Micro-invasive squamous cell carcinoma arising in a pre-existing intraventricular epidermoid cyst. Case report and literature review

Whole Exome Sequencing of Intracranial Epidermoid Cysts Reveals Immune-Associated Mechanistic and Potential Targets

Background/Objectives: Intracranial Epidermoid Cysts (IECs) are rare intracranial tumors primarily treated through surgery. Cyst adherence complicates complete removal, leading to high rates of tumor progression after subtotal resection. The molecular drivers of IEC remain unknown. Consequently, advances in treatment have fallen short. Tumor genetic profiling has revealed potential targets for drug development, including FDA-approved options and reshaping treatment. The genetic landscape of IECs has not been explored. We applied Whole Exome Sequencing (WES) to IECs to gain insights into the mechanisms of oncogenesis and identify potential therapeutic targets. Methods: We performed WES on tumor tissue and matched blood samples, when available. Following GATK best practices, we conducted read processing, quality control, somatic variant calling, and copy-number inference. Data analyses and visualization were conducted in R. Results: Top altered genes are associated with the immune system and tumor microenvironment, suggesting a mechanism of immune evasion. Gene and pathway enrichment revealed a high mutation burden in genes associated with Extracellular Matrix (ECM) and PI3K-AKT-mTOR cascades. Recurrent and deleterious alterations in NOTCH2 and USP8 were identified in 50% and 30% of the cohort, respectively. Frequent amplifications in deubiquitinases and beta-defensins strengthened the involvement of immune mechanisms for oncogenic transformation. Conclusions: Top altered genes and recurrent mutations may play a role in shaping the microenvironment and modulating immune evasion in IECs. USP8 and NOTCH2 may serve as clinically relevant target for IECs. Finally, we present evidence that the crosstalk between the PI3K-Akt-mTOR and ECM signaling pathways may play a role in modulating the immune escape mechanism in IECs.

Malignant Transformation of an Intracranial Epidermoid Cyst 25 Years After Initial Surgery: A Case Report and Systematic Review

OBJECTIVE

We report a unique case of a suspected recurrent intracranial epidermoid cyst (EDC) that was found on pathology to have undergone malignant transformation to squamous cell carcinoma (SCC) approximately 25 years after initial resection. Additionally, we performed a systematic review including 94 studies reporting intracranial EDC to SCC transformation.

METHODS

Ninety-four studies were included in our systematic review. PubMed, Scopus, Cochrane Central, and EMBASE were searched in April 2020 for studies regarding histologically confirmed SCC arising within an EDC. Kaplan-Meier estimations were used to estimate time to event including survival, and log rank tests were used to test for significance. All analyses were conducted using STATA 14.1 (StataCorp, College Station, Texas, USA); tests were two-sided, and statistical significance was defined using the alpha threshold of 0.05.

RESULTS

The overall median time to transformation was 60 months (95% confidence interval {CI}, 12-96). Transformation time was significantly shorter in the no surgery group (10 months, 95% CI undefined) versus the other 2 groups (60 months, 95% CI, 12-72 in surgery only and 70 months, 95% CI, 9-180 in surgery + adjuvant therapy group, both P < 0.01). Overall survival was significantly longer in the surgery + adjuvant therapy group (13 months, 95% CI, 9-24) versus the other 2 groups (3 months, 95% CI, 1-7 in surgery only and 6 months, 95% CI, 1-12 in the no surgery group, both P < 0.01).

CONCLUSIONS

We report a rare case of delayed malignant transformation of an intracranial EDC to SCC, occurring nearly 25 years after initial resection. Transformation time in the no-surgery group was statistically significantly shorter as compared to the surgery only and surgery + adjuvant therapy groups. Overall survival was statistically significantly higher in the surgery + adjuvant therapy group as compared to the surgery only and no surgery groups.

Radio-pathological characteristics of malignant transformation of an epidermoid cyst in the cerebellopontine angle: A case report

Background

Intracranial epidermoid cysts are rare congenital neoplasms that are clinically indolent and histologically benign. They rarely show malignant transformation, and several such cases have been reported. Some radiological features that suggest malignant transformation have been reported. However, histopathological features that indicate a high risk of malignant transformation have not been reported to date.

Case Description

We report a 59-year-old woman with a benign epidermoid cyst in the cerebellopontine angle that showed malignant transformation after 6 years. Magnetic resonance imaging (MRI) at the time of initial onset displayed a high-intensity signal on diffusion-weighted imaging (DWI), no peritumoral edema, and no enhancement on contrast-enhanced T1-weighted imaging. On the other hand, MRI at the time of malignant transformation showed a low-intensity signal on DWI, peritumoral edema, and enhancement of the tumor capsule on contrast-enhanced T1-weighted imaging. Pathological findings at the time of the first surgery differed from normal benign epidermoid cysts, in that stratified squamous epithelial metaplasia was observed, and immunohistochemical (IHC) analysis showed positive p53 staining. In addition, IHC analysis at the time of malignant transformation demonstrated positive p16 staining.

