Intracranial Epidermoid Cysts Research Articles

P.084 Early malignant transformation of intracranial epidermoid cysts: a case report and systematic review

Background: Intracranial epidermoid cysts (IEC) are benign congenital intracranial lesions that rarely undergo malignant transformation. We report a case of IEC evolving into squamous cell carcinoma (SCC) 1-year post-resection. Further, we conducted a systematic review on cases of early malignant transformations of IECs. Methods: MEDLINE, EMBASE, and Scopus were searched from inception until December 2023 for studies reporting malignant transformations of IECs within 2 years of diagnosis. Results: A 48-year-old female underwent surgical resection of a cerebellopontine angle (CPA) IEC in May 2022. She re-presented in July 2023 with headaches, nausea, vomiting, right facial weakness, and rapid cyst progression. Repeat surgical resection revealed a high-grade SCC. Our systematic review identified 19 (10 females, 9 males) additional IEC cases undergoing malignant transformation within 2 years. The mean age at presentation was 57.6 years, most common location was CPA (n=13, 68.4%) and mean time between IEC to malignant transformation was 10.6 months. Eighteen (94.7%) cases transformed to SCC, of which 2 had leptomeningeal carcinomatosis, and 1 transformed to glioblastoma. Conclusions: While malignant transformations of IECs are rare, regular postoperative follow-up is crucial for early malignancy detection and treatment initiation. Further study is warranted to evaluate factors contributing to accelerated malignant progression of IECs.

Pineal Gland Epidermoid cyst, a rare Tumor

Background: Intracranial epidermoid cysts, forming 1% of adult and 3-8% of pediatric brain tumors, are among the rarest of intracranial neoplasms. Originating from ectodermal remnants retained during embryonic development, pineal epidermoid cysts are rare benign tumors that often manifest as obstructive hydrocephalus due to midbrain tectum compression. Objective: To report on the clinical presentation, diagnostic process, and surgical management of a pineal epidermoid cyst in a young adult, emphasizing the role of ventriculoperitoneal shunting and the outcomes of surgical intervention. Methods: A case study of a 20-year-old male presenting with a 4-month history of occipital headaches and vertigo, without seizures, neurological deficits, or visual disturbances. Diagnostic evaluation included brain imaging that revealed hydrocephalus secondary to a pineal space-occupying lesion. A ventriculoperitoneal shunt was placed for obstructive hydrocephalus treatment prior to the surgical excision of the pineal lesion. Results: The patient underwent a ventriculoperitoneal shunting procedure, followed by a suboccipital transtentorial craniotomy 2 months later, leading to the complete resection of the pineal space-occupying lesion. The histopathological analysis confirmed the diagnosis of a pineal epidermoid cyst. Post-surgical follow-up indicated significant symptomatic improvement with no recurrence observed. Conclusion: Pineal epidermoid cysts, while rare, can significantly impact patient well-being through the development of obstructive hydrocephalus. Early intervention with ventriculoperitoneal shunting followed by surgical resection can lead to favorable outcomes. Long-term monitoring is essential to ensure there is no recurrence.

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

BackgroundIntracranial 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 neuro-vascular tissue as well as the associated difficulties in micro-surgically peeling off their capsular wall hidden in dead angles. To better understand the rate of recurrence after surgical intervention, we have performed pre- and postoperative volumetric analysis of epidermoid cysts allowing the estimation of their growth rate after resection. MethodsImaging data from 22 patients diagnosed and surgically treated for an intracranial epidermoid cyst between 2000 – 2022 was retrospectively collected from two European neurosurgical centers with microsurgical expertise. Volumetric analysis was performed on magnetic resonance imaging (MRI) data. ResultsAverage cyst volume at diagnosis, prior to any surgery, measured in 12 patients, was 28877.6 ± 10250.4 mm3 (SEM). Estimated growth rate of incompletely-resected epidermoids after surgery was 1630.05 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 radiological follow-up period of 6.0 ± 2.8 years (SD) in more than 50% of our patients. ConclusionsDue 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 based on postoperative volumetry.

