Malignant transformation eight years after removal of a benign epidermoid cyst: a case report

The imaging dynamic changes in the malignant transformation of an epidermoid cyst: a case report and literature review

Malignant transformation of epidermoid cysts is a rare complication. Most of the previously reported cases have involved postoperative malignant transformations. We present a case of malignant transformation of a nonpostoperative epidermoid tumor into squamous cell carcinoma (SCC) that occurred in a 61-year-old Chinese woman. The patient's initial cranial MRI scan showed an epidermoid cyst with marginal enhancement in the pre-pontine cistern, and the lesion gradually enlarged after 10 months. A craniotomy was performed using to remove part of the tumor via the right retrosigmoid approach, and postoperative pathology confirmed that the transformation of the epidermoid cyst was malignant. Our case study suggests that the possibility of malignant transformation of epidermoid cyst should not be ignored on the basis of enhanced imaging features, regardless of whether they are nodular, annular, or patchy, as is the case for inflammation. Strict follow-up is required for early detection of malignant transformation to prompt correspondingly early clinical treatment.

Concurrent occurrence of squamous cell carcinoma in a cerebellopontine angle epidermoid cyst: A case report and review of the literature

Background:

Intracranial epidermoid cysts are rare benign lesions. Cases of malignant transformation (MT) into squamous cell carcinoma (SCC) have rarely been reported. We present a case of concurrent occurrence of SCC diagnosed during primary resection of epidermoid cyst (EC) and a relevant literature review.

Case Description:

A 61-year-old patient was diagnosed with a right cerebellopontine angle (CPA) lesion after suffering from vertigo, diplopia, and right trigeminal (V2) hypoesthesia. Brain magnetic resonance imaging (MRI) showed a lesion consistent with an EC, demonstrating restricted diffusion with rim-enhancing area on the medial side of the cyst. During resection, two different tissue pathologies were observed, one consistent with an epidermoid (which was completely removed) and an additional firm tissue adherent to the brainstem, preventing gross total resection. Pathological evaluation confirmed two separate histologies – epidermoid and SCC. The patient never recurred to complete the recommended radiotherapy. Eleven months following surgical resection, a follow-up MRI showed local massive recurrence of the enhancing lesion. He was, further, treated with radiotherapy and is currently being followed up.

Conclusion:

MT of an intracranial EC to SCC is rare and associated with poor prognosis. SCC may be found incidentally at time of primary resection or arise from a remnant of previously operated EC. Thus, aggressive complete resection should be intended, and separate pathological specimens should be sent from any abnormal region of the tumor.

Malignant transformation of a cerebral dermoid cyst into a squamous cell carcinoma with malignant intraperitoneal spreading along a ventriculoperitoneal shunt: illustrative case

BACKGROUND

Malignant progression of intracranial dermoid cysts into squamous cell carcinoma is extremely rare with only three reports published so far. Intracranial dermoid cysts are uncommon benign tumors lined by stratified squamous epithelium of embryonic ectodermal origin.

OBSERVATIONS

Here, the authors present the case of a 64-year-old female with a recurrent temporal dermoid cyst. After surgery for the recurrent dermoid cyst, once in the early 1990s and another 16 years later, the patient presented with headache and nausea due to hydrocephalus. After implantation of a ventriculoperitoneal shunt, she deteriorated rapidly and died only 60 days after admission. Autopsy revealed malignant transformation of the epithelial lining of the dermoid cyst into a squamous cell carcinoma resulting in neoplastic meningiosis and intraperitoneal tumor spread along a previously implanted ventriculoperitoneal shunt.

LESSONS

Malignant transformation should be considered in patients with dermoid cyst who show new leptomeningeal contrast enhancement. In the case of hydrocephalus, alternatives to peritoneal shunting should be considered.

Malignant Transformation of Recurrent Residual Cerebellopontine Angle Epidermoid Tumor: Significance of Clinical Vigilance and Long-term Surveillance

Epidermoid tumors (ET) are slow-growing masses where malignant transformations occur extremely rarely. Malignant transformation warning signs are the rapid-onset, progression, and recurrence of symptoms. The radiologic evidence for malignant transformation is contrast enhancement with rapid growth, observed with magnetic resonance imaging (MRI) or computed tomography scans. Here, we provide a case report of a 68-year-old woman with a long-standing history of left-sided cerebellopontine angle ET who presented with a recent worsening of symptoms, and MRI observation of new ET contrast enhancement. Surgical re-exploration and histopathologic confirmation are mandatory in this setting of recent symptom worsening and MRI observation of rapid mass growth.

