Correlation of radiological features of white epidermoid cysts with histopathological findings

Cerebellopontine angle epidermoid cyst masquerading as trigeminal neuralgia: A rare presentation and surgical outcome

Cerebellopontine (CP) angle epidermoid cysts are rare, benign, slow-growing intracranial lesions that arise from ectodermal inclusions during embryogenesis. They often present with symptoms caused by compression of adjacent structures, with trigeminal neuralgia being an uncommon presentation. A 19-year-old female presented with a 1-month history of tingling sensation on the right side of her face. MRI of the brain revealed an extra-axial cystic lesion at the right CP angle extending into the ambient cistern. The lesion appeared hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging, and dirty hyperintense on FLAIR, with diffusion restriction on DWI and no blooming on SWI. It caused a mass effect with compression of the right pons and trigeminal nerve. The patient underwent microsurgical resection of the cyst, and histopathological findings confirmed the diagnosis of an epidermoid cyst. Postoperatively, the patient showed symptomatic improvement and was advised long-term follow-up. This case emphasizes the importance of advanced imaging in diagnosing rare intracranial lesions and highlights surgical resection as an effective treatment for CP angle epidermoid cysts presenting with atypical symptoms.

White epidermoid cyst of brainstem

White epidermoid cysts are rare intra-cranial lesions with an intrinsic brainstem location, though still rare. The location of the tumour poses radiological confusion and a therapeutic dilemma. Neuroimaging techniques like MRI with diffusion tensor imaging (DTI) in this case proved a useful tool in ruling out other pathologies at this location with certain morphologic similarities. MRI findings indicated a bilobed intra-axial lesion with heterogenous signal intensities on T1 and T2 weighted images. DTI showed splaying of cortico-spinal tracts. The intraoperative cystic nature of the lesion was established, followed by a biopsy report confirming the lesion to be a white epidermoid cyst.

Extra-dural epidermoid cyst of the parasellar region: A rare case report

INTRODUCTION

Intracranial epidermoid cysts (IECs) comprise less than 1 % of intracranial tumors. IECs begin forming at birth and slowly grows in size. Cerebellopontine angle is the most common location reported. Brain magnetic resonance imaging (MRI) plays crucial role in diagnosis. Gross total resection is the ideal management but adhesion to adjacent structures is often challenging.

CASE PRESENTATION

We presented a case of 57-year-old female with vertigo and chronic abnormal sensation in her left side of the face. Brain MRI suggested an IEC located in the left parasellar region, which compressed the left trigeminal nerve. Resection was performed through a pterional approach. Gross total resection was successful without injuring nearby structures. Histopathological examination confirmed the diagnosis of epidermoid cyst. Post-operative care was uneventful and patient was discharged 3 days after surgery.

DISCUSSION

Less commonly located IEC in the parasellar region, instead of the cerebellopontine angle, results in compression of the trigeminal nerve. Surgery is appropriate for symptomatic cases. Surgical resection through a pterional approach provided access to the deeply located lesion in the parasellar region. Gross total resection should always be attempted while considering the risk of injuring nearby structures.

CONCLUSION

Despite IECs being rare intracranial lesions with frequent adhesion and high rate of recurrence, gross total resection should always be attempted. Pterional approach provided great access for intracranial mass located in the parasellar region. Longer follow-up is suggested to monitor clinical outcome and also recurrence.

Fat in the brain: Facts and features

The presence of fat within a lesion in the brain is not only easy to identify on both CT/MRI but also can help narrow the differential. The purpose of this paper is to illustrate the spectrum of common and rare fat-containing lesions in the brain that are encountered in clinical practice. This paper intends to discuss 15 such lesions which are confirmed by MRI findings and histopathological correlation. We divided the spectrum of fat-containing lesions into lesions with adipose cells, lesions with cholesterol-rich content and tumours with lipomatous differentiation/transformation. Knowledge of these common and rare fat-containing lesions is essential for making the right diagnosis or narrowing the differential diagnosis.

Epidermoid cyst in the anus: A case report of an unusual location

INTRODUCTION AND IMPORTANCE

Epidermoid cysts are generally seen as benign skin conditions characterized by the formation of nodules that are enclosed and located just beneath the epidermal layer.

CASE PRESENTATION

This report presents the case of a 32-years-old woman with a mass that has been progressively growing for 11 years, situated at the right anal verge. The mass, which was asymptomatic throughout its development, was confirmed to be an epidermoid cyst.

CLINICAL DISCUSSION

Epidermoid cysts commonly present without clinical symptoms. Ultrasound is increasingly being employed for the initial assessment. However, CT and MRI scans provide more detailed and specific imaging features. Histopathological analysis can aid in the identification of an epidermoid cyst. Treatment is often unnecessary for epidermoid cysts that are small and uncomplicated; however, if intervention is required, a complete surgical removal with an intact cyst wall is typically the straightforward solution.