Trigeminal neuralgia revealing an epidermoid cyst impinging on the Vth cranial nerve: A case report

Intracranial epidermoid cysts, also referred to as intracranial primary cholesteatomas, are uncommon, benign tumors characterized by slow, linear growth patterns akin to normal epidermal tissue. They typically become symptomatic around age 43, with a slight female predominance, and are most frequently located in the cerebellopontine angle. This summary presents the case of a 62-year-old woman suffering from paroxysmal excruciating pain of the right hemiface, indicative of trigeminal neuralgia, linked to an intracranial epidermoid cyst in the cerebellopontine angle. Radiological assessment, through magnetic resonance imaging, was instrumental in identifying the cyst. Total surgery resection is the most effective treatment, but it can be challenging due to tumor adherence to important neurovascular structures, therefore responsible for an incomplete removal of the proliferative capsule causing a higher risk of recurrence. The case also raises questions about treatment options, as the patient opted against surgical intervention. Managing intracranial epidermoid cysts requires a careful weighing of potential benefits against associated risks.

THU101 A Challenging Case Of Recurrent Suprasellar Epidermoid Cyst With Visual Field Deficits

Abstract Disclosure: S. Ahsun: None. A. Atri: None. R. Bhat: None. C. eaton: None. N. Blocher: None. A challenging case of recurrent suprasellar epidermoid cyst with visual field deficits. Introduction: Intracranial epidermoid cysts account for approximately 1% of all intracranial tumors. The most common location of occurrence is cerebellopontine angle. Suprasellar region is the second most common location. We present a case for suprasellar epidermoid cyst with visual field deficits. Case Presentation: A 52 y/o female presented to an ophthalmologist for blurring of vision and was found to have bitemporal hemianopia. MRI of the brain showed a large suprasellar mass of 6.9x4.2x3.3 cm with extension into the surrounding structures. A portion of the cyst wall was hemorrhagic. There was significant mass-effect on the optic chiasm and bilateral optic tracts. Patient underwent elective craniotomy with left frontotemporal approach. A characteristic pearly wide epidermoid capsule was visualized through the oculomotor triangle. The optic nerve was noted to be quite distorted in its course, exiting from the optic canal and being pushed superiorly by the epidermoid tumor. Accessible tumor capsule was resected, however due to the dense adhesions of the epidermoid cyst to the surrounding vasculature and the optic nerves, complete resection was not attempted. Postoperatively, patient developed right-sided hemiparesis due to an acute infarct. Patient also developed some dementia, hyperphagia and aggressive behavior following her surgery. She started her rehabilitation therapy but had persistent dementia and cognitive decline. Repeat vision testing showed right superior homonymous hemianopia. MRI of the brain a year after the initial surgery showed growth of the residual cyst and some obstructive hydrocephalus but without any symptoms. She underwent a second debulking procedure that was successful with complete excision of the residual tumor but the patient had delayed recovery. She subsequently underwent tracheostomy and PEG tube placement and was transferred to the rehabilitation facility. She is now awake but still nonverbal. Patient also developed panhypopituitarism and is currently on the replacement for cortisol and thyroid hormone. She is also on DDAVP for her diabetes insipidus which seems to be permanent in her case. Conclusion: This case highlights some important facts: 1. Epidermoid cysts are challenging from the management standpoint. Only 50-80% can be resected completely. Incomplete removal increases the chances for recurrence which are variable at 1-54%. 2. Even in cases of recurrent growth repeat surgery should only be performed if patient has significant symptoms from the tumor. 3.As per the literature patients with adjuvant radiotherapy have improved outcomes. As in our case radiotherapy should have been considered in the setting of recurrence of the tumor. 4.Endoscopic endonasal approach is a new modality that has shown a very low rate of complications after resection. Presentation: Thursday, June 15, 2023

Strangulation of the abducens nerve by an arachnoid band within an epidermoid cyst: illustrative case.

