Epidermoid tumor of the pons

Epidermoid cyst of central nervous system: A case series and review of literature

INTRODUCTION

Epidermoid cysts, originating from ectodermal cell remnants during embryogenesis, are rare, slow-growing tumours commonly found in the cerebellopontine angle, fourth ventricle, and sellar/parasellar regions. This retrospective study explores clinicopathological features, demographics, and radiological details of fifteen central nervous system epidermoid cyst cases over three years.

MATERIALS AND METHODS

Histologically confirmed cases undergoing surgical excision from July 2020 to July 2023 were retrospectively evaluated. Patient age, clinical presentations, radiological features, and histopathological findings were analyzed using descriptive statistics and aligned with the PROCESS criteria.

RESULTS

Fifteen cases, spanning various age groups and clinical presentations, were included. There were four cases each in the posterior fossa and cerebellopontine angle, three in temporal region, two in intraspinal region, and one each in the retromastoid intra-diploic and third intra-ventricular region. Lesions exhibited diverse distribution, gross findings, and microscopic features. Radiological imaging exhibited well-defined hypo-attenuated masses on computed tomography and contributed to the preoperative diagnosis in eight cases. Despite challenges in complete excision due to adherence, 13 cases underwent successful resection. Chemical meningitis, a common postoperative complication, underscores the importance of meticulous surgery.

CONCLUSION

This study highlights clinicopathological characteristics, challenges in surgical management, and postoperative complications of central nervous system epidermoid cysts. Comparative analysis with existing literature emphasizes the uniqueness of epidermoid cysts, differentiating them from craniopharyngiomas and dermoid cysts. Despite the retrospective design, valuable insights are provided, emphasizing the need for prospective studies. Effective management involves complete excision, ensuring long-term remission and emphasizing the distinctive nature of these intriguing intracranial lesions.

Intraparenchymal epidermoid cyst: proper surgical management may lead to satisfactory outcome

Intraparenchymal epidermoid cysts (IECs) are rare lesions, thus the preoperative diagnosis and proper surgical management are still a challenge. We searched the database at our institution and performed a search of English literature in PubMed and Google Scholar. Keywords used were as follows: "intraparenchymal"; "intracerebral"; "intraaxial"; "epidermoid cyst"; "brainstem"; "cholesteatoma"; "pearly tumor". Only cases that were true intraparenchymally located and contained adequate clinical information were included. Six cases of IECs were recorded at our institution. Total removal was achieved in all the six patients with good outcomes. 29 cases meeting the above criteria were found in the literature. Including ours, a total of 35 patients were analyzed. Females were more frequently affected (F/M ratio, 1.9:1). Most of them were located in the brainstem (42.9%) and temporal lobe (22.9%). While in children, all were located in the brainstem. 45.2% showed subtle peripheral enhancement on Magnetic Resonance Imaging (MRI), and all appeared hyperintense on Diffusion Weighted Imaging (DWI). In the subgroup of cerebral lobes and cerebellums, total resection was achieved in 89.5%, and they all showed good outcomes. While in the subgroup of brainstem, 46.7% (seven cases) underwent total resection and 50% (three cases) of them died postoperatively. MRI with DWI is helpful in the preoperative diagnosis. Total resection should be achieved for the IECs located in cerebral lobes and cerebellums, while subtotal resection is a wise and safe strategy for the IECs located in the brainstem.

An analysis of intracranial epidermoid tumors with malignant transformation: treatment and outcomes

OBJECTIVE

While typically benign, epidermoid tumors upon rare occasion can undergo malignant transformation, which carries a poor prognosis. Here, we reviewed treatment strategies and analyzed outcomes for every case of malignant epidermoid tumor reported since its original description in 1912.

METHODS

A comprehensive literature review identified all reported cases of malignant transformation of intracranial epidermoid tumor. Treatments were categorized as follows: palliative management, stereotactic radiosurgery (SRS), chemotherapy, and surgery plus multiple (2+) adjuvant therapies. Survival data of these groups were compared to treatment outcomes for patients receiving only surgical resection, as reported in our previous study.

RESULTS

We identified 58 cases of intracranial epidermoid tumor with malignant degeneration. Average survival regardless of therapy was 11.8 months. Mean survival outcomes for groups treated with palliative management, chemotherapy, SRS, and multiple postoperative adjuvant therapies were 5.3 months, 25.7 months, 29.2 months, and 36.3 months, respectively. Outcomes for the groups including SRS, chemotherapy, and multiple post-operative adjuvant therapies were statistically significant compared to surgical resection alone.

CONCLUSION

While there remains a lack of consensus regarding the best approach to the management of patients with malignant epidermoid tumors, our systematic analysis characterizes and confirms the added benefit of SRS, chemotherapy, and multimodal adjuvant therapies.

Clinical characteristics and diagnostic imaging of epidermoid tumors

Epidermoid tumors are rare, benign congenital lesions which typically present between the third and fifth decades of life. They are thought to originate from ectodermal cells misplaced during neural tube formation and separation. While epidermoids may present anywhere in the cranial vault, they are characteristically located intradurally and in a paramedian position within the cerebellopontine angle and parasellar regions. Although imaging results may vary depending upon cystic content, CT scanning generally reveals a well-circumscribed, nonenhancing, lobulated, hypodense mass. They are hypointense on T1-weighted MRI, and hyperintense on T2-weighted MRI, diffusion-weighted imaging and fluid-attenuated inversion recovery sequences. The use of appropriate neuroimaging should be utilized to differentiate epidermoids from other intracranial lesions. While gross total resection of these tumors is the definitive treatment to prevent recurrence and aseptic meningitis, a subtotal resection may be necessary to preserve neurological function.

[Orbital epidermoid cyst. Case report]

Epidermoid tumors represent 1% of all primary intracranial tumors. Most of them occur intradurally in cerebellopontine angle and parasellar citerns. The intra-orbital location accounts for 4 to 5% of all primary intra-orbital tumors. We report the case of a 23-year-old girl with progressive right proptosis who had developed 6 months earlier. The tumor was removed via an external orbitotomy approach. Histology confirmed the diagnosis.

Brainstem epidermoid cyst in a child. Case report

A 10-year-old girl presented with a brainstem epidermoid cyst manifesting as dysphagia and post-prandial vomiting. Magnetic resonance imaging disclosed a cystic mass in the brainstem with associated hydrocephalus. She was treated under a presumptive diagnosis of abscess until the definitive histological diagnosis was established at the fourth admission. In spite of four interventions, she remained in good condition with minimal cranial nerve pareses. Subtotal removal of the epidermoid cyst in the brainstem results in recurrence within a relatively short period, especially in children. Total resection of the tumor is the optimum treatment. The differential diagnosis includes abscess, cystic glioma, and neurenteric cyst.