Literature

Esophageal schwannoma mimicking non-functional parathyroid adenoma on 99mTc-sestamibi imaging: a case report

Technetium-99m sestamibi single-photon emission computed tomography/computed tomography (99mTc-sestamibi SPECT/CT) is a mainstay of the pre-operative localization of parathyroid lesions. We report here the case of a 30 year-old woman with a fortuitously discovered 2 cm cervical mass for which a parathyroid origin was originally suspected due to its retro-thyroidal localization and a personal history of nephrolithiasis. Normal serum calcium and parathyroid hormone (PTH) levels excluded primary hyperparathyroidism, raising suspicion of a non-functional parathyroid adenoma, and SPECT/CT imaging showed that the mass was 99mTc-sestamibi-avid. Fine-needle aspiration (FNA) was performed; cytology was non-diagnostic but the needle washout was negative for thyroglobulin, calcitonin and PTH, arguing against a thyroidal or parathyroidal origin of the mass. Core needle biopsy revealed a schwannoma, ostensibly originating from the recurrent laryngeal nerve; upon surgical resection, it was finally found to arise from the esophageal submucosa. This case illustrates the fact that endocrinologists, radiologists, nuclear medicine, head and neck, and other specialists investigating patients with cervical masses should be aware that schwannomas need to be considered in the differential diagnosis of focal 99mTc-sestamibi uptake in the neck region.

Olfactory Groove Schwannoma or Olfactory Ensheathing cell Tumor?

BACKGROUND

Schwannomas are benign tumors that arise from Schwann cells. Rare cases are shown to arise from the olfactory nerve. The genesis of Olfactory groove schwannoma (OGSs) is still puzzling. Yusda et al hypothesized that olfactory ensheathing cell tumors (OECTs) might be the origin of OGSs.

CLINICAL PRESENTATION

Here, the authors report the case of a 59-year-old woman who presented with a paroxysmal headache for 1 year. The tumor appeared as hypointensity on T1-weighted images, hyperintensity on T2-weighted, and exhibited strong, heterogeneous enhancement. The tumor was removed through a lateral supraorbital approach. The final pathologic diagnosis was schwannoma. The postoperative period was uneventful after 4 months, and the headache disappeared.

DISSCUSSION AND CONCLUSION

OGSs and OECTs are extremely rare. There are many similarities in clinical manifestations, images, and pathologic findings. OGSs are difficult to distinguish from OECTs.

Management of non-vestibular schwannomas in adult patients: a systematic review and consensus statement on behalf of the EANS skull base section. Part I: oculomotor and other rare non-vestibular schwannomas (I, II, III, IV, VI)

BACKGROUND

Non-vestibular schwannomas are relatively rare, with trigeminal and jugular foramen schwannomas being the most common. This is a heterogeneous group which requires detailed investigation and careful consideration to management strategy. The optimal management for these tumours remains unclear, and there are several controversies. The aim of this paper is to provide insight into the main principles defining management and surgical strategy, in order to formulate a series of recommendations.

METHODS

A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the surgical management of these tumours on a European perspective. To achieve this, the task force performed an extensive systematic review in this field and had discussions within the group. This article is the first of a three-part series describing non-vestibular schwannomas (I, II, III, IV, VI).

RESULTS

A summary of literature evidence was proposed after discussion within the EANS skull base section. The constituted task force dealt with the practice patterns that exist with respect to pre-operative radiological investigations, ophthalmological assessments, optimal surgical and radiotherapy strategies and follow-up management.

CONCLUSION

This article represents the consensually derived opinion of the task force with respect to the treatment of non-vestibular schwannomas. For each of these tumours, the management of these patients is complex, and for those which are symptomatic tumours, the paradigm is shifting towards the compromise between function preservation and progression-free survival.

[Olfactory (subfrontal) schwannoma: case report and literature review]

BACKGROUND

Olfactory nerve schwannomas are extremely rare. Their origin is still unclear, since olfactory nerve has no Schwann cells. There are about 70 case reports of olfactory nerve schwannoma in the world literature. Original articles devoted to this issue are currently absent.

RESULTS

We present a 55-year-old patient with olfactory nerve schwannoma who underwent surgery at the Federal Center of Neurosurgery in Novosibirsk. MRI revealed extracerebral mass lesion of anterior cranial fossa base with left-sided lateralization resembling meningioma of the olfactory fossa. The patient underwent microsurgical resection of mass lesion of anterior cranial fossa base through left-sided lateral supraorbital craniotomy. The tumor macroscopically resembled schwannoma. Total resection was carried out. Considering morphological structure and immunomorphological characteristics, we verified schwannoma Grade 1.