Intracranial epidermoid cysts (ECs) are rare benign lesions of ectodermal origin that can be found in the cerebellopontine angle (CPA). If large enough, they compress surrounding structures, causing cranial neuropathies, cerebellar dysfunction, and hydrocephalus. In this case report, the authors present a patient with headaches and diplopia secondary to a CPA EC. The cyst had wrapped itself around and was strangulating the abducens nerve. This choking of the nerve was believed to have been the cause of the patient's double vision. The arachnoid band was released with a myringotomy knife. Intracranial ECs typically cause symptoms from mass effect on surrounding structures; it is unusual for one to have choked off the nerve in the fashion presented in this case. Knowledge of the potential ways that ECs can affect nervous structures is critical for resecting them without injuring normal tissue.

Computerized Tomography Texture Analysis in the Differential Diagnosis of Intracranial Epidermoid and Arachnoid Cysts.

This study evaluated the differences between arachnoid and epidermoid cysts in computerized tomography (CT) texture analysis (TA). The study included 12 patients with intracranial epidermoid cysts and 26 patients with intracranial arachnoid cysts who were diagnosed with diffusion-weighted magnetic resonance imaging (DW-MRI) and who had undergone an unenhanced CT examination before treatment. The LIFEx application software was used to obtain texture features. Eighty-two texture features from 38 lesions were automatically calculated for each lesion. The Shapiro-Wilk test was used to test the normality of the scores, and the Mann-Whitney U Test was used to test the difference between the groups. Receiver operating characteristic (ROC) curves and multivariate logistic regression modeling examined the parameters' diagnostic performances. The median age of the patients was 53 years (range: 19-88 years). Eighty-two texture parameters were evaluated in the first order: gray-level co-occurrence matrix (GLCM), gray-level run length matrix (GLRLM), neighbor gray-tone difference matrix (NGTDM), and gray-level size zone matrix (GLSZM) groups. There was a statistically significant difference between the arachnoid cyst and the epidermoid cyst in the variables of compacity, compactness 1, compactness 2, sphericity, asphericity, sum average, coarseness, and low gray-level zone (p<0.05). According to the multiple logistic regression model, it was determined that the sum average in the GLCM group (B=-0.11; p=0.015), coarseness (B= 869.5; p=0.044) in the NGTDM group, and morphological sphericity (B=24.18; p=0.047) were the radiomics variables that increased the probability of epidermoid diagnosis. According to the classification table of the model, the sensitivity rate was found to be 83%, and the specificity rate was found to be 96%. Therefore, the probability of accurate model classification was 92%. CT TA is a method that can be applied with high diagnostic accuracy in the differential diagnosis of intracranial epidermoid and arachnoid cysts, especially in patients who cannot undergo an MRI examination.

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

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 25years after initial resection. Additionally, we performed a systematic review including 94 studies reporting intracranial EDC to SCC transformation. 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. The overall median time to transformation was 60months (95% confidence interval {CI}, 12-96). Transformation time was significantly shorter in the no surgery group (10months, 95% CI undefined) versus the other 2 groups (60months, 95% CI, 12-72 in surgery only and 70months, 95% CI, 9-180 in surgery+adjuvant therapy group, both P < 0.01). Overall survival was significantly longer in the surgery+adjuvant therapy group (13months, 95% CI, 9-24) versus the other 2 groups (3months, 95% CI, 1-7 in surgery only and 6months, 95% CI, 1-12 in the no surgery group, both P<0.01). We report a rare case of delayed malignant transformation of an intracranial EDC to SCC, occurring nearly 25years 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.