CONCLUSION

Epidermoid cysts are common and can manifest in various locations. When encountering a soft, well-defined mass in an atypical site for epidermoid cysts, it should be included in the differential diagnosis.

Spontaneous regression of an epidermoid cyst in a pediatric patient-Case report and review of the literature

Epidermoid cysts are infrequent, benign, slow-growing, space-occupying lesions that account for 0.5-1.8% of primary intracranial tumors. We report the case of a 17-month-old child who presented in 2015 for one episode of pallor associated with hypotonia. Epilepsy was excluded and MRI was recommended. The MRI was performed and there were no focal parenchymal lesions, but it showed an extra-axial ovoid lesion with imaging characteristics consistent with epidermoid cyst. Follow-up MRI at one year was performed and it showed minimal increased in dimensions of the cyst, without changes into the signal of the lesion. Another MRI was performed 7 years after and it showed complete resolution of the cyst. Six months afterwards, another MRI was performed and it confirmed the complete regression of the cyst, without any extra-axial masses reported. The patient did not present any neurological anomalies. No follow-up MRI was recommended afterwards. Spontaneous regression of epidermoid cyst in pediatric population is an extremely rare event, but it should be taken into account when the patient shows no symptoms. This is the third case of spontaneous regression of an epidermoid cyst reported in pediatric patients, and the first one in the temporal region. Careful follow-up and watchful waiting could be an option to surgical treatment in epidermoid cysts.

Intracranial Epidermoid Cyst: A Volumetric Study of a Surgically Challenging Benign Lesion

BACKGROUND

Intracranial epidermoid cysts are rare, benign tumors. Nevertheless, the microsurgical removal of these cysts is challenging. This is due to their capacity to adhere to the neurovascular tissue, as well as the associated difficulties in microsurgically peeling off their capsular wall hidden in dead angles. To better understand the rate of recurrence after surgical intervention, we have performed preoperative and postoperative volumetric analysis of epidermoid cysts, allowing the estimation of their growth rate after resection.

METHODS

Imaging data from 22 patients diagnosed and surgically treated for an intracranial epidermoid cyst between 2000 and 2022 were retrospectively collected from 2 European neurosurgical centers with microsurgical expertise. Volumetric analysis was performed on magnetic resonance imaging data.

RESULTS

Average cyst volume at diagnosis, before any surgery, measured in 12 patients was 28,877.6 ± 10,250.4 mm3 (standard error of the mean [SEM]). Estimated growth rate of incompletely resected epidermoids after surgery was 1,630.05 mm3 ± 729.95 (SEM). Assuming linear growth dynamics and normalizing to postoperative residual volume, the average postoperative growth rate corresponded to 61.5% ± 34.3% (SEM) of the postoperative residual volume per year. We observed signs of recurrence during a radiologic follow-up period of 6.0 ± 2.8 years (standard deviation) in more than 50% of our patients.

CONCLUSIONS

Due to their slow-growing nature, epidermoid cysts can often reach a complex multicompartmental size before resection, even in young patients, thus requiring complex approaches with challenging capsular resection, which implies a high risk of nerve and vascular injury per se. Tumor recurrence may be predicted on the basis of postoperative volumetry.

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.

Intracranial progression of the epidermoid cyst to a white epidermoid cyst in a pediatric patient: a case report

BACKGROUND

Epidermoid cysts are rare benign lesions that originate from remnants of ectodermal epithelial tissue, particularly infrequent in the pediatric population. They exhibit characteristic imaging features, with occasional variations leading to the development of a "white" epidermoid cyst. This transformation results from the presence of protein and lipid material within the cyst, causing intrinsic hyperintensity in T1-weighted images, signal hypointensity in T2-weighted images, and a bright signal in diffusion-weighted imaging.

CASE PRESENTATION

We describe the case of a 5-year-old Latina pediatric patient initially diagnosed with a typical epidermoid cyst. After 13 years of follow-up, this typical epidermoid cyst underwent a transformation, becoming a "white" epidermoid cyst.

CONCLUSIONS

Epidermoid cysts are rare intracranial lesions. The term "white epidermoid cyst" does not denote a variant; it represents a distinct transformation within an epidermoid cyst due to liquid and protein accumulation. This transformation should be considered in cases with specific imaging characteristics.