CONCLUSION

Olfactory nerve schwannomas are rare tumors with benign histological structure. Relapses after total resection are unlikely. However, further research of this rare pathology and long-term postoperative follow-up are required.

A Case of Schwannoma in Subfrontal Area and Nasal Cavity

Schwannoma is a benign solitary neoplasm emerging from the Schwann cells of the peripheral, cranial and autonomic nerves. Approximately 25 to 45% of schwannomas occur in the head and neck region. However, schwannoma in the subfrontal area, nasal cavity or paranasal sinus is very rare and accounts for only 4% of these neoplasms. We experienced a case of schwannoma in the subfrontal area and left nasal cavity in a 74-year-old man who complained of recurrent rhinorrhea. We report this unusual case of schwannoma with a review of the literature.

Unusual Sites for Extracranial Head-Neck Schwannomas

Schwannomas are a frequent cause of swellings in the head and neck region. Due to the abundance of peripheral, cranial and autonomic nerves in this region, schwannomas can present in variety of locations, posing a diagnostic and therapeutic challenge to the surgeon. Unusual sites in head and neck region can have varied presentation depending on the site of origin. We identified unusual extracranial locations of head and neck schwannomas, their presenting features and surgical management. Retrospective review of cases of extracranial head and neck schwannomas operated in the Department of Otolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, New Delhi, a tertiary referral centre between July 2015 and June 2019. A total of 42 cases of extracranial head and neck schwannomas were operated. Among them, 9 cases were found to arise from uncommon sites, such as parotid gland (n = 1), infratemporal fossa (n = 2), external auditory canal (n = 1), subglottis (n = 1), false vocal cord (n = 1), frontal recess (n = 1), maxillary sinus (n = 1) and retromolar trigone (n = 1). All patients underwent excision via relevant approaches. Nerve of origin was identified in 4/9 cases. One case had postoperative neurological deficit. No recurrences were noted in mean follow-up of 19 months. Schwannomas ought to be considered as a differential diagnosis for swellings/ mass in any part of head and neck region. Comprehensive evaluation with appropriate imaging and histology should be done in all cases. Preoperative counselling and consent regarding neurological deficit pertaining to possible nerve of origin is required in each case.

Anterior skull base olfactory tumours, which is what? A case report and review

Intracranial schwannomas not originating from cranial nerves are rare. In this paper, we report a case of a 50-year-old male who presented with worsening headaches, diplopia and nausea over two years. Radiological imaging revealed a large tumour arising from the olfactory groove region with a preoperative diagnosis of olfactory groove meningioma (OGM). Intraoperatively, the tumour originated from the region of the attachment of the falx to the crista galli. The patient recovered without complication and histopathology reported an unexpected diagnosis of WHO Grade 1 schwannoma. However, as olfactory groove schwannomas (OGSs) cannot be distinguished from olfactory ensheathing cell tumours (OECTs), it is possible that the tumour could have been either an OGS or an OECT. Distinguishing between OGSs, OECTs and OGMs preoperatively is difficult. OGMs exhibit distinct histopathological features from OGSs/OECTs, however, OGSs and OECTs currently cannot be distinguished from each other. Here, we review the literature to discuss the differentiating features and cellular origins of these three tumours.

A Rare Case of Schwannoma Arising from the Dura Mater of the Petrosal Surface in the Posterior Cranial Fossa

BACKGROUND

An intracranial schwannoma originating in the dura mater is extremely rare. Herein, we report a case of schwannoma arising from the dura mater of the petrosal surface in the posterior cranial fossa.

CASE DESCRIPTION

A 48-year-old man presented with slight gait disturbance and papilledema. Magnetic resonance imaging showed a T1- and T2-weighted mixed-intensity extra-axial tumor, approximately 4 cm in the maximum diameter with multiple small cysts, in the left posterior cranial fossa. The tumor was heterogeneously enhanced with gadolinium. Operative findings via a lateral suboccipital approach revealed that the tumor did not adhere to any cranial nerves but to the dura mater of the petrosal surface. The tumor was completely excised without any neurologic deficits, and the histologic diagnosis was schwannoma.

CONCLUSIONS

The operative and postoperative findings suggested that the schwannoma originated in the meningeal branch of the lower cranial nerves or upper cervical nerves in the dura mater of the petrosal surface in the posterior cranial fossa.