Rare Cortical and Intraparenchymal Epidermoid Cyst within the Right Occipital Lobe (P3-4.004)

<h3>Objective:</h3> N/A <h3>Background:</h3> The differential diagnosis for a diffusion-restricting cortical lesion on brain magnetic resonance imaging (MRI) is broad and includes acute ischemic stroke, abscess, demyelination, Creutzfeldt Jakob disease, encephalitis, and epidermoid cyst. <h3>Design/Methods:</h3> <h3>Case description:</h3> A 13-year-old boy with accelerated growth underwent MRI for pituitary assessment, which incidentally demonstrated a non-enhancing, T2 hyperintense right occipital lesion. No diffusion weighted imaging (DWI) sequences were obtained, and the lesion was suspected to represent encephalomalacia. Five years later, he developed left visual field difficulties and repeat MRI identified right occipital lesional growth with high DWI and low apparent diffusion coefficient (ADC) signal. The patient underwent resection of the right occipital lesion. Histopathology revealed keratin encapsulated by squamous epithelium, consistent with an epidermoid cyst. Our patient is currently doing well, and his left visual field vision is improved. <h3>Results:</h3> <h3>Discussion:</h3> Intracranial epidermoid cysts comprise 1% of primary intracranial tumors and are derived from ectodermal inclusions during neural tube closure. They usually present in middle age due to mass effect on adjacent structures. Epidermoid cysts most commonly occur at the cerebellopontine angle and parasellar region. A cortical location of an intracranial epidermoid cyst, as in our patient’s case, is very rare. The signal intensity of the epidermoid cyst on MRI is variable due to its composition of keratin and lipids and there is usually no associated edema. Total surgical excision is the mainstay of treatment for intracranial epidermoid cysts. Recurrence is not uncommon, but growth is usually slow over many years. <h3>Conclusions:</h3> Neurologists should include intraparenchymal epidermoid cysts in the differential diagnosis for a diffusion restricting lesion on MRI of the brain. <b>Disclosure:</b> Dr. Webb has nothing to disclose. The institution of Dr. Burns has received research support from NIH (NINDS, NCI), DOD, ABTA, Ivy foundation, insightec, Mayo Clinic, Abbvie, . Dr. Zhang has nothing to disclose. Dr. Sener has nothing to disclose.

A Case Report on the Elusivity of Imaging in Detecting a Ruptured Dermoid Cyst (P8-4.005)

<h3>Objective:</h3> We present a case report on the rare clinical entity of the ruptured intracranial dermoid cyst and the importance of imaging in confirming the diagnosis. <h3>Background:</h3> Intracranial epidermoid and dermoid cysts represent about 1% of intracranial tumors. They can contain lipid, cholesterol crystals, and other ectodermal derivatives. These cysts are considered to be benign tumors, however if they rupture they can cause a significant inflammatory reaction resulting in chemical meningitis with expected symptoms of headache, nuchal rigidity, seizure, hydrocephalus, or even death. We present a case of a ruptured dermoid cyst after a mechanical fall with head trauma in an elderly male with Parkinson’s disease. CT scan was non specific and showed scattered hypoattenuation within the left lateral ventricle with Hounsfield units possibly representing lipid content. MRI was obtained to better characterize interventricular material seen on CT and showed T1 hyperintensity compatible with fat signal within the ventricles and cerebrospinal fluid. This imaging allowed for definitive diagnosis of ruptured dermoid cyst. With this information, the clinical team monitored the patient closely for signs of chemical meningitis in the case that further intervention were needed. Fortunately, the patient did well and was discharged after three days of observation. <h3>Design/Methods:</h3> Not applicable <h3>Results:</h3> Not applicable <h3>Conclusions:</h3> MRI proves to be essential in confirming a diagnosis of ruptured dermoid cyst which can present nonspecifically on CT scan. Once the diagnosis is confirmed, patients must be monitored for chemical meningitis and subsequent sequelae. <b>Disclosure:</b> Dr. Singh has nothing to disclose. Dr. Albadareen has nothing to disclose.