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.

CT cisternography to visualize epidermoid tumors for stereotactic radiosurgery treatment planning

The visualization of intracranial epidermoid tumors is often limited by difficulties associated with distinguishing the tumor from the surrounding cerebrospinal fluid using traditional computed tomography (CT) or magnetic resonance imaging (MRI) modalities. This report describes our experience using CT cisternography to visualize intracranial epidermoid tumors in three illustrative cases. CT cisternography of the epidermoid tumor provides more clarity and precision compared to traditional neuroimaging modalities. We demonstrate the feasibility of using CT cisternography to produce high-resolution images with well-defined tumor margins that can be used effectively for precise SRS treatment planning.

Spontaneous Regression of Radiologically Diagnosed Epidermoid Cyst Originating from the Cerebellopontine Angle

BACKGROUND

Generally, asymptomatic epidermoid cysts (ECs) or ECs with minor symptoms controlled by medication are not treated further. Although epidermoid carcinomas are only sporadically reported, the possibility of malignant transformation of ECs is of concern.

CASE DESCRIPTION

A 77-year-old man under observation for a left cerebellopontine angle tumor presented with no symptoms, including headache, dizziness, or other cranial nerve abnormalities typical of cerebellopontine angle tumors. The tumor manifested as an extra-axial mass in the left cerebellopontine angle and measured 24 × 16 mm (length × width) on magnetic resonance imaging (MRI). As he was asymptomatic, his primary physician did not pursue invasive treatment but ordered follow-up MRI every 2 years. The tumor decreased in size 2 years after the initial MRI, and no tumor fragmentation was observed on the patient's spinal MRI. Ultimately, the tumor shrank to 19 × 11 mm over 22 years.

CONCLUSIONS

The reduction of an EC is extremely rare. We report a case of spontaneous regression of an EC and consider similar previous cases.

Cerebellar Squamous Cell Carcinoma Due to Malignant Transformation of Cerebellopontine Angle Epidermoid Cyst, Report an Interesting Case and Review the Literature

Malignant transformation of an epidermoid tumour is a rare entity that in almost all patients occurs at the same site of the primary lesion. We report a case of an epidermoid tumour with malignant transformation to squamous cell carcinoma (SCC) at the adjacent site but without any relation to the primary site of the tumour. A 30-year-old patient with a history of cranial surgery and resection of cerebellopontine (CP) angle epidermoid cyst five years ago, presented with a headache, nausea, and vomiting. Physical examination showed no neurological deficit. The brain magnetic resonance imaging (MRI) demonstrated a well-defined lesion within left middle cerebellar peduncle with no relation to CP angle cistern (the previous tumour site). It was isointense on T1, isointense on T2 and had a rim enhancement on gadolinium (GD) injection. Via retrosigmoid and transcortical approach, total resection of the tumour was performed. During the surgery, there was no visible relationship between the current lesion and the previously resected lesion site. Histopathology revealed squamous cell carcinoma. The systemic survey to finding a probable origin of the tumour was negative and the patient referred for performing brain radiotherapy. We are reporting a case of malignant transformation of epidermoid cyst separate from primary location. Moreover, malignant transformation can occur years after index surgery even after gross total resection.

A Rare Transformation of Epidermoid Cyst into Squamous Cell Carcinoma: A Case Report with Literature Review

BACKGROUND Epidermoid cysts are the most common benign skin lesions that can occur anywhere on the body, and frequently occur on the face, scalp, neck, and trunk. Typically, patients are asymptomatic, and the lesions present as firm skin-colored nodules filled with keratinous or sebaceous materials that are formed by cystic expansion of the epidermal epithelium. Malignant transformation is rare in epidermoid cysts. CASE REPORT This is a case report of a 77-year-old male Caucasian patient who presented with an epidermoid cyst on the left parietal area. Due to high suspicion, the cyst was surgically excised and sent to pathology which resulted in discovery of malignant squamous cell carcinoma with unclear margins. Aimed at obtaining clear margins, a wide excision was performed, which revealed clean margins and absence of residual cancerous cells. The patient recovered well without major complications. CONCLUSIONS Although the prevalence of epidermoid cysts is high, malignant transformation of epidermoid cysts into squamous cell carcinoma is rare. Due to its scarcity, the exact pathophysiology of malignant transformation is still poorly understood. The differential diagnosis should include the possibility of malignancy for highly suspicious lesions, and proper management guidelines should be established. Surgical resection should be the treatment of choice, and once removed, all surgically excised cysts should undergo pathologic evaluation. As clinicians, it is crucial to stay vigilant and have a low threshold for excision and thorough histological examination of specimens to allow early diagnosis and interventions which can significantly improve patient outcomes. Through the suggested guidelines, we hope to aid in better management and intervention in case of malignant transformation of epidermoid cysts.

