Intrathalamic epidermoid tumor. Case report

A Rare Case of a Compressive Intracranial Epidermoid Cyst in a 13-Year-Old Patient

Pediatric intracranial epidermoid tumors are rare, slow-growing benign cystic lesions primarily originating from the ectodermal cell line during human embryogenesis. Intraparenchymal epidermoid tumors typically present with headaches, seizures, and focal neurological deficits. Although CT of the brain may show non-specific findings, MRI studies are more reliable and have a high confidence value in diagnosing intracranial epidermoid cystic lesions. We report a young girl who presented with headaches and blurring of vision for a three-week duration. An MRI of her brain revealed a cystic lesion on the right side of the interpeduncular cistern and cerebellopontine angle (CPA) extending to the right optic chiasm, suggestive of an epidermoid tumor. The aim of reporting this case is to highlight the significance of having a high clinical suspicion of intracranial tumors based on the patient's clinical manifestations.

Intracranial posterior fossa proliferating trichilemmal tumor: first case report

Proliferating trichilemmal tumors (PTT) are rare benign lesions that predominantly occur in elderly women and usually affect the scalp. They originate from the outer root sheath of hair shafts and have trichilemmal differentiation on histopathological examination. Compared to trichilemmal cysts, PTTs show increased cell proliferation and variable cytological atypia. We report the first case of a patient with an intracranial PTT in the posterior fossa. The clinicoradiological presentation and surgical management of the patient as well as the possible pathogenesis of this tumor are discussed.

Nonneoplastic and noninfective cysts of the central nervous system: A histopathological study

Nonneoplastic epithelial cysts involving the central nervous system are diverse and are predominantly developmental in origin. This study represents a surgical series describing the histopathological features of 507 such epithelial cysts with clinical and imaging correlation. Age at surgery ranged from 7 months to 72 years (mean: 33 years) affecting 246 male and 261 female patients. Colloid cyst was the most frequently resected cyst, followed by epidermoid cyst, arachnoid cyst, Rathke cleft cyst, dermoid cyst, neurenteric cyst, Tarlov cyst, and choroid plexus cyst. Diagnosis was based on the location of the cysts and the nature of the lining epithelium. Rathke cleft cyst showed the highest propensity for squamous metaplasia, significant inflammation, and xanthogranulomatous reaction. Ulceration of lining epithelium and calcification were most frequent in dermoid cyst. Radiopathological concordance was maximal for colloid cyst, followed by epidermoid and arachnoid cysts. Epidermoid and dermoid cysts exhibited the highest propensity for local tumor progression, followed by Rathke cleft cyst.

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.

Importance of appropriate surgical approach selection for radical resection of cerebellopontine angle epidermoid cysts with preservation of cranial nerve functions: our experience of 54 cases

BACKGROUND

Although many reports state that only the lateral suboccipital retrosigmoid approach (LSO) should be used for removal of cerebellopontine angle (CPA) epidermoid cysts, it is preferable to use various surgical approaches as appropriate for each patient, for radical resection with an optimal operative field under direct visualization, and for the preservation of cranial nerve (CN) functions. In the present study, we hence focused on the importance of surgical approach selection for removal of CPA epidermoid cysts and analyzed the results of CPA epidermoid cysts after surgery in our series.

METHODS

Fifty-four patients who underwent surgery for CPA epidermoid cysts were retrospectively analyzed, regarding their surgical approaches, removal rates, preservation rates of CN function 1 year after surgery, and recurrence. Surgical approaches were selected for patients according to the size and extension of the tumor.

RESULTS

Surgical approaches consisted of LSO (20 cases), anterior transpetrosal approach (ATP; 3 cases), combined transpetrosal approach (27 cases), and ATP + LSO (4 cases). Mean tumor content removal and capsule removal rates were 97.4% and 78.3%, respectively. Preservation rates of facial nerve function and useful hearing were 94.4% and 90.7%, respectively. The mean postoperative follow-up time was 62.8 months, and there were two cases of recurrence requiring reoperation about 10 years after surgery.

CONCLUSIONS

For CPA epidermoid cyst surgeries, selection of the appropriate surgical approach for each patient and radical resection with an optimal operative field under direct visualization enable tumor removal without the need for reoperation for a long time, with preservation of CN functions.

Clinicoradiological Features and Treatment Outcome of Supratentorial Intraparenchymal Epidermoid Cyst: A Report of Five Cases and Literature Review

Objectives  Intraparenchymal epidermoid cysts (IECs) are rare lesions. They represent less than 1% of the intracranial epidermoid cysts. The supratentorial IEC is a clinically and prognostically distinct subset. Given the rarity, most of the articles are case reports. We present a series of five cases of supratentorial IEC to characterize their clinical presentation and outcome, with emphasis on the surgical features.

