Diagnosis of epidermoid tumor by computed tomography. Analysis and evaluation of findings

Fourth Ventricular Epidermoid Cyst - Case Series, Systematic Review and Analysis

Background:

Epidermoid cysts are extra-axial, pearly white avascular lesions mostly found in the cerebellopontine region. They are slow-growing and mostly become symptomatic when they attain significant size. They do occur at other anatomical locations, but fourth ventricle is a rare location. Three representative cases with their outcomes are described here.

Methods:

The systematic review was done with adherence to predefined criteria. The studied variables were age, gender, duration of symptoms (DOS), clinical features, hydrocephalus (HCP), extent of resection, postoperative complications, outcome, follow–up, and recurrence. Statistical analysis was done to identify predictive factors for outcome.

Results:

Final analysis included 58 studies containing 131 patients. The most common clinical feature was cerebellar dysfunction (93%). The most common cranial nerve involved was the abducens nerve (n = 37, 28.46%). Preoperative HCP was present in nearly a third (35%) of patients. The outcomes were not different with age (P = 0.23), gender (P = 0.74), DOS (P = 0.09), and HCP (P = 0.50). Improved outcomes were associated with total resections (P = 0.001), absence of preoperative cranial nerve dysfunctions (P = 0.004), and presentation with features of raised intracranial pressure (P = 0.005). Longer DOS (mean 76.74 months) was associated with significantly increased cranial nerve nuclei involvement (P = 0.03). Aseptic meningitis was reported in 14.5% of cases. Recurrences were infrequently reported (n = 9).

Conclusions:

Although the fourth ventricular epidermoid lesions are difficult to detect in an innocuous stage, when found, they should be extirpated early and totally, as a longer DOS leads to cranial nerve dysfunctions and suboptimal outcomes.

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.

Long term outcome in surgically treated posterior fossa epidermoids

OBJECTIVES

To study posterior fossa epidermoids treated surgically at our institute and to compare their long term outcome with respect to extent of surgical decompression.

MATERIALS AND METHODS

Retrospective analysis of 50 cases of posterior fossa epidermoid surgically treated at our institute between 1997 and 2007.

RESULTS

The mean duration from onset of symptoms to surgery was 2.5 years. Patients with cerebellopontine angle (CPA) epidermoids presented predominantly with trigeminal neuralgia (35%) and hearing loss (29%) while patients with fourth ventricle epidermoids had features of raised intracranial pressure (ICP) and gait ataxia (69.2% each). The rate of recurrence was 9% in tumors considered totally removed and 93% in those subtotally removed. Of the 17 patients with recurrences, 3 (7.9%) underwent a second operation. The mean duration of follow up at first recurrence was 9.3 years.

CONCLUSION

Based on our experience, the rate of recurrence is significantly higher after subtotal removal as compared to total removal of epidermoids on long-term follow up. Symptomatic recurrence requiring re-exploration is evident only after a long duration (∼10.9 year) following primary surgery. Hence, total removal without producing new neurological deficits should be the standard goal when operating on posterior fossa epidermoid cysts.

Recurrent meningitis due to epidermoid

Aseptic meningitis is characterized by noninfective serous inflammation of the meninges. It can occur in a recurrent fashion when associated with dermoid and epidermoid cysts due to rupture of cyst contents into subarachnoid space resulting in aseptic chemical meningitis. Bacterial meningitis in association with these tumors is commonly related to a coexisting dermal sinus tract and the most common organism is Staphylococcus aureus.

Intradiploic epidermoid causing spontaneous extradural hematoma: case report

OBJECTIVE

A case of an intradiploic epidermoid tumor leading to spontaneous extradural hematoma is reported. Intradiploic epidermoids are not common intracranial tumors. This is the first reported case of intradiploic epidermoid presenting as a spontaneous extradural hematoma.

CLINICAL PRESENTATION

The patient presented with sudden onset of headache and deterioration in the sensorium. A computed tomographic scan revealed a lesion causing erosion of both tables of the calvarium and a mixed intensity extradural hematoma.

INTERVENTION

The patient underwent immediate operation, and evacuation of the hematoma and excision of the tumor were performed.