Intracranial Squamous Cell Carcinoma Arising From a Cerebellopontine Angle Epidermoid Cyst Remnant Four Decades After Partial Resection

Intracranial epidermoid cysts are benign lesions that typically remain asymptomatic; however, although histopathologically benign, these cysts can rarely undergo malignant transformation into squamous cell carcinoma. Primary intracranial squamous cell carcinoma carries a poor prognosis as optimal treatment modalities remain unclear due to their low incidence. Here, we present a case of a cerebellopontine angle epidermoid cyst remnant that underwent malignant transformation into squamous cell carcinoma 40 years after partial resection. To our knowledge, this case establishes the longest time interval to date for an intracranial epidermoid cyst to undergo malignant transformation. We also review the relevant literature and discuss recent retrospective clinical studies that have analyzed the effect of multimodal treatment approaches on survival outcomes in patients with these lesions.

Proton beam therapy for malignant transformation of intracranial epidermoid cyst

We report the first clinical case on the successful use of proton beam therapy in the management of malignant transformation of intracranial epidermoid cyst. A 43-year-old man was initially diagnosed as this disease with left facial paresis, hypesthesia and hypoalgesia in the territories of the trigeminal nerve. After failure of surgical interventions, he was referred to our radiation centre. We performed a postoperative proton beam therapy for treatment. We delivered a total dose of 57 GyE in 31 fractions. He tolerated the treatment well with mild acute toxicities and remained healthy and functional by 2-year follow-up postradiotherapy. No evidence of delayed radiation-induced neurotoxicity was observed.

Microsurgical Treatment of Epidermoids. Case Report and Literature Review

The aim of the research: study the features of surgical treatment of epidermoids.

Materials and methods. We present a literature review and the clinical case of surgical treatment of a patient with epidermoid. We have searched medical databases: Medline, Russian Science Citation Index, EMedicine, United Medical Knowledge Base. We considered the features of the clinic, diagnosis, and surgical intervention. The article presents a clinical example of successful surgical treatment of a patient with an epidermoid cyst of the posterior cranial fossa. The result of the literature review was the writing of a clinical lecture; the current state of the issue of etiopathogenesis, diagnosis and management of patients with epidermoids was studied.

Results. The authors found that total microsurgical removal is the method of choice, and the operative technique should be aimed at preventing postoperative aseptic meningitis. Although it was not possible to establish the cause of the development of aseptic meningitis, the authors assume that the mechanism of its formation lies in the self-breaking of the capsule of the epidermoid cyst, probability of which was confirmed by a number of studies. Further study of this pathology is a promising direction in neurosurgery.

Conclusion. Difficulties in the diagnosis and choice of surgical tactics point at the need for detailed preoperative planning of surgical intervention, performing a precise total removal of a lesion with compliance with preventive measures for aseptic meningitis to improve clinical results and reduce the incidence of perioperative complications.

Repeated recurrent epidermoid cyst with atypical hyperplasia: A case report and literature review

RATIONALE

Epidermoid cysts are slow-growing, benign tumor which account for less than 1% of all intraspinal tumors and epidermoid cyst with Atypical Hyperplasia is very rare. Surgical resection is the standard treatment of the tumor, but recurrence is not uncommon after incomplete resection. Inappropriate treatment can lead to repeated recurrent. Here, we reported a case of repeated recurrent epidermoid cyst with atypical hyperplasia treated with radiotherapy after surgery.

PRESENTING CONCERNS

A 40-year-old female presenting with intraspinal epidermoid cyst showed incomplete paraplegia in lower limbs.

