Intraosseous schwannoma of the petrous apex

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.

Neurofibroma of the internal carotid artery cavernous sympathetic plexus: illustrative case

BACKGROUND

Intracranial carotid sympathetic plexus (CSP) nerve sheath tumors have rarely been reported in the literature. This study describes the first reported case of a CSP neurofibroma and the first case of a CSP nerve sheath tumor treated via an endoscopic endonasal approach followed by adjuvant radiosurgery.

OBSERVATIONS

A 53-year-old man presented with 3 days of headaches and diplopia and was found to have a complete left abducens nerve palsy. Computed tomography (CT) revealed a smoothly dilated left carotid canal, CT angiography revealed a superiorly displaced left internal carotid artery (ICA), and magnetic resonance imaging revealed a T2-hyperintense and avidly enhancing lesion in the left cavernous sinus encasing the ICA. The patient underwent subtotal resection via an endoscopic transsphenoidal transcavernous approach followed by Gamma Knife radiosurgery.

LESSONS

Nerve sheath tumors arising from the CSP are extremely rare but need to be considered when assessing unusual cavernous sinus lesions. The clinical presentation is dependent on the anatomical location of the tumor and its relationship to the ICA. The optimal treatment paradigm is unknown.

Intraosseous schwannomas involving the sacrum: Characteristic imaging findings and review of the literature

Background and purpose Sacral intraosseous schwannomas represent a rare subset of schwannomas. The existing literature detailing the radiographic appearance of intraosseous schwannomas is limited. The aim of this study is to formally characterize the radiological appearance of sacral intraosseous schwannomas to differentiate them from other lytic lesions. Materials and methods Imaging studies of 13 pathologically proven intraosseous schwannomas were reviewed from multiple institutions by fellowship-trained radiologists. A PubMed search was performed and identified four papers pertaining to the imaging characteristics of sacral intraosseous schwannomas. The results of these papers were compared to findings from our cases. Results All tumors had heterogeneous signals and were predominately solid but cystic components with fluid-fluid levels were present. The tumors caused a mass effect but none infiltrated the surrounding soft tissues. Post-contrast T1-weighted images revealed heterogeneous enhancement in all 13 tumors and four possessed non-enhancing cysts. A literature review identified 16 other cases of sacral intraosseous schwannomas forming a total of 29 cases examined. Conclusions Sacral intraosseous schwannomas should be considered in the differential diagnosis for both radiologists and pathologists when dealing with large expansile, lytic lesions, with well-defined sclerotic margins involving the sacrum. This is particularly important in middle-aged adults presenting with pathology centered around S2-3.

Intraosseous Schwannoma of the Petrous Apex

Background and Importance Intraosseous schwannoma is a relatively rare clinical entity that typically arises in vertebral and mandibular bone. Intraosseous schwannoma located entirely within the petrous bone is exceedingly rare, and only two cases have been reported to date.

Clinical Presentation A 47-year-old Asian man was referred to our hospital with a chief complaint of double vision. Neurologic examination revealed left abducens nerve palsy. Radiologic imaging showed a 35-mm osteolytic expansive lesion located in the left petrous apex. We made a preoperative diagnosis of chondrosarcoma and performed surgical resection. Surgery was performed via a left subtemporal epidural approach with anterior petrosectomy. The histopathologic diagnosis of the tumor was schwannoma. Schwannoma arising from cranial nerves was excluded from intraoperative findings in conjunction with the results for cranial nerves, and intraosseous schwannoma was diagnosed. Postoperative course was uneventful, and abducens nerve palsy resolved immediately after surgery.

Conclusion The differential diagnosis of intraosseous schwannoma should be considered for an osteolytic mass lesion within the petrous apex. Subcapsular tumor removal was considered ideal in terms of preservation of the cranial nerves and vessels around the tumor.

Spinal cord compression revealing an intraosseous schwannoma

A 68-year-old female presented with inflammatory lumbalgia and cruralgia. Physical examination revealed a lumbar stiffness without neurological deficit. Secondarily, paraplegia and urinary retention appeared. Magnetic resonance imaging showed a vertebral compaction of L3 vertebra with medullar compression. Emergent surgery revealed an epidural tumor involving largely the L3 vertebral body. Histology found schwannoma with positive protein S100 on the immunohistochemical study. Metastasis screening revealed bilateral nodular lesions of the lungs and a trochanter high scintigraphic signal. It was a malignant schwannoma. The patient underwent radiotherapy in addition to the total tumor resection.