CONCLUSION

Intradiploic epidermoid tumors so rarely present with extradural hemorrhage that prophylactic removal cannot be recommended in all such cases. However, in view of the seriousness of the hemorrhage, prophylactic removal may be recommended, especially if the patient, such as a sportsman, child, or elderly person, is prone to injuries.

Epidermoids of the cerebellopontine angle: a 20-year experience

BACKGROUND

There is considerable debate within the current literature whether total or subtotal removal of CPA epidermoids yields better long-term outcomes. The aim of this study was to review our experience with cerebellopontine-angle epidermoid tumors, as well as the current literature, focusing on the correlation between long-term outcome and the extent of surgical removal.

METHODS

We performed a retrospective review of 24 patients with epidermoid tumors of the CPA surgically treated at our institution between 1985 and 2005.

RESULTS

The mean duration from onset of symptoms to surgery was 3.1 years. Cranial nerve dysfunction was noted in 83% of patients preoperatively. Total removal was achieved in 13 patients, near total removal in 6 patients, and subtotal removal in 5 patients. Patients who underwent total removal had a median MRS score of 0, whereas those who underwent near/subtotal removal had a median MRS score of 1. The rate of recurrence was 23% in tumors considered totally removed and 27% in those near/subtotally removed. Of the 6 patients with recurrences, 5 underwent a second operation. The mean duration of follow-up was 4.2 years.

CONCLUSIONS

Total removal of CPA epidermoids does not result in significantly increased morbidity and mortality and should be the goal of surgical treatment. However, near/subtotal resection of lesions that extend far beyond the CPA or are densely adherent to neurovascular structures is justified, as there is no significant difference in the rate of recurrence.

Malignant transformation of posterior fossa epidermoid cyst

The authors report the case of a 45-year-old man who presented with a short duration of a painful ophthalmoparesis. Initial magnetic resonance imaging revealed an extraaxial petroclival mass characteristic of an epidermoid cyst, with the exception of a contiguous contrast-enhancing lobule. A subtotal resection was performed with the histopathological diagnosis revealing malignant transformation of an epidermoid cyst. Despite aggressive postoperative adjuvant therapy, the patient developed leptomeningeal metastasis and died shortly thereafter. The presence of contrast enhancement at the site of an epidermoid cyst combined with an acute, progressive neurological deficit should alert the treating physician to the possibility of a malignant transformation. When transformation does occur, the clinical and radiological course is quite aggressive as compared with the indolent growth of epidermoid cysts. Treatment options include surgery with adjuvant chemotherapy or radiotherapy. We review the pertinent features of this case along with the relevant literature regarding primary intracranial squamous cell carcinomas.

Pineal epidermoid cysts: a study of 24 cases

BACKGROUND

A retrospective analysis of clinical features and management strategy in 24 cases of epidermoids in the pineal region is done. Long-term outcome of radical surgical resection is analyzed.

METHODS

Twenty-four patients having epidermoids in the pineal region were surgically treated in our department during an 11-year period (1992 up to 2003). These cases were retrospectively analyzed. The average duration of follow-up was 5.2 years.

RESULTS

The age at the time of presentation ranged from 13 to 51 years (mean, 29.2 years). There were 15 male and 9 female patients. The average duration of complaints was 7 months. Headache and ataxia were the commonest symptoms. The infratentorial-supracerebellar approach and the interhemispheric posterior parietooccipital route were used to excise the epidermoids in 20 and 3 patients, respectively. In one patient, the tumor was removed in 2 stages, first by the infratentorial-supracerebellar approach and subsequently by the interhemispheric posterior parietooccipital surgical approach. Total excision of the solid part of the tumor and the capsule was achieved in 6 patients. In 13 cases, the solid part of the tumor was completely resected, but at least, a part of the tumor capsule was left behind. In 5 cases, a part of the solid portion of the tumor was either deliberately or inadvertently left behind. Incomplete tumor resection was primarily due to adhesions of the capsule to large veins in the region, dissection around which was considered hazardous, and extensive and invasive nature of extension of the tumor. During the period of follow-up, one patient had asymptomatic growth of the residual tumor after 6 years of surgery. One patient with residual tumor continued to get generalized seizures. All patients are leading active lives.

CONCLUSION

Radical surgery for pineal region epidermoid tumors is associated with an excellent immediate postoperative and long-term outcome.