Conclusion

In benign epidermoid cysts, it is considered to cause malignant transformation when squamous metaplasia or p53 mutation is observed. Therefore, strict follow-up is required while paying attention to the characteristic changes in MRI for early detection and timely treatment of malignant transformation.

Primary Squamous Cell Carcinomas Arising in Intracranial Epidermoid Cysts: A Series of Nine Cases and Systematic Review

Objective

Primary squamous cell carcinomas (PSCCs) arising in intracranial epidermoid cysts (IECs) are very rare, and their management and prognostic factors remain unclear. This study aimed to enunciate the clinical features and suggest a treatment protocol based on cases from the literature and the cases from our institution.

Methods

The clinicoradiological data were obtained from nine patients with PSCCs arising in IECs, who underwent surgical treatment at Beijing Tiantan Hospital between July 2012 and June 2018. We also searched the PubMed database using the keywords “epidermoid cyst(s)” or “epidermoid tumor(s)” combined with “malignant” or “malignancy” or “intracranial” or “brain” or “squamous cell carcinoma” between 1960 and 2020. Risk factors for overall survival (OS) were evaluated in the pooled cohort.

Results

The mean age of our cohort was 51.2 ± 8.3 years (range: 39–61 years), which included eight males and one female. Gross total resection (GTR) was achieved in three patients, while non-GTR was achieved in six patients. Radiotherapy was administered to five patients. After a median follow-up of 16.7 ± 21.6 months (range: 3–72 months), eight patients died with a mean OS time of 9.75 ± 6.6 months (range: 3–23 months). In the literature between 1965 and 2020, 45 cases of PSCCs arising in IECs were identified in 23 males and 22 females with a mean age of 55.2 ± 12.4 years. GTR, non-GTR, and biopsy were achieved in six (13.3%), 36 (80%), and three (6.7%) cases, respectively. After a mean follow-up of 12.7 ± 13.4 months (range: 0.33–60 months), 54.1% (20/37) patients died, and recurrence occurred in 53.6% (15/28) patients. A multivariate analysis demonstrated that postoperative radiotherapy (p = 0.002) was the only factor that favored OS. The Kaplan–Meier analysis showed that, compared with no radiotherapy (median survival time: 4 months), radiotherapy (median survival time: 24 months) had significantly prolonged OS (p = 0.0011), and GTR could not improve OS (p = 0.5826), compared with non-GTR. The 1-year OS of patients with or without radiotherapy was 72.5% or 18.2%, respectively.

Conclusion

Malignant transformation of IEC into PSCC was prevalent in elderly patients, with slight male predominance. GTR of previous benign IECs is recommended. For remnant benign IECs, close follow-up should be performed. Postoperative radiotherapy for PSCCs could bring survival benefit. GTR of these malignant intracranial tumors is difficult when they involve important brain structures. Future studies with larger cohorts are necessary to verify our findings.

Intracranial squamous cell carcinoma arising in a cerebellopontine angle epidermoid cyst: A case report and literature review

RATIONALE

Most of the intracranial epidermoid cysts are benign, but malignant lesions are occasionally reported. These lesions appear as squamous cell carcinoma and carry a dismal prognosis. Here, we report a case of a primary intracranial squamous cell carcinoma arising in a cerebellopontine epidermoid cyst. The relevant literatures were also reviewed.

PATIENT CONCERNS

A 53-year-old woman presented with dizziness and diplopia 9 months in duration. Magnetic resonance imaging revealed an epidermoid cyst in the left cerebellopontine angle and prepontine region with a focal enhancing lesion on T1-weighted gadolinium-enhanced images.

DIAGNOSES

Histopathologic diagnosis revealed squamous cell carcinoma on a background of epidermoid cyst. Imaging studies excluded metastases.

INTERVENTIONS

The tumor was removed subtotally through a lateral suboccipital approach. The patient received intensity modulated radiation therapy (6720 cGy total) postoperatively.

OUTCOMES

The patient was free from recurrence of the tumor until 3 years after surgery, at which point she was lost to follow-up. The patient died 4 years after the surgery.

LESSONS

The epidermoid cyst may occasionally become malignant. Finding an area of enhancement through preoperative magnetic resonance imaging can help to make a correct diagnosis. Based on the review of previous reports, surgical removal followed by radiotherapy shows the best result to treat malignant epidermoid cysts.

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.

Survival outcomes for radiotherapy treatment of epidermoid tumors with malignant transformation

Epidermoid tumors are intracranial lesions that may occasionally undergo malignant transformation. Although surgical resection is the first-line treatment for malignant epidermoids, postoperative radiotherapy has been intermittently reported with favorable findings. Our analysis identified all previously reported patients with malignant epidermoids treated with surgical resection alone or surgery plus radiotherapy to examine the potential role for this adjuvant therapy. Whereas patients treated with surgery only had an overall survival of 6.6 months, those treated with postoperative radiotherapy demonstrated a statistically significant increase in survival to 12.7 months (log-rank test, p<0.003). Furthermore, the mean dosage of radiation given to this patient population was 52.2 Gy, with no appreciable survival benefit for the utilization of levels of radiation greater than 50 Gy. When determining the management for malignant transformation of epidermoid tumors, the combination of surgical resection and radiotherapy may be associated with improved short-term survival.