Intracranial epidermoid cysts: benign entities with malignant behavior: experience with 36 cases

Intracranial epidermoid cysts are benign slow-growing ectodermal inclusions that account for less than 1% of all intracranial tumors. We retrospectively reviewed 36 such cases to evaluate the demographic characteristics, clinical manifestations, anatomical distribution, surgical management, and treatment outcome of these tumors. Additionally, we sought to identify the relationship between median or paramedian cistern tumor localization and clinical parameters, such as recurrence risk, hospitalization duration, and postoperative complication rates. The most frequently observed neurological symptoms were transient headaches (77.8%), dizziness (36.1%), CN VII palsy (19.4%), CN VIII hearing difficulty (19.4%) and cerebellar signs (19.4%). The most common surgical approaches included retrosigmoid (36.1%), subfrontal (19.4%) and telovelar (19.4%) approaches; gross total resection was feasible in 83.3% of cases. The postoperative complication rate was 38.9%. Tumors were more frequently found in the paramedian cisterns (47.2%), followed by the median line cisterns (41.6%). Multivariate analysis revealed that postoperative hydrocephalus and age < 40 years were prognostic factors for tumor recurrence. Median-like tumor location was a risk factor for the presence of symptomatic hydrocephalus both preoperatively and postoperatively, increasing the likelihood of protracted hospitalization (> 10 days). Despite their benign histopathological nature, these tumors have an important clinical resonance, with a high rate of postoperative complications and a degree of recurrence amplified by younger age and hydrocephalus.

Endoscopic endonasal transclival approach for a ventral brainstem epidermoid cyst: illustrative case.

Intracranial epidermoid cysts are benign, slow-growing malformations that most commonly arise at the skull base. Maximizing resection of the cyst contents and the capsule reduces long-term recurrence but can be made difficult by cyst wall adherence to critical neurovascular structures. Expanded endonasal approaches (EEAs) offer an alternative to traditional open transcranial approaches for accessible epidermoid cysts. In this case report, the authors demonstrate a transclival EEA for a large, ventral brainstem epidermoid cyst. A 41-year-old woman who presented with progressive headaches, diplopia, malaise, and fatigue was found to have a 4.7-cm midline, ventral brainstem epidermoid cyst. She underwent an expanded endonasal transclival approach that exposed the brainstem from the level of the dorsum sella to the tip of the basion. A near-total resection was completed with removal of all cyst contents and most of the capsular wall. Reconstruction was completed with Duragen, an autologous fat graft, and a nasoseptal flap. Postoperatively, she had a partial left cranial nerve VI palsy that remained stable 8 weeks after surgery. The expanded endoscopic transclival approach can facilitate effective resection of midline, ventral epidermoid cysts.

Epidermoid cyst in atypical intracranial areas transformed to epidermoid carcinoma: a case report

Intracranial epidermoid cysts, also known as epidermal cysts, grow slowly and may be occult. When small, epidermoid cysts are usually clinically unremarkable or cause no definitive symptoms. At typical sites, they are easily found through magnetic resonance imaging, which aids evaluation before surgery. However, in rare cases, epidermoid cysts are situated in unusual locations or transformed to malignancy, and preoperative misdiagnosis is possible. Here, the case of a 58-year-old male patient who presented with weakness in the left lower limb and was diagnosed with a malignant epidermoid cyst in the right frontoparietal lobe, right lateral ventricle, is reported. Surgery was performed to remove the tumour followed by radiotherapy, and the patient was reported to be living independently after approximately 11 months of follow-up.

Combined Endoscopic and Exoscopic Resection of Intracranial Epidermoid Cysts

This article aims to introduce an endoscopic-exoscopic technique for the resection of epidermoid cysts. We retrospectively analyzed the intracranial epidermoid cysts patients who received whole-course combined endoscopic and exoscopic resection between 2017 and 2020 at our institution, to explore the benefit of combined endoscopic and exoscopic resection of intracranial epidermoid cysts, and evaluated the clinical utility of the endoscopic-exoscopic technique. A total of 17 patients were enrolled in the study. Of all patients, 6 patients (35.3%) underwent total resection, 10 patients (58.8%) underwent subtotal resection, and 1 patient (5.9%) underwent partial resection. Postoperative surgical complications were seen in 3 patients (17.6%), including intracranial infection in 2 patients (11.8%), and a delayed postoperative hematoma was observed in the seventh day after operation for 1 patient (5.9%), who was treated in a conservative manner and recovered smoothly from the hemorrhage. The median follow-up time was 33.3 months (range: 14.5-54.5 months). During the follow-up period, there was no recurrence of the tumors that received total resection. Two patients developed residual tumor regrowth but did not show any symptoms, therefore no further surgery was required. Endoscopic-exoscopic technique is safe and efficient in the resection of intracranial epidermoid cysts with panoramic views and superior maneuverability. With further development and accumulation of practical experiences, the endoscopic-exoscopic technique can also be applied in the resection of other intracranial tumors.