DIAGNOSIS

Back pain reappeared 19 months later after surgical treatment. The patient suffered marked weakness in both limbs, along with obvious muscle atrophy and sensation deficiency of warmth and pain in left lower limb. MRI demonstrated a cystic mass with solid content and peripheral strengthen in enhanced scan.

INTERVENTIONS

Extended excision with intraoperative local chemotherapy and postoperative radiotherapy was performed and a dramatic reversal of symptoms was gained 4 weeks after surgery, with a total dose of 46 Gy. Postoperative pathological examination revealed epidermoid cyst with mild to moderate atypical hyperplasia.

OUTCOMES

No acute side effects of the treatment were reported. Back pain obviously alleviated within 48 hours after surgery, while weakness and numbness of the lower limbs gradually improved and nearly disappeared in the 3-monthly follow-up visit. Until now, no recurrence is found during the 5-years follow-up.

LESSONS

Our study highlights that incomplete excision has led to repeated recurrent epidermoid cyst, but its complete removal with adjuvant radiotherapy has achieved remission of symptoms. Atypical hyperplasia discovered by pathological examination reminds us the possibility of malignant transformation and ensures the necessity of adequate treatment.

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.

Malignant Transformation of an Intracranial Extradural Epidermoid Cyst into Squamous Cell Carcinoma Presented with Cerebrospinal Fluid Leakage

We report a case of malignant transformation of an intracranial extradural epidermoid cyst into squamous cell carcinoma (SCC), that presented with cerebrospinal fluid (CSF) leakage at the time of recurrence. Intracranial epidermoid cysts are histologically benign and slow-growing neoplasms. They are congenital lesions that develop from ectodermal remnants during neuroembryogenesis. Malignant transformation of epidermoid cysts into SCC is very rare. Various clinical presentations of these tumors after malignant transformation are mentioned in the literature. None of the previous cases, presented with CSF leakage as the recent case did. In cases of malignant transformation, surgical resection and then adjuvant radiation therapy are highly recommended.

Primary Intracranial Epidermoid Carcinoma with Diffuse Leptomeningeal Carcinomatosis: Report of Two Cases

BACKGROUND

Malignant degeneration of epidermoid cyst (EC) with accompanying leptomeningeal carcinomatosis (LC) at presentation is extremely rare. We add two cases to the literature, including the first case of primary brainstem involvement with simultaneous diffuse LC, and discuss clinical and radiological cues to differentiate benign and malignant epidermoid tumors for early diagnosis.

CASE DESCRIPTION

The first patient in this report was a 54-year-old woman with recurrent aseptic meningitis and hydrocephalus. Imaging revealed a prepontine and parapontine extra-axial EC with an intra-axial brainstem ring-enhancing cystic lesion, diffuse leptomeningeal enhancement, and intradural extramedullary nodular deposits throughout the spine. Surgical decompression of the cysts confirmed the diagnosis of invasive primary squamous cell carcinoma of the brainstem and benign epidermoid tumor of the cerebellopontine cistern. The second patient was a 37-year-old woman with extensive left-sided cranial neuropathies. Imaging revealed prepontine and parapontine enhancing and nonenhancing deposits along multiple cranial nerves and diffuse leptomeningeal nodular enhancement in the thoracolumbar spine. A biopsy confirmed the diagnosis of infiltrative, poorly differentiated carcinoma adjacent to a benign EC. Both patients underwent systemic screening to rule out metastatic disease.

CONCLUSIONS

These cases illustrate that a high index of clinical suspicion is necessary for early diagnosis of disseminated disease in cases of recurrent episodes of aseptic meningitis. In cases of primary benign EC, aggressive resection should be attempted to reduce the risk of malignant degeneration. A separate biopsy specimen from the enhancing portion of the tumor is used to rule out an underlying coexisting malignancy. Multimodal management carries the best prognosis for primary intracranial squamous cell carcinoma with LC.

Surgical strategy for intracranial dermoid and epidermoid tumors: An experience with 33 Patients

Background:

The aim of this paper is to report on our surgical strategy and technique and to identify the best management for intracranial dermoids and epidermoids tumors (IDETs).

Methods:

We retrospectively reviewed 33 consecutive patients (14 males and 19 females; mean age at surgery, 37.9 years) with pathologically confirmed IDETs who underwent surgical resection, with mean follow-up of 7.2 years.