Epidermoid tumour of the lateral ventricle

Epidermoids occurring within the lateral ventricles are rare. At one time, they were regarded as anatomical curiosities. The lesions are of developmental aetiology, due to migration of epiblast inclusion at the time of formation of the cerebral vesicle. They are slow growing, and presentation is non-specific in the form of deteriorating mental functions. Generally seen in the fifth decade, but they have also been observed in the paediatric age group. MRI is suggestive of a cystic lesion, and is confirmed to be a typical epidermoid within the lateral ventricle at operation, often having a connection to the midline through the choroidal fissure. The cysts should be excised with no additional morbidity. Histopathology reveals typical stratified squamous epithelium.

Malignant transformation of intra-cranial epithelial cysts: systematic article review

INTRODUCTION

Epidermoid and dermoid cysts are among the most benign intra cranial tumors. Their malignant transformation into squamous cell carcinoma is rare. The authors reviewed the literature.

MATERIALS AND METHODS

MEDLINE and SCIENCE DIRECT searches, and examination of the references in the selected articles yielded 74 patients, 52 of whom fulfilled Garcia's criteria and were selected for the study. Survival analyses were performed to determine whether survival differences were of statistical significance, and P < 0.05 was considered as significant.

RESULTS

Malignant transformation is characterized by a rapid onset of symptoms, recurrence, leptomeningeal carcinomatosis (LC), and tumor enhancement at Computed Tomography Scan or Magnetic Resonance Imaging (87.8 showed this radiological feature). In this review, the SCCs were classified in five groups: (1) Initial malignant transformation of a benign cyst; (2) malignant transformation from a remnant cyst; (3) malignant transformation of a dermoid and epithelial cyst; (4) malignant transformation with leptomeningeal carcinomatosis; (5) other malignancies arising from benign cysts. The median survival was 9 months. Statistics show that LC was of poor prognosis and radiotherapy, although not statistically significant, seems effective against such lesions, with a median survival of 26 months as opposed to 3 months (P=0.077).

CONCLUSION

Although rare, malignant transformation of intracranial epithelial cysts has a poor prognosis and surgery followed by radiotherapy seems to be the best therapeutic modality.

Primary squamous cell carcinoma of the brain. A rare autopsy case

In the present study, a rare autopsy case of primary squamous cell carcinoma of the brain is described. The patient was a 49-year-old man who showed brainstem symptoms and signs. These included oculomotor, abducens and facial palsies, dysphagia, dysarthria, and long tract signs such as quadriplegia with Babinski's signs during the 3-year and 6-month course of his illness. Neuropathologically, poorly differentiated squamous cell carcinoma was seen in the pons, medulla oblongata, part of the midbrain and spinal cord, the base of the cerebellum, the hypothalamus, the optic chiasm, and the left parahippocampal gyrus. The base of the pons and medulla oblongata were extensively destroyed by tumor cells. The relevant literature regarding primary squamous cell carcinomas of the brain was reviewed, and the characteristic features of this rare condition were discussed.

Intracerebral epidermoid tumor: a case report and review of the literature

BACKGROUND

Intracerebral epidermoid cysts are rare lesions and may account for only 1.5% of intracranial epidermoid tumors. Cell entrapment from the mesectodermal origin of the neural crest within the primitive cerebral hemisphere may lead to the formation of such rare intracerebral lesions.

METHODS

An intracerebral epidermoid cyst located in the right temporal lobe that was surgically treated is presented. The origin, clinical course, radiological features, and surgical treatment of such uncommon lesions are discussed based on a review of the literature.

RESULTS

Intraoperative findings revealed an epidermoid tumor. The postoperative course was uneventful and the patient was discharged with no neurological deficits. On long-term follow-up (2 years), there were no signs of recurrence.

CONCLUSIONS

Truly intracerebral epidermoid tumors are rarely found. Cells originating from mesectodermal lines may migrate and remain trapped within the primitive cerebral hemisphere while the neural tube is closing, leading to the formation of such intraparenchymal epidermoid tumors. Accurate preoperative diagnosis can be very difficult due to the radiological similarities to other common intracerebral cysts (e.g., astrocytomas or gliomas). Magnetic resonance imaging (MRI) studies, especially with diffusion-weighted images, allow greater accuracy in the preoperative differential diagnosis. Radical surgical removal should be attempted, but a less aggressive surgical strategy should be considered if there is strong adherence between the tumor capsule and the brain tissue, particularly in eloquent areas.

Squamous cell carcinoma arising in an intracranial dermoid cyst--case report

A 47-year-old male presented with headache. Magnetic resonance imaging revealed an enhanced mass lesion in the cerebellar vermis and left cerebellar hemisphere and in the cisterna magna. Gross total removal of the tumor was performed. Histological examination demonstrated squamous cell carcinoma in the dermoid cyst. The patient subsequently received localized radiation therapy of total 55 Gy. He has been without tumor recurrence for 6 years since the surgery. We recommend local radiation therapy over 50 Gy following surgery.