Intracranial epidermoid cysts: diffusion-weighted, FLAIR and conventional MR findings

PURPOSE

To compare diffusion-weighted echo-planar imaging (DW) with spin-echo (SE), and fluid-attenuated inversion recovery (FLAIR) sequences in the evaluation of epidermoid cysts (ECs), and to evaluate T2 shine-through effect.

MATERIALS AND METHODS

Fifteen patients were imaged prospectively in two different 1.5 T magnetic resonance (MR) units with standard head coils with SE, FLAIR and DW echo planar imaging sequences. The qualitative and quantitative assessments were performed by two radiologists in consensus. Apparent diffusion coefficient (ADC) values were obtained from all ECs. Exponential DW images are obtained in 11 cases to eliminate T2 shine-through effects. The results are analyzed with variance analysis (ANOVA) and Bonferroni t method.

RESULTS

FLAIR sequence was superior to T1- and T2-weighted sequences in showing ECs. In 13 cases, the borders of the lesions could be delineated from the surrounding structures with only DW imaging where ECs were markedly hyperintense. The ADC values of ECs are significantly lower than CSF (P < 0.001), and significantly higher than deep white matter (P < 0.01). On exponential DW images, ECs had similar intensity with brain parenchyma showing that the real cause of the hyperintensity of the lesions on trace images is the enhanced T2 effect of the tissue.

CONCLUSION

FLAIR sequence is superior to the conventional MR sequences in demonstrating the ECs and DW imaging is superior to other MR sequences in delineating the borders of the ECs. Exponential DW images had shown that the hyperintensity in the trace images are caused by increased T2 effect of the lesion rather than the decrease in ADC values.

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.

Magnetic resonance appearance of multiple intracranial epidermoid cysts: intrathecal seeding of the cysts? Case report

A 44-year-old man presented to the hospital with multiple intracranial epidermoid cysts. The clinical manifestations of his disease included chronic headaches and one seizurelike episode. Findings determined by magnetic resonance (MR) imaging, surgery, and histological analysis indicated intrathecal and intraventricular seeding of the cysts. Spontaneous (nontraumatic) seeding of multiple daughter cysts from intracranial epidermoid cysts is still very rare and their multiple appearances on MR imaging should be distinguished from the simple scattering of oily contents due to cyst rupture.

Assessment and surgical management of posterior fossa epidermoid tumors: report of 28 cases

OBJECTIVE

The management of a series of 28 patients operated on for posterior fossa epidermoids is reviewed, emphasizing the need for long-term follow-up. We discuss the rationale for a comprehensive classification system that may allow the comparison of results from homogeneous series.

METHODS

We grouped the tumors to differentiate the surgical management according to various tumor sites and the degree of extension. Twenty patients harbored tumors located in the cerebellopontine angle, five patients harbored tumors in the fourth ventricle, and three patients harbored tumors in the posterior fossa basal. In 17 patients, extensions of tumors outside the posterior fossa included the following regions: the suprasellar/ chiasmatic (n = 5), the parasellar/temporobasal (n = 5), and the mesencephalic/pineal (n = 7). Tumor extension was also defined by the number of regions involved. Pre- and postoperative magnetic resonance imaging and computed tomographic findings collected in 17 and 28 patients, respectively, were carefully evaluated.

RESULTS

Clinical features and surgical approaches varied according to location and growth pattern. Fifty-seven percent of the tumors were completely removed. A higher total removal rate was achieved in patients with tumors confined to the primary location. One patient (3%) died in the perioperative period. Approximately half of the patients presented with transient mild focal deficit impairments resulting from the manipulation of the nervous structure over a wide area. There was a higher rate of surgical complications with fourth ventricle and mesencephalic extended cerebellopontine angle tumors. The mean follow-up period was 8.6 years. Thirty percent of the patients with subtotal removal experienced symptomatic recurrences after 8.1 years, whereas all patients with total removal were still asymptomatic. The recurrence-free survival rate was 95% at 13 years for patients with total removal compared with 65% for patients with subtotal removal. Problems of identification of tumor regrowth are discussed.

CONCLUSION

By assessing posterior fossa epidermoids, we determined that location and extension play a major role in the prognosis. Our data suggest that more aggressive surgery is called for at first operation, and that a second operation should be planned when regrowth becomes symptomatic and/or tends to extend outside its original site.

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.