Materials and Methods  We searched our database for all cases of intracranial epidermoid cysts operated between January 2005 and January 2020. Five patients were identified having IEC from the hospital information system and the neurosurgical operation record book. Standard craniotomy and decompression of the lesion were performed in all these patients. Standard postoperative care includes computed tomography scan of head on the day of surgery and magnetic resonance imaging of brain after 6 weeks to look for the residual lesion, if any. Subsequent follow-up visits in outpatient department to look for resolution of the presurgical symptoms.

Results  The mean age of the patients in our series was 28.8 years (range: 28–40 years.). All the five patients were male. Four patients had IEC involving frontal lobe and one in parietal lobe with a small occipital lobe extension. Seizure was the most common presenting complaint followed by headache. Complete excision was achieved in all the cases. All the three patients with seizure attained seizure freedom postlesionectomy. Focal neurological deficits resolved gradually in postoperative period. There was no recurrence of lesion during follow-up.

Conclusion  Supratentorial IEC most commonly affects young males, involve frontal lobe and present clinically with seizure. Complete surgical excision offers best outcome in the form of remission of seizure disorder.

A unique case of medulla oblongata epidermoid cyst

Epidermoid cysts (ECs) are slow-growing, benign tumors that represent <2% of all intracranial tumors. ECs can be divided into following two types: extra-axial and intra-axial. Extra-axial ECs are most often positioned in the cerebellopontine angle. Intra-axial ECs, which are also referred to as intraparenchymal ECs, are most commonly found in supratentorial structures, such as the frontal and temporal lobes, accounting for <2% of all intracranial ECs and are especially rare in children. In this report, we described a unique case of medulla oblongata EC in a child, to contribute this knowledge to the existing body of literature.

Extent of resection of epidermoid tumors and risk of recurrence: case report and meta-analysis

OBJECTIVE

Intracranial epidermoid tumors are slow-growing, histologically benign tumors of epithelial cellular origin that can be symptomatic because of their size and mass effect. Neurosurgical resection, while the treatment of choice, can be quite challenging due to locations where these lesions commonly occur and their association with critical neurovascular structures. As such, subtotal resection (STR) rather than gross-total resection (GTR) can often be performed, rendering residual and recurrent tumor potentially problematic. The authors present a case of a 28-year-old man who underwent STR followed by aggressive repeat resection for regrowth, and they report the results of the largest meta-analysis to date of epidermoid tumors to compare recurrence rates for STR and GTR.

METHODS

The authors conducted a systemic review of PubMed, Web of Science, and the Cochrane Collaboration following the PRISMA guidelines. They then conducted a proportional meta-analysis to compare the pooled recurrence rates between STR and GTR in the included studies. The authors developed fixed- and mixed-effect models to estimate the pooled proportions of recurrence among patients undergoing STR or GTR. They also investigated the relationship between recurrence rate and follow-up time in the previous studies using linear regression and natural cubic spline models.

RESULTS

Overall, 27 studies with 691 patients met the inclusion criteria; of these, 293 (42%) underwent STR and 398 (58%) received GTR. The average recurrence rate for all procedures was 11%. The proportional meta-analysis showed that the pooled recurrence rate after STR (21%) was 7 times greater than the rate after GTR (3%). The average recurrence rate for studies with longer follow-up durations (≥ 4.4 years) (17.4%) was significantly higher than the average recurrence rate for studies with shorter follow-up durations (< 4.4 years) (5.7%). The cutoff point of 4.4 years was selected based on the significant relationship between the recurrence rate of both STR and GTR and follow-up durations in the included studies (p = 0.008).

CONCLUSIONS

STR is associated with a significantly higher rate of epidermoid tumor recurrence compared to GTR. Attempts at GTR should be made during the initial surgery with efforts to optimize success. Surgical expertise, as well as the use of adjuncts, such as intraoperative MRI and neuromonitoring, may increase the likelihood of completing a safe GTR and decreasing the long-term risk of recurrence. The most common surgical complications were transient cranial nerve palsies, occurring equally in STR and GTR cases when reported. In all postoperative epidermoid tumor cases, but particularly following STR, close follow-up with serial MRI, even years after surgery, is recommended.

