Solitary intraosseous schwannoma of the base and vault of the skull: a summary review of such unusual location

Intraosseous Schwannoma of the Frontal Bone: A Case Report and Review of the Literature

Intraosseous schwannoma is a rare diagnosis, particularly so in the skull. Accordingly, little data exists to unify common features of this disease. Here, we present the fourth known case of a primary intraosseous schwannoma of the frontal bone: a 46-year-old male with severe, progressive headache and an osteolytic frontal bone lesion. Gross total resection of the lesion was performed with excellent clinical outcome. Histological analysis confirmed the diagnosis. The limited existing literature on this topic was reviewed to identify emerging trends surrounding presenting symptoms and treatment. Early literature suggests symptoms are often nonspecific, except for lesions of the petrous apex. No cases of recurrence have been demonstrated after gross total resection, though incomplete resection has been associated with recurrence. This diagnosis appears to be becoming a more often-considered differential for osteolytic, expansile skull lesions.

Intraosseous schwannoma in the clivus mimicking chordoma treated with endoscopic endonasal surgery: A case report

Background:

Intraosseous schwannomas are extremely rare and they have not yet been reported to occur in the clivus. We report a schwannoma in the clivus mimicking chordoma and review intraosseous schwannomas of the skull.

Case Description:

A 62-year-old man presented with gradually worsening hoarseness with dysphagia and atrophy of the left tongue, trapezius muscle, and sternocleidomastoid muscle. Magnetic resonance imaging showed that the tumor was mainly located in the clivus, and a computed tomography (CT) scan revealed an osteolytic lesion with expansion of the clivus and preservation of the bony cortex. Endoscopic endonasal surgery was performed to diagnose and treat symptoms. The tumor was subtotally removed without any complications. The histopathological findings revealed typical schwannoma, which showed Antoni A and Antoni B patterns positive for S100 protein. Based on the preoperative imaging, intraoperative and histopathological findings, the tumor was considered to be an intraosseous schwannoma in the clivus, and no recurrence was observed after 1 year of postoperative follow-up.

Conclusion:

Even though the intraosseous schwannoma in the clivus is uncommon, it should be considered as a differential diagnosis if an expansive lesion without destruction of the cortical bone is shown on CT as well as iso-hyperintensity on T2-weighted magnetic resonance imaging.

Fibrous granulation mimicking cranial intraosseous tumor

A cranial intraosseous lesion is a rare disease with a limited number of subtypes. We report a case of a cranial intraosseous fibrous granulation that mimicked an intraosseous tumor. A 57-year-old man was incidentally found to have a cranial intraosseous lesion on brain computed tomography. Total resection was performed to establish a pathological diagnosis and to achieve cosmesis, and the pathological diagnosis was fibrosis and fibrous granulation in the medullary cavity. Fibrous granulation tissue occurs in the calvarium due to bone defects secondary to acquired factors, including trauma. Since its pathological diagnosis is established through surgery, surgery should be carefully considered based on the patient's chief complaint, location of the lesion, and suspicion of malignancy based on imaging findings.

Curious Case of Acoustic Schwannoma of Middle Cranial Fossa: A Case Report

Acoustic neuromas are the most common lesion in the cerebellopontine angle. The authors report a unique case of acoustic schwannoma, presenting in middle cranial fossa masquerading as meningioma in a 24-year-old man, presenting with headache and focal seizures. Contrast-enhanced MRI of the brain revealed a mass lesion of the right middle cranial fossa consistent with features of meningioma. Intraoperatively a well-defined tumor with attachment to anterior petrous bone was excised. In the immediate postoperative period, the patient developed right-sided hearing loss, which was proven to be retrochoclear hearing loss on brainstem evoked response audiometry. Histopathology findings were consistent with benign schwannoma. Acoustic schwannoma originating in an unusual location middle cranial fossa is a plausible explanation of such unusual occurrence. Such a case has never been reported in the literature.

Successful Management of Intrathoracic Phrenic Malignant Peripheral Nerve Sheath Tumor by Multimodal Treatment

Malignant peripheral nerve sheath tumors (MPNSTs) are rare and can be associated with type 1 neurofibromatosis. They are rarely located at the mediastinum, most often at the posterior mediastinal compartment or the paravertebral gutters. MPNSTs of the anterior mediastinum arising from the phrenic nerve are exceptional. Their prognosis is poor due to the high potential of local tumor recurrence and metastasis. Complete surgical resection remains the only radical treatment. However, the outcomes after this treatment alone cannot be considered satisfactory. Preoperative chemotherapy could be an interesting therapeutic option for unresectable tumors. We report here the case of a 77-year-old woman with an MPNST located at the anterior mediastinum arising from the phrenic nerve. This tumor was successfully managed with multimodal therapy combining preoperative chemotherapy, complete surgery and adjuvant radiation.

Intraosseous schwannoma of the occipital bone: a case report

OBJECT

Intraosseous schwanomma of the calvarium METHODS: This paper reports the case of a 7-year-old boy who presented with an intraosseous schwanomma involving the occipital bone and provides a brief overview of the literature.

RESULTS

The patient presented with a mass in the midline occipital region. Neuroimaging revealed a lytic lesion in the occipital bone with lack of enhancement on gadolinium MRI sequences. A gross total resection was performed, and histopathological analysis confirmed the diagnosis of schwannoma.

CONCLUSION

Intraosseous schwanomma should be considered in the differential diagnosis of skull vault lesions in the pediatric population and can be successfully managed with surgical excision.