Epidermoid tumor of the occipital bone

Intradiploic epidermoid tumor of the occipital bone was presented. There were neither intracranial extensions nor neurologic deficits. The lesion started as a painless mass under the scalp. The total removal of the tumor was associated with a good prognosis.

Primary intracranial squamous cell carcinomas: report of two cases

Two cases of primary intracranial squamous cell carcinomas are reported. The first patient is a 57-year-old man with an epidermoid carcinoma in the right cerebellopontine angle, having histological features that indicated malignant transformation in a benign epidermoid cyst. The second patient is a 42-year-old man in whom squamous cell carcinoma arose in a pre-existing middle fossa dermoid cyst 9 years after the initial surgical resection. The literature on primary intracranial squamous cell carcinomas is reviewed, and the clinical features and histological pathogenesis for the occurrence of this unique condition are discussed.

Epidermoid tumour of the cerebellopontine angle: diagnosis by MRI

Epidermoids are the third most common cerebellopontine angle tumour, and their diagnosis in the last two decades has been largely obtained using computed tomography (CT). More recently magnetic resonance imaging (MRI) has become a valuable diagnostic tool, and the signal characteristics and enhancement pattern of an epidermoid following intravenous gadolinium with MRI is presented and the literature reviewed.

Long-term evaluation of asymptomatic patients operated on for intracranial epidermoid cysts. Comparison of the diagnostic value of magnetic resonance imaging and computer-assisted cisternography for detection of cholesterin fragments

Magnetic resonance imaging (MRI) and/or computer-assisted cisternography (CAc) assessment of latent late recurrences in long-term asymptomatic patients surgically treated for intracranial epidermoid cyst is here presented. MRI was exclusively utilized in one patient; CAc was exclusively employed in three patients with metalic operative clips; both CAc and MRI were employed in another four patients. CAc appears to be more reliable than MRI in detecting cholesterin fragments in asymptomatic patients operated on for intracranial epidermoid cyst.

Intracranial squamous cell carcinoma arising in an epidermoid cyst

Intracranial epidermoid cysts are uncommon benign tumors of developmental origin; malignant transformation is extremely rare. We report a case of squamous cell carcinoma arising in a chiasmatic-parasellar epidermoid cyst. Malignant change had not been suspected until histological examination revealed it.

Transtentorial epidermoid cysts

Epidermoid cysts may occur simultaneously above and below the tentorium. Eleven patients with involvement of both infra- and supra-tentorial cisterns are presented. In two cases the epidermoid, located mainly in the cerebello-pontine angle, spread into the middle cranial fossa; in three the epidermoid extended from the parasellar cisterns to the posterior cranial fossa; in six patients the epidermoid, enlarging the tentorial notch, occupied extensively both cranial fossae. The surgical approach was influenced both by the experience of the surgeon and by the main extension of the epidermoid. Total removal was feasible in two patients only but only one of the eleven patients had a recurrence of the epidermoid. The long term results appear to be unrelated to the size of the epidermoid and to the choice of approach.

Magnetic resonance of intracranial epidermoids

The magnetic resonance images of seven patients with biopsy-proven epidermoids were evaluated. The epidermoids were hypointense on T1-weighted images. Intermediate density images revealed the tumors to be heterogeneous in signal intensity consisting of areas of hypo- and isointensity. Signal intensity on T2-weighted images was hyperintense and inhomogeneous in all but one case. CT performed in five patients demonstrated the tumors to be well-defined hypodense lesions without contrast enhancement.

Parapontine epidermoid tumours presenting as trigeminal neuralgias: anatomical findings and operative results

Four cases of medically intractable trigeminal neuralgia caused by parapontine epidermoid tumours are reported. All patients presented with typical trigeminal neuralgia and low-density area in the parapontine region on CT-scans. Neurologically in all cases slight hypaesthesia in various divisions of the trigeminal nerve without other neurological signs was revealed. Trigeminal pain was completely relieved after surgery in all patients. Facial sensory disturbances and pain occur in patients with parapontine epidermoid tumour as a result of direct tumourous compression (and hypothetically toxic effects on the nerve root from the tumourous contents).