Results:

Gross total tumor removal was achieved in 24 cases (72.7%) with zero surgical mortality and a recurrence rate of 9%.

Conclusions:

The surgical strategies used in this group of patients enabled total removal of most tumors without surgical mortality and with low morbidity and recurrence rates, proving to be safe and effective.

Intracranial germinoma in the pineal region arising after subtotal resection of epidermoid cyst: case report

We present an unusual case of a germinoma of the pineal region arising adjacent to an epidermoid cyst in a 16-year-old male. Initial imaging findings were classic for epidermoid cyst. The patient underwent two partial resections at an outside institution, each specimen demonstrating pure epidermoid cyst. Follow-up imaging over a period of 24 months showed an area of progressive contrast enhancement adjacent to the initial lesion, suggesting the development of a neoplasm. Given the area of contrast enhancement in addition to worsening headaches and visual changes, he underwent a third and final resection at our institution. Pathology revealed a mixed germ cell tumor with prominent germinoma component in addition to a well-differentiated epidermoid cyst. Details of his imaging and pathologic findings are presented, and possible explanations for these findings are explored, the most likely of which is lack of complete resection at the onset failed to identify the whole of the neoplasm. We conclude that pediatric epidermoid cysts of the pineal region should always receive close follow-up, particularly when total resection is not performed.

Surgery and outcomes of six patients with intradural epidermoid cysts in the lumbar spine

Study design

This was a retrospective study.

Objective

The aim of this study was to analyze the clinical characteristics and discuss the treatment options for epidermoid cysts in the lumbar spine.

Summary of background data

Epidermoid cysts are rare benign neoplasms, which account for less than 1% of all intraspinal tumors. Due to their rarity, there are only a few case reports in the literature. Complete excision is the recommended treatment for an epidermoid cyst, but this is difficult to achieve in the spine. In spite of their benign nature, local recurrence is not uncommon for spinal epidermoid cysts after incomplete excision.

Methods

Six patients with an epidermoid cyst in the lumbar spine underwent surgical treatment in our center between 2004 and 2011. A total excision using microsurgical techniques and reconstruction was successfully undertaken in all patients. Clinical data and detailed pathologic results were retrospectively analyzed. All cases were followed up for a median time of more than 4 years. The clinical data and surgical efficacy were analyzed to suggest treatment options for epidermoid cysts in the lumbar spine on the basis of a literature review and our own experience.

Results

The mean age of the patients in this study was 37.7 years and the mean duration of pre-operative symptoms was 29.7 months (2 to 120 months). All patients were disease-free during their follow-up period. Radicular pain nearly disappeared, and patients suffering from neurologic deficits and defecation disorders recovered well.

Conclusions

Although an epidermoid cyst is a benign tumor, it is apt to recur locally following inadequate removal. Therefore, complete excision with preservation of neural function is an ideal protocol for intraspinal epidermoid cysts. Microsurgical techniques are very useful.

Malignant transformation of intracranial epidermoid cyst

Intracranial epidermoid cysts (ECs) are rare, histologically benign, slow-growing, congenital neoplasms of central nervous system that may arise from retained ectodermal implants. Malignant transformation of an EC to squamous-cell carcinoma is rare; only 13 cases have been reported. We present the case of a 42-year-old woman presenting with left hemiparesis 18 months after performing partial resection of an epidermoid cyst of right middle and posterior fossa, whose pathological report revealed to be a malignant transformation of previous epidermoid tumor. Additionally, we performed pertinent literature review.

Malignant transformation of an intramedullary epidermoid cyst in the thoracic region of the spinal cord

Malignant transformation of epidermoid cysts (ECs) to squamous cell carcinomas (SCCs) in the CNS is exceedingly rare and has only been described in intracranial ECs. In this article, the authors describe a 53-year-old man with a history of a previously resected T3–4 EC, who presented with a 2-month history of progressively worsening weakness in the left side of his body. Magnetic resonance imaging revealed an enhancing mass in the T3–4 region, the exact location of the previous cyst. The mass was resected in gross-total fashion, and pathological analysis revealed an SCC. Postoperatively, the patient regained full strength in his lower extremities. After the resection, he received radiotherapy administered at an isodose of 50 Gy. To the authors' knowledge, this is the first reported case of malignant transformation of an intramedullary spinal EC in the literature.