White epidermoid cyst transformation after stereotactic radiosurgery: illustrative case

BACKGROUND

White epidermoid cysts (WECs) are a rare type of epidermoid cyst with atypical radiological features. The epidemiological aspects and mechanisms of their onset remain unknown. Herein, the authors report a unique case of WEC transformation from a typical epidermoid cyst after stereotactic radiosurgery (SRS), confirmed by radiological and pathological findings.

OBSERVATIONS

The case involved a 78-year-old man with a history of 2 surgeries for a left cerebellopontine angle typical epidermoid cyst 23 years earlier and SRS using the CyberKnife for recurrent trigeminal neuralgia (TN) 14 years earlier. The tumor with high intensity on T1-weighted imaging, low intensity on T2-weighted imaging, without restriction on diffusion-weighted imaging had gradually enlarged after SRS. Therefore, a salvage surgery was performed via a left suboccipital craniotomy, and the intraoperative findings showed a cyst with a brown, viscous liquid component, consistent with those of WECs. Histopathologically, keratin calcification and hemorrhage were identified, leading to a diagnosis of WEC. The postoperative course was uneventful, and the TN resolved. No tumor recurrence was recorded at 2 years postoperatively.

LESSONS

To the best of the authors' knowledge, this is the first world case of WEC transformation from a typical epidermoid cyst after SRS, confirmed by radiological and pathological findings. Radiation effects could have been involved in this transformation.

Clinicopathological report on epidermoid cysts of the brain: A case series and literature review from an African perspective

INTRODUCTION

Epidermoid cysts are rare benign lesions of the central nervous system which accounts for approximately 1-2 % of all intracranial tumours. They are commonly located in the parasellar region, cerebellopontine angle; however, brain parenchyma origin is rare. We report clinicopathological features of these rare lesions.

METHOD AND MATERIAL

This is a retrospective study of epidermoid cyst of the brain diagnosed between 01 January 2014 and 31 December 2020.

RESULTS

The four patients had mean age of 30,8 years (range: 3-63), one male and 3 females. All four patients presented with headache and one associated with seizures. Radiological images showed two posterior fossa; each occipital and temporal locations. All tumours were successfully removed and histopathological assessment confirmed epidermoid cysts. All patients showed clinical improvement and were discharged home.

CONCLUSION

Epidermoid cysts of the brain are rare and still remain a preoperative clinico-radiological conundrum as they may be indistinguishable from other intracranial tumours. Therefore, collaboration with histopathologists is advised in the management of these cases.

Parasellar epidermoid cyst with unique radiological features: A case report and review of the literature

Intracranial epidermoid cysts (ECs) are encapsulated lesions lined by squamous cell epithelium and the most location is the cerebellopontine angle and appears with cerebrospinal fluid-like irregular mass. Occasionally, ECs present as high-density masses on computed tomography and atypical features in magnetic resonance images in the unusual area, which makes the diagnosis difficult. Here, we report a case of a female subject who complained of episodic left facial convulsions for more than 3 months. Computed tomography plain scan revealed a large hyperdense parasellar mass with atypical magnetic resonance findings. In this report, we analyzed retrospectively the radiological characteristics and histopathology of the parasellar EC, thus increasing awareness about this unusual image features.

Incidental findings on brain magnetic resonance imaging (MRI) in adults: a review of imaging spectrum, clinical significance, and management

Utilization of brain MRI has dramatically increased in recent decades due to rapid advancement in imaging technology and improving accessibility. As a result, radiologists increasingly encounter findings incidentally discovered on brain MRIs which are performed for unrelated indications. Some of these findings are clinically significant, necessitating further investigation or treatment and resulting in increased costs to healthcare systems as well as increased patient anxiety. Moreover, management of these incidental findings poses a significant challenge for referring physicians. Therefore, it is important for interpreting radiologists to know the prevalence, clinical consequences, and appropriate management of these findings. There is a wide spectrum of incidental findings on brain MRI such as asymptomatic brain infarct, age-related white matter changes, microhemorrhages, intracranial tumors, intracranial cystic lesions, and anatomic variants. This article provides a narrative review of important incidental findings encountered on brain MRI in adults with a focus on prevalence, clinical implications, and recommendations on management of these findings based on current available data.

Neurosurgical Management of Skull Base Epidermoid Tumors in Children

Epidermoid tumors (ET) are congenital and benign tumors that develop from de ectoderm during neurogenesis. In the skull base, these lesions can insinuate themselves into several intracranial compartments by filling the subarachnoid space, and possibly affecting some important structures, like the brainstem, cerebellopontine angle, the pituitary in the middle fossa, and others. In the pediatrics skull base tumors, the ET represents 7-9%, being very rare. The surgical perspective of these cases is dependent on the extension of the resection. We presented two cases of total and near-total resection of ETs in the pediatric skull base, with successful outcomes.

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.