Dense epidermoid cyst of the cerebellopontine angle

A case of epidermoid cyst in the cerebellopontine angle which appeared as a hyperdense mass on CT is presented with clinical and radiological features. The preoperative tentative diagnosis proved erroneous. The literature is reviewed on this exceptionally rare radiological finding of epidermoid cysts and highlights of preoperative diagnosis are discussed.

Surgical treatment of intracranial dermoid and epidermoid cysts in children

Between 1956 and 1987 operations were performed on 36 patients below the age of 20 years for epidermoid and dermoid cysts of the central nervous system. Seventeen tumors were intracranial intradural lesions (47%): 12 were located in the supratentorial region (71%) and 5 were located in the infratentorial region (29%). Ten of these tumors (59%) were seated along the midline structures. The clinical presentation was consistent with the location of the tumors. The neuroradiological diagnosis was mostly made with the aid of pneumoencephalography, computed tomography (CT), nonionic contrast medium CT cisternography, and magnetic resonance imaging. Complete removal of the tumor contents was performed in all cases but one, although the completeness of removal of the tumor capsule could not be exactly estimated in some patients. At late follow-up only two tumor recurrences were observed. Radical removal of the tumor capsule of these congenital tumors, even when it is connected to vital neurovascular structures, seems advisable in patients who become symptomatic within the first two decades of life.

Intracranial epidermoid tumours: thirty-seven years of diagnosis and treatment

The clinical, operative and pathological characteristics of 102 consecutive cases of intracranial epidermoid tumours are reported. These cases constituted 1.1% of all intracranial tumours and 13.5% of congenital neoplasma admitted to our service in the period 1951-88. Of 91 (89.2%) intradural tumours, 74 (72.5%) were in the subarachnoid cisterns, especially in the cerebellopontine angle cistern (31 cases). The tumours were solid in 69 cases (67.6%) and cystic in 26 (25.5%); the remaining 7 cases were not recorded. There were no specific clinical features with which to identify the nature and extent of the tumour. Diagnosis and treatment are described, with an evaluation of CT and MRI. Before 1981, total removal rate of tumour was 29.3%; after that date it was 72.7% with the aid of microsurgery. The overall surgical mortality rate was 4.9% (5 cases), but there were no deaths in the microsurgical group. Follow-up for a period of 0.5-37 years (mean 13 years) was carried out in 68 patients (70.1%). Among 24 patients with incomplete removal, recurrence of tumour was verified in 4 cases; 3 underwent reoperation with excellent or good results. One patient refused operation and died. All the remaining 20 cases, save 3 who died of other diseases, returned to their normal activities without recurrent manifestations. The results suggest that the primary treatment of epidermoid tumours should be surgical removal including the contents and capsule of a tumour. With the aid of microsurgical technique, complete removal is possible. Patients with incomplete removal can also obtain a long-term favourable result.

Magnetic resonance imaging of the intracranial epidermoid

Magnetic resonance imaging (MRI) was performed in five cases of intracranial epidermoid. In three of the five patients, the low-density mass on the CT scans showed as low intensity on the T 1 and high intensity on the T2 weighted images. In the two other patients, the masses with high or isodensity on CT showed as high intensity on the T 1 weighted images and as high or low intensity on the T 2 weighted images. Thus, the intensity of epidermoid on MRI correlated fairly well with the CT density, although the former was more variable. The variety of intensities on MRI reflects differences in the chemical composition of the components in the epidermoid tissue in addition to differences in the solid and liquid state of the tissue. An epidermoid could have similar MRI findings as an arachnoid cyst with regard to intensities but its irregular margin provides a useful guide for differentiation. As in other tumours, MRI is superior for evaluation of the size and the extent of the epidermoid as well as the displacement of important neurovascular structures.

Magnetic resonance imaging of intracranial epidermoid tumours

Epidermoid tumours are rare lesions within the skull which are usually found in a cerebellopontine angle. In the computed tomography (CT) literature, they have been described as well-defined lesions of low density which seldom show calcification or tissue enhancement. We have recently encountered three intracranial epidermoids, which appeared to exhibit uniform findings on low field strength magnetic resonance (MR) of moderate signal intensity in the T1-weighted images and a bright signal (increased T2) in the T2-weighted sequences. It may be possible to predict accurately the presence of an epidermoid tumour when this particular configuration of findings is present.