Primary intracranial basaloid squamous cell carcinoma: an enigma

Primary intracranial squamous cell carcinoma is extremely rare, with most cases arising from malignant transformation of dysembryogenetic lesions such as epidermoid and dermoid cysts. Intracranial squamous cell neoplasm arising de novo is even rarer and has been reported in only four patients to date. We herein describe a case of primary intracranial squamous cell carcinoma arising de novo in the right frontal lobe in a 35-year-old woman treated with a combination of surgery and postoperative conformal radiation. We have also shed light on the biology and the therapeutic options of this enigmatic tumour.

Complications of gamma knife neurosurgery and their appropriate management

There are four main risks with Gamma Knife neurosurgery. Firstly, there are direct complications that would not have arisen if the patient had not undergone the specific treatment under consideration. For radiosurgery, the direct complications are radiation-induced damage to the tissues, which may be temporary or permanent. They may be expressed clinically or be clinically silent. In addition, there are complications that are specific to certain diseases and their locations, such as pituitary failure following treatment of pituitary adenomas and deafness, facial palsy, or trigeminal deficit following the treatment of vestibular schwannomas. Second, there are indirect or management-related complications arising from delayed control of the disease process, such as a re-bleed after treatment of a vascular lesion before its occlusion. Third, there is the risk of induction of neoplasia from irradiation of normal tissue or tumor. These are separate processes. An example of the first would be induction of a glioma after treatment of a vascular malformation. An example of the second would be induction of malignant change in a benign vestibular schwannoma. Finally, there is treatment failure, where tumors continue to grow after treatment or vascular malformations fail to occlude.

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.

Malignant transformation of an epidermoid cyst in the cerebellopontine angle

Intracranial squamous cell carcinoma is extremely rare, with most of the cases arising from malignant transformation of an epidermoid or a dermoid cyst. The patient presented with facial weakness. Initial magnetic resonance imaging revealed a mass in the right cerebellopontine angle. A subtotal resection was performed via right retrosigmoid suboccipital approach. Histopathological findings were consistent with an epidermoid tumor. Five months later, the patient underwent gamma knife radiosurgery due to highly probable recurrent epidermoid tumor. Two years after, the patient's neurological deficit had been newly developed, and follow-up magnetic resonance imaging demonstrated a large contrast-enhancing tumor in the left cerebellopontine angle, which compressed the brainstem. After resection of the tumor, histopathological examinations revealed a squamous cell carcinoma probably arising from an underlying epidermoid cyst. We report a case of an epidermoid tumor in the cerebellopontine angle that transformed into a squamous cell carcinoma.

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.

Malignant transformation six months after removal of intracranial epidermoid cyst: a case report

Intracranial epidermoid cysts are uncommon benign tumors of developmental origin; malignant transformation of benign epidermoid cysts is rare, and their prognosis remains poor. We report a case of squamous cell carcinoma arising in the cerebellopontine angle. A 52-year-old man presented with left facial paralysis and cerebellar ataxia. He had undergone total removal of a benign epidermoid cyst six months previously. Postoperative magnetic resonance imaging of the brain revealed a heterogeneous and cystic lesion in the left cerebellopontine angle with hydrocephalus. The cyst wall was enhanced by gadolinium. He underwent ventricle-peritoneal shunt and removal again; the histopathological examination revealed a squamous cell carcinoma possibly arising from an underlying epidermoid cyst. This entity is being reported for its rarity. The presence of contrast enhancement at the site of an epidermoid cyst combined with an acute, progressive neurological deficit should alert the neurosurgeon to the possibility of a malignant transformation.

Malignant transformation 20 years after partial removal of intracranial epidermoid cyst--case report

A 74-year-old woman presented with malignant progression of remnant epidermoid cyst manifesting as sudden onset of right ptosis and double vision. She had right oculomotor nerve paresis. She had a history of surgery for right cerebellopontine angle epidermoid cyst 20 years previously. T(1)-weighted magnetic resonance (MR) imaging demonstrated a hypointense mass lesion in the right cerebellopontine angle and basal cistern, and an isointense mass in the right paraclinoid region which was strongly enhanced. Diffusion-weighted MR imaging showed hyperintense areas in the right cerebellopontine angle, ambient cistern, and basal cistern, and the paraclinoid mass as hypointense. Surgery was performed using Dolenc's approach. Histological examination revealed that the paraclinoid tumor adjacent to the epidermoid tumor remnant was malignant transformation of epidermoid cyst into squamous cell carcinoma. She was treated with 46 Gy linac radiotherapy. She has been without tumor recurrence for 17 months. Malignant change of epidermoid cyst is extremely rare, but rapid progress of the symptoms suggests malignant transformation. MR imaging with gadolinium is useful for diagnosis.