Strategies for intraoperative management of the trigeminal nerve and long-term follow-up outcomes in patients with trigeminal neuralgia secondary to an intracranial epidermoid cyst.

BackgroundEpidermoid cysts (ECs) are one of the most common causes of secondary trigeminal neuralgia (TGN). However, most previous studies have primarily focused on whether complete tumor resection was achieved, and few studies have discussed the primary goal of pain relief.ObjectiveThe present study provides intraoperative strategies for trigeminal nerve (TN) management in patients with TGN secondary to an EC and observed long-term follow-up outcomes.MethodsA total of 69 patients with TGN secondary to an EC at our hospitals were included (January 2011–June 2021). The same surgical team performed all surgeries using a retrosigmoid approach. After EC removal, different methods for TN management were used, including microvascular decompression (MVD), sharp capsulectomy, nerve combing and embedded cholesterol crystal excision. The epidemiological, clinical, and surgical data were extracted.ResultsThe total EC removal rate was 92.8% (64/69). All patients achieved initial pain relief postoperatively, and 12 patients (17.4%) experienced varying degrees of hemifacial hypesthesia, which was relieved within 3–6 months. Three patients (4.3%) reported partial pain recurrence within a median follow-up period of 5.5 (0.5–10.5) years, which was relieved completely after low-dose carbamazepine administration.ConclusionThe primary goal of surgical tumor removal for patients with TGN secondary to an EC is relief of the main symptom of tormenting pain. The selection of an appropriate strategy for TN, including MVD, sharp capsulectomy, nerve combing or embedded cholesterol crystal excision, should depend on the patient's situation.

Incidence and Surgical Outcome of the Intracranial Epidermoid Cyst at Punjab Institute of Neurosciences Lahore, Pakistan

Objectives: The incidence and microsurgical outcomes of intracranial epidermoid cysts in the Department of Neurosurgery III, Punjab Institute of Neurosciences (PINS), Lahore, Pakistan, are described in this case series.&#x0D; Materials and Methods: This study was a data analysis of a case series of 15 patients (mean age, 40 years) of both gender with intracranial epidermoid cysts who had microsurgical surgical excision over five years.&#x0D; Results: This study comprised 11 (73.3%) male and 4 (26.7%) female patients, 11 (73.3%) cases were infratentorial and 4 (26.7%) cases were in supratentorial region. The epidermoid was located in the CP angle in 11 (73.3%) patients, 3 (20%) in the midline supra sellar region, and 1 (6.66%) in the frontotemporal region. The presenting complaints were mainly headache in 11 (73.33%), cranial nerve palsy and cerebellar signs in 8 (53.3%) patients, Trigeminal neuralgia in 3 (20%) patients, Fits and hydrocephalus in 2 (13.3%) patients. There were 14 (93.3%) patients with GTR (gross total resection), 1 (6.6%) patients STR (subtotal resection). According to Karnofsky's performance scoring (KPS), 3 (20%) patients improved, 11 (73.3%) patients had the same KPS, and 1 (6.6%) patient had a lower KPS.&#x0D; Conclusion: The epidermoid cysts in the brain are usually found in the infratentorial region rather than the supratentorial region. Infratentorial lesions typically cause cranial nerve deficits, whereas the supratentorial area symptom is a headache.