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

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

Rare giant epidermal cyst in the infratemporal fossa and middle cranial fossa

A 50-year-old man presented with a rare giant crossing cranium-temporal combined epidermal cyst. Physical examination found left facial numbness and temple severely numbness with light pressure. Horizontalis craniocerebral computed tomography demonstrated a mass lesion of 3.0 × 2.0 cm in the middle cranial fossa area; sagittal craniocerebral magnetic resonance scanning demonstrated a mass consisting of 2 leaves (the upper one, 4.0 × 3.0 cm; the lower one, 2.0 × 1.5 cm). Computed tomography angiography showed that the blood supply of the lesion came from superficial temporal artery and middle cranial fossa artery. The clinical diagnosis was neurilemmoma. Surgery revealed a pearly cyst consisting of 2 leaves (connected by a narrowed bridge located at the articular fossa of temporal bone) was 6 × 3 × 3 cm. Histologic examination disclosed disintegrated keratinizing epithelium layer, keratinizing epithelium layer, and stratified squamous epithelium layer from inner to outer and found no hair follicles or sebaceous gland with the diagnosis of epidermoid cyst. Surgery was successfully performed, and the patient was discharged home with severer left facial numbness relatively and left jaw slight opening. The present case suggests that epidermoid cysts can be seen in any location, even giant crossing cranium-temporal combined lesion, and the blood supply should be considered as a factor judging its pathogenesis.

Epidermoid tumors of the temporal lobe as epileptogenic foci

Intracerebral epidermoid tumors of the temporal lobe are exceedingly rare. The vast majority of these slow-growing tumors remain clinically silent while only a select few are associated with overt symptomatology. We report two patients with epidermoid tumors whose unique location in the temporal lobe resulted in secondarily generalized seizures. Our first patient, a 19-year-old female, presented with a secondarily generalized tonic-clonic seizure and MRI revealed a superior temporal lobe lesion that was subsequently treated with an awake craniotomy and gross total resection. Our second patient was a 71-year-old male with a recent seizure history and known left temporal lobe lesion. The patient underwent craniotomy for gross total resection of the mass. In these two patients, we found that MRI proved diagnostic and surgical resection was curative. Our clinical experience and review of the literature indicate that gross total resection of these lesions confers control of localization-related epilepsy.

A supratentorial, hemorrhagic, intraparenchymal epidermoid cyst

Epidermoid cysts are slow growing benign tumors that represent < 1-2% of all intracranial tumors and rarely present as supratentorial, intraparenchymal masses. We present the first report of a supratentorial, hemorrhagic, intraparenchymal epidermoid cyst with its presentation, our operative approach, post-operative course, radiographic features, and a literature review.

CT and MR imaging features of intracerebral epidermoid--a rare lesion

We present a rare case of intracerebral epidermoid cyst with partial calcification on CT and a characteristic hyperintense signal on diffusion-weighted MR imaging (DWI). MR imaging with DWI may help to accurately distinguish the lesion from other cystic tumours of the brain.

Pathogenesis of intraparenchymal epidermoid cyst in the brain: a case report and review of the literature

BACKGROUND

Intracranial epidermoid cysts are relatively common; however, epidermoid cysts in the brain parenchyma are rare. In addition, the etiology of intraparenchymal epidermoid cysts is not clear.

CASE DESCRIPTION

A 61-year-old woman presented with convulsive seizures. CT and MRI revealed a mass lesion in the right parietal lobe. With low-grade glioma as a preoperative diagnosis, the tumor was totally excised, but the subsequent pathologic diagnosis was epidermoid cyst.

CONCLUSION

Exact preoperative diagnosis of this disease would be helpful in preventing chemical meningitis. The etiology is likely related to the time and locus of sequestration of ectodermal tissue during fetal development. Clarifying the pathogenesis will lead to effective preventive measures.

Malignant squamous degeneration of a cerebellopontine angle epidermoid tumor. Case report

The authors present the case of a woman with a cerebellopontine angle (CPA) epidermoid cyst that degenerated into a squamous cell carcinoma. Malignant degeneration of an epidermoid cyst is an extremely rare occurrence. Malignant transformation must be considered in the differential diagnosis when new contrast enhancement on imaging studies and progressive neurological deficit are seen in a patient harboring an epidermoid cyst. The patient initially presented with a 10-year history of left trigeminal neuralgia, subacute left-sided hearing loss, and with facial weakness of 3 weeks' duration. Initial magnetic resonance (MR) imaging revealed a left CPA mass, consistent with an epidermoid. There was faint contrast enhancement where the tumor was in contact with the lateral brainstem. A subtotal resection was performed. Histopathological findings were consistent with an epidermoid tumor. One year after initial presentation, the patient's neurological deficit had increased, and follow-up MR imaging demonstrated a large contrast-enhancing tumor filling the left CPA and compressing the brainstem. At repeated surgery a squamous cell carcinoma arising from the previous epidermoid was found. The patient was subsequently treated with external-beam radiotherapy and stereotactic radiosurgery. Her tumor stabilized. Three years and 8 months after the patient's initial presentation, a new area of tumor developed at the torcular Herophili. The patient died shortly thereafter. Malignant squamous degeneration is a rare cause of enhancement on MR images, as is progressive neurological deficit in a patient with an epidermoid. The combination of subtotal resection, external-beam radiotherapy, and stereotactic radiosurgery may be useful for local tumor control but the long-term prognosis is guarded.

