Epidermoid and dermoid cysts. Clinical evaluation and late surgical results

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.

Abscedation of posterior fossa dermoid cysts

Dermoid cysts of the posterior fossa are uncommon. When associated with a dermal sinus, these cysts are often diagnosed during early childhood. The main risk of such an association is contamination of the cyst leading to abscedation of the dermoid itself or formation of daughter abscesses within the cerebellar hemisphere. We recently treated a 20-month-old girl who had a congenital dermal sinus leading to an intradural dermoid cyst. In addition to the midline dermoid cyst, computerized tomography revealed an enhancing lesion extending into the adjacent left cerebellar hemisphere. Suboccipital craniectomy was undertaken after 2 days of external ventricular drainage, and the infected dermoid and adjacent cerebellar abscess were excised. Cultures of the operative specimen revealed Corynobacterium aquaticum, Enterobacter sakazakii and Enterobacter cloacae, requiring 6 weeks of intravenous antibiotic therapy consisting of ceftriaxone, penicillin and gentamicin. A diligent literature search revealed only 24 sporadic cases reported over a period of 56 years. All 24 cases were in children (mean age 17 months), and one-third were in infants under the age of 1 year. All but 1 of these patients underwent posterior fossa surgery, with mortality and morbidity rates of 13% and 10%, respectively. Eleven (40%) children had suppuration within the cerebellar parenchyma, while the rest had abscedation of the dermoid cyst alone. Among the cases reviewed S. aureus was the most common agent, occurring with a probability of 64%. Key issues for appropriate management of these benign lesions are discussed.

Dermoid cyst within an upper thoracic meningocele

A case of dermoid cyst within an upper thoracic meningocele is reported. The incidental feature of this combination is extremely rare. As upper thoracic meningocele is often associated with other spinal and intracranial abnormalities, close observation and radiologic evaluation of the craniospinal axis are necessary to obtain an exact diagnosis and to achieve an appropriate treatment.

The long history of a cerebello-pontine angle epidermoid tumour--a case report and lessons learned

The authors present the case of a patient accurately diagnosed and operated on for an epidermoid cyst in the CPA region, 30 years after the clinical onset with the initial symptom of hypoacusis. At the time of the operation, the patient presented with advanced CPA syndrome, and the tumour had grown to an enormous size. Complete capsule removal was not attempted due to its tenacious adherence to vital neurovascular structures. Thirteen years after surgery, the patient underwent a second operation due to tumour regrowth. The case provides supporting evidence that the clinical findings of a CPA epidermoid cyst may be minimal, and remain so for extended periods of time until the tumour has spread widely. Epidermoids tend to insinuate in the cisterns around cranial nerves, blood vessels, and the brainstem, rather than compressing these structures. The importance of early detection and radical removal, presently facilitated by Magnetic Resonance Imaging, is emphasized.

Surgical treatment of epidermoid cysts of the cerebellopontine angle

A total of 40 patients with epidermoid cysts of the cerebellopontine angle (CPA) underwent surgery between 1980 and 1993. Total resection was achieved in 30 cases (75%); in 10 cases (25%) parts of the cyst capsule were left because they adhered to the brainstem and vascular structures of the CPA. One patient with very large bilateral epidermoid cysts, who underwent complete bilateral resection in one stage, died of pulmonary aspiration and infection. As of their latest clinical and radiological follow-up examinations (mean 5.7 years), 93% of the patients are able to lead useful lives. Three cases of cyst regrowth have been observed thus far