Correlation of radiological features of white epidermoid cysts with histopathological findings

Epidermoid cysts are benign congenital extra-axial lesions commonly found in the posterior fossa. These lesions have a characteristic imaging appearance on computed tomography (CT) scan and magnetic resonance imaging (MRI), but occasionally they may exhibit atypical radiological features, showing unusual hyperintensity on T1-weighted images (T1WI). Currently, such atypical appearance is referred to as white epidermoid. We present the imaging features of 5 cases of white epidermoid cyst and discuss the possible underlying etiology of this unusual radiological appearance. We retrospectively searched our electronic radiology database from January 2005 to December 2015 for all intracranial epidermoid cysts, which were confirmed either by typical MRI appearance or histopathological examination. All white epidermoid cases were evaluated with non-enhanced CT scan and multisequential MRI. Histopathological correlation was carried out in four white epidermoid cases. A total of 61 patients with epidermoid cyst were found, of those 5 (8%) were considered white epidermoids. These consisted of 3 females and 2 males, ranging in age between 31–63 years (average age was 51.8 years). Three patients had lesions located in the posterior fossa. The 2 other patients had lesions in the suprasellar region, with extension to the right middle cranial fossa in one. All 5 lesions were hyperdense on CT scan and hyperintense on T1WI. One patient demonstrated evidence of transformation of a classic epidermoid to a white epidermoid after partial resection. Histopathologically, cholesterol clefts were seen in 3 epidermoid cysts, each which also showed microcalcifications, proteinaceous material or melanin. Hemorrhage was demonstrated in one additional lesion. White epidermoid cyst is an unusual intracranial lesion that should be considered when encountered with an extra-axial T1 hyperintense lesion. The cause of this hyperintensity is not clearly understood, but the presence of cholesterol, microcalcifications, proteinaceous content and rarely hemorrhage or melanin may be contributing factors.

Malignant Transformation of Intracranial Epidermoid Cyst to Squamous Cell Carcinoma, Case Report and Literature Review

Intracranial Epidermoid cysts (ECs) are rare, benign tumor of central nervous system that appears from maintain ectodermal implants. Malignant transformation of an EC to squamous-cell carcinoma (SCC) is rarely reported. Intracranial squamous cell carcinoma has known as a poor prognosis condition that optimal modalities remain uncertain. We present the case of 43-years old male complained 3 months severe headache and right eye hemianopia. Primary evaluation depicted right homogenous brain mass which was successfully totally removed. Pathological assessment found epidermoid cyst without any sign of malignancy. Six months later, patient was referred with episodes of intermittent headache and right eye blindness. After initial imaging, new tumor was growth in same site of frontal epidermoid cyst. Second surgery was performed and pathological report discloses to be a malignant SCC. SCC transformation was confirmed by two expert neuro- pathologists. The exact underlying mechanism causing malignant transformation is not definitely known and it seems SCC may have been transformed due to chronic inflammatory respond to epidermoid cyst. Literature reviews demonstrate that, although, optimal total resection in addition adjuvant radiotherapy is the recommended management of choice, patient’s general survival of this condition is generally poor and long-term follow-up is important.

Intracranial Epidermoid Cyst: A Rare Case Series of 3 Patients

Of the intracranial epidermoids, temporal pole, interhemispheric region and prepontine, premedullary and inter-peduncular cisterns epidermoid are rare and only few cases have been reported. This is a case series study of 3 patients with temporal pole, interhemispheric region and in prepontine, premedullary and inter-peduncular cisterns epidermoids surgically treated in our institution. The age at the time of presentation varied between 40 and 65 years and 2 were males and one female. The presenting feature was headache, giddiness and visual disturbances. On computerized tomography scan the lesions showed dense calcification. On magnetic resonance imaging, the lesions were located in the temporal pole, interhemispheric region and in prepontine, premedullary and inter-peduncular cisterns with heterogenous signal intensities. All 3 patients underwent surgical resection. Keywords: Temporal pole epidermoid cyst, Interhemispheric epidermoid cyst, Prepontine epidermoid cyst, Intracranial Epidermoid Cyst

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

ObjectivePrimary 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.MethodsThe 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.ResultsThe 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.ConclusionMalignant 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.