Primary intracranial squamous cell carcinoma in the brain stem with a cerebellopontine angle epidermoid cyst

Primary intracranial squamous cell carcinoma is extremely rare, with most cases arising from a preexisting benign epidermoid cyst. We report a rare case of primary intracranial squamous cell carcinoma in the brain stem with a cerebellopontine angle (CPA) epidermoid cyst. A 72-year-old female suffered from progressive left hemiparesis, difficulty in swallowing, and right hemifacial numbness. Diffusion-weighted magnetic resonance imaging revealed a high signal intensity (SI) lesion in the CPA region and an intra-axially ring-enhanced cystic mass in the right brain stem with low SI. Whole-body positron emission tomography showed no evidence of metastatic disease. The histological findings revealed a typical epidermoid cyst in the CPA region and a squamous cell carcinoma in the brain stem. We speculate that the squamous cell carcinoma may have been developed due to a chronic inflammatory response by the adjacent epidermoid cyst. The patient underwent a surgical resection and radiotherapy. After 12 months, she had no evidence of recurrence.

Squamous cell carcinoma arising from a presacral epidermoid cyst: CT and MR findings

We report CT and MRI findings in a case of squamous cell carcinoma arising from a presacral epidermoid cyst, which has not been previously reported. CT findings revealed a focal wall thickening of the anterior wall of the huge presacral cystic mass. The squamous cell carcinoma was more hypointense than the cystic fluid on T1- and T2-weighted images and showed heterogeneous enhancement on contrast enhanced T1-weighted image.

Primary intracranial squamous cell carcinoma arising in an epidermoid cyst—A case report and review of literature

Primary intracranial squamous cell carcinoma is extremely rare, with most of the cases arising from malignant transformation of an epidermoid or a dermoid cyst. We report here a case of a 45-year-old male patient who presented with 1-month history of intermittent headache and recent onset of altered sensorium. Imaging revealed a midline posterior fossa mass lesion compressing the fourth ventricle and causing hydrocephalus. A provisional diagnosis of dermoid cyst was considered. Histopathological examination revealed a squamous cell carcinoma possibly arising from an underlying epidermoid cyst. This entity is being reported for its rarity.

Imaging of cerebellopontine angle lesions: an update. Part 2: intra-axial lesions, skull base lesions that may invade the CPA region, and non-enhancing extra-axial lesions

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions responsible for cerebellopontine angle (CPA) syndrome. However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion- and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion's site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Non-enhancing extra-axial CPA masses are cystic (epidermoid cyst, arachnoid cyst, neurenteric cyst) or contain fat (dermoid cyst, lipoma). Tumours can also extend into the CPA by extension from the skull base (paraganglioma, chondromatous tumours, chordoma, cholesterol granuloma, endolymphatic sac tumour). Finally, brain stem or ventricular tumours can present with a significant exophytic component in the CPA that may be difficult to differentiate from an extra-axial lesion (lymphoma, hemangioblastoma, choroid plexus papilloma, ependymoma, glioma, medulloblastoma, dysembryoplastic neuroepithelial tumour).

MRI findings of malignant transformation of epidermoid cyst: case report

Malignant transformation of epidermoid cysts into squamous cell carcinoma (SCC) rarely occurs. A 67-year-old man initially presented with an 8-year history of right trigeminal neuralgia. His symptoms had changed into right facial anesthesia with right-ear hearing impairment 8 months before first consulting a neurosurgeon at our hospital. Results obtained using MRI suggested an epidermoid cyst in the right cerebellopontine angle, but showed atypical findings of a small enhancing nodule in the periphery and surrounding edema in the cerebellum and pons. Surgery was performed to remove the mass, but a small nodule was not reached. Despite stereotactic radiosurgery, the patient's clinical course deteriorated; he died 13 months after the first MRI examination. Autopsy revealed SCC originating from the epidermoid cyst. We present serial MRI and pathologic findings in the early and terminal phases of this patient.