Dermoids of the posterior fossa. Case reports and review

Three children are presented with dermoid cysts of the posterior fossa, one of the most common locations of dermoid. They were initially diagnosed as having abscesses. Clinical presentations included hydrocephalus and recurrent meningitis. A helpful clue for identification is a bony defect of the skull on plain film or on a bone-window at Computed Tomography (CT).

Epidermoid cysts of the fourth ventricle

Epidermoid tumors located in the fourth ventricle are exceedingly rare. Seven cases of this pathological condition were observed during a 10-year period. Patients were mostly middle-aged men, with a clinical history of relatively short duration (5 months). Clinical symptoms consisted of vertigo and ataxia, followed by incoordination, dysmetria, and tremor at a later stage. Computed tomography scanning represented the main diagnostic technique for these lesions, and typically showed a highly hypodense, round-shaped area within the fourth ventricle, occasionally accompanied by hydrocephaly. Subtotal surgical removal of the cysts produced excellent results in 86% of the cases. The implications of these findings are discussed.

Febrile convulsions in an adult as presenting symptom of intracranial dermoid cyst: a case report

A 32-year-old man had generalized tonic-clonic epileptic seizures associated with episodes of recurrent high fever for 6 years. Repeated physical examinations including neurological status, EEG and nuclear brain scan were negative. Brain CT showed a non-homogeneous parasellar cyst of low density and fat-fluid levels in the lateral ventricles. The diagnosis of intracranial dermoid cyst was confirmed at surgery and histopathologically. Recurrent febrile convulsions and chemical meningitis may be the only clinical manifestations of ruptured dermoid cyst. The CT features of intracranial dermoid cyst are pathognomonic.

Epidermoid cyst of the fourth ventricle

The case of a 52-year-old patient with a fourth ventricle epidermoid is reported. The initial presentation included long-standing headaches, progressive anomalies of gait and slight impairment of mentation. CT showed a hypodense mass enhancing peripherally after contrast infusion. Brain auditory evoked responses (BAER) showed asymmetric increased latencies. At operation, total removal of an extensive fourth ventricle epidermoid was achieved. A delayed meningitis occurred postoperatively. Physical examination was normal at the 2 year follow-up and BAER were improved. The etiological and clinical features of fourth ventricular epidermoids are briefly reviewed. The diagnostic value of CT is emphasised but the possibility of CT-dense epidermoid cysts deserves a special mention. Total removal of the neoplasm is the theoretical aim of operative treatment, but this purpose may be harmful when the ventricular floor is involved by the capsule.

MR imaging of epidermoid cysts

After a short review of literature, MRI assessments of four cases of epidermoid cysts (EC) are reported. EC, (characterized in computed tomography by hypo or iso-density areas non-enhanced by contrast), are characterized in MRI by: 1) an important variability of signal intensity between the different cases, and sometimes between the different parts of the same cyst, 2) the absence of edema in surrounding parenchyma, in spite of important mass effect, 3) well defined limits, permitting certainty of the extra-cerebral nature of this tumor, 4) the presence of calcifications easily perceptible in MRI. It is proposed that the variability of signal intensity of EC is caused by different relaxation time values corresponding to different concentrations of keratin, cholesterol and water content.

Posterior fossa epidermoid cysts

The authors present their clinical and surgical experience with 18 posterior fossa cholesteatomas, including three cases with atypical CT scan appearances that corresponded to calcification, haemorrhage or malignant change into an epidermoid carcinoma, respectively.

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.

NMR imaging of congenital intracranial germinal layer neoplasms

NMR images in five patients with surgically proved, congenital germinal layer intracranial neoplasms (two dermoid and three epidermoid tumors) were reviewed. The dermoids were typically midline (suprasellar or parapineal) masses with sharply-defined margins. Relaxation times were variable, but if fat was present, T1 was decreased, and T2 was increased. The epidermoids were off the midline (cerebellopontine angle, temporal lobe, frontal lobe) masses with generally long T1 and T2 relaxation times. Obstructive hydrocephaly was noted in one patient, and tumor to ventricular communication was demonstrated in another.