[Epidermoid cyst of the third ventricle]

Intracranial epidermoid tumours are very rare lesions of ectodermal origin that account for 1% of all intracranial tumours. The favourite sites affected by these tumours are the cerebellopontine angle and the chiasmal region. They also appear in the cerebral hemisphere and the intraventricular cavities. We report a case of epidermoid tumour of the third ventricle. The patient was a 68 year-old woman admitted in our service with a 7-days history of headaches and intermittent nausea and vomiting. A CT scan of the brain revealed a large hypodense mass in the third ventricle associated with hydrocephalus. An MRI was performed and revealed, on T1-weighted image, an irregular nonhomogeneous lower signal in relation with CSF. This tumour showed a very bright signal intensity on T2-weighted images. A transcallosal approach of the tumour mass was performed via a right frontal craniotomy. Using an ultrasonic aspirator, the tumour was removed. In a review of the literature, we found only 8 reported cases.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Epidermoid tumor of the interhemispheric fissure

In this report, we present a case of an interhemispheric epidermoid presenting with generalized seizure. The tumor was demonstrated radiologically and discussed with the pertinent literature.

Experience with cerebellopontine angle epidermoids

OBJECTIVE

Cerebellopontine angle (CPA) epidermoids, although of benign nature, are of considerable neurosurgical interest because of their close proximity and adherence to the cranial nerves and the brain stem. We describe our experience and attempt to correlate the final outcomes with the extent of surgical removal.

METHODS

Twenty-five consecutive patients with CPA epidermoids that were surgically treated were reviewed, and the final outcomes were assessed.

RESULTS

Thirteen patients had trigeminal neuralgia. In 7 of the 13 patients, trigeminal neuralgia was the only presenting feature. The epidermoid was confined to the CPA in each of 6 patients, and in each of 18, it had varying degrees of supratentorial extension. One patient had a predominant supratentorial epidermoid with extension to the CPA. The lesions were totally excised in 12 patients. Near-total removal was accomplished in eight patients, and in the remaining five, partial removal was accomplished. Transient worsening of the cranial nerve functions occurred in 11 patients, probably as a result of aggressive dissection of the capsule from the cranial nerves. In 9 of the 11 patients, the cranial nerve functions improved by the time of discharge. All of the patients who had trigeminal neuralgia were relieved of their symptoms. Eighteen patients were followed up for a mean period of 42 months, and none had symptoms of recurrence.

CONCLUSION

Aggressive surgical removal results in transient but significant cranial nerve dysfunction in the postoperative period. A conservative approach is indicated for patients in whom the capsule is adherent to the brain stem and the cranial nerves.

Cranial cystic epidermoid: report of two cases and review of the literature

Intercranial epidermoid tumours are benign lesions of congenital origin that are potentially curable. Although computerized axial tomography (CT) and magnetic resonance imaging (MRI) are usually diagnostic, a few atypical features sometimes make pre-operative diagnosis difficult. Two cases of cystic epidermoids with peripheral ring enhancement are reported. Relevant literature has been reviewed.

Subcortical aphasia from a thalamic abscess

A patient is reported who was treated successfully for a left thalamic abscess that resulted in subcortical aphasia. A SPECT scan showed large areas of hypoperfusion in the cortex of the left hemisphere. At follow up after seven months there was marked improvement in the language disorder and the cortical hypoperfusion. It is suggested that aphasia in patients with subcortical lesions results from secondary cortical dysfunctions. The evidence is confined to patients with stroke lesions. The possible implications of this case on current theories of pathophysiological mechanisms, in particular the ischaemic penumbra theory and the cortical diaschisis theory, are briefly discussed. Cortical diaschisis may be the appropriate explanation in this patient.

Cystic intracerebellar epidermoids with rim enhancement. A case report

A case of two infected cystic epidermoids of the right cerebellar hemisphere is reported. One of the cysts showed peripheral contrast enhancement on CT. Relevant literature regarding the pathogenesis and CT diagnosis is reviewed.