Intracranial epidermoids--concerning the low absorption value on computerized tomography

The authors analysed the contents of two intracranial epidermoids showing low density on computerized tomography. Although both cases had approximately similar composition, 85, 83% for water, 12, 12.5% for protein, 3, 4.5% for total lipid including cholesterol, respectively, the absorption values differed from each other. Both tumours were identified to communicate with CSF, one by delayed metrizamide CT scan and the other by direct aspiration during operation. The low absorption values in both cases resembled or were slightly higher than that of CSF in each case, and not a single pixel showed negative values for lipid. These findings suggest that it is the CSF content within the anatomical interstices or structural crevice of the tumour, rather than cholesterol, which is responsible for the low absorption values which appeared in the CT scan.

Epidermoid cysts of the posterior fossa

Epidermoid cysts originating in the paramedian basal cisterns of the posterior fossa are congenital lesions that grow to a large size through slow accumulation of desquamated epithelium. These lesions grow between and ultimately displace cranial nerves, vascular structures, and the brain stem, causing a long course of progressive neurological deficits. The onset of symptoms usually occurs during the fourth decade of life. Epidermoid cysts are easily diagnosed with computerized tomography scans, which characteristically show a low-density extra-axial pattern. The primary surgical objective is to decompress the mass by evacuating the cyst contents and removing nonadherent portions of the tumor capsule; portions of the capsule adherent to vital structures should be left undisturbed. Aseptic meningitis is the most common cause of postoperative morbidity, and its incidence may be minimized by intraoperative irrigation with steroids followed by systemic therapy with dexamethasone. Symptomatic recurrences that occur many years after surgery should be managed with conservative reoperation.

Diagnosis of epidermoid cysts by metrizamide CT cisternography

The authors describe three cases of intracranial epidermoid cysts specifically diagnosed by metrizamide CT cisternography. In CT cisternography of epidermoid cysts, metrizamide enters deep in the tumor clefts and depicts the lobulated margin of the tumor. We consider these findings are specific for this tumor and similar to the findings reported previously in pneumoencephalography or positive contrast cisternography.

Squamous cell carcinoma arising in a suprasellar epidermoid cyst. Case report

A case is presented in which a squamous cell carcinoma developed in an intracranial epidermoid cyst. The patient was a 54-year-old woman with a 3-year history of depression and amblyopia; no focal findings were noted and she was diagnosed as having psychiatric disorders. On her final admission she showed clinical evidence of a rapidly growing intracranial mass. Computerized tomography (CT) identified a right parasellar and temporal lesion which was then incompletely removed. The literature on primary intracranial squamous cell carcinoma is reviewed, and the role of CT scanning in preoperative diagnosis of this lesion is discussed.

Dense suprasellar epidermoid cyst. A case report

A case of a dense epidermoid cyst of the suprasellar cistern is presented. The clinical symptoms were headache radiating to the left eye and a quadrant anopsia on the left eye. The density of the epidermoid was 62 HU and no significant contrast enhancement occurred after contrast application. The main feature which allows differentiation from other hyperdense suprasellar lesions seems to be the lack of contrast enhancement.

Epidermoid tumor of the fourth ventricle: use of metrizamide-computed tomography

This report describes two cases of epidermoid tumor of the fourth ventricle diagnosed with metrizamide computed tomography. They both presented as a low-density lesion in the region of the fourth ventricle on computed tomography. They did not show any enhancement after intravenous injection of contrast medium and had no hydrocephalus. Metrizamide-enhanced computed tomography demonstrated the irregular fourth-ventricular filling defect characteristic of epidermoid tumors.

Epidermoid tumor in the fourth ventricle, with particular reference to metrizamide CT cisternography findings

The case of an epidermoid tumor in the fourth ventricle is presented, in which metrizamide computed tomographic (CT) cisternography was carried out. Unique features shown in the study might be specific to this lesion in this particular location. Clinical correlation of this finding was made with those findings seen at the operation.

Paramedian hourglass epidermoid extending above and below the tentorium

The case of a 22-year-old woman with a large hourglass epidermoid tumor extending both below and above the tentorium is presented. The tumor was located in the suprasellar region, left middle cranial fossa, and posterior fossa on the left side. Conventional computerized tomographic (CT) scanning was inconclusive as to the actual extension of the tumor, whereas air encephalography was more helpful. The subtemporal transtentorial approach made it possible to achieve a seemingly radical excision of the tumor. Nevertheless, the CT scan one year later showed the presence of a small tumor mass. The diagnostic and surgical implications are discussed in light of few similar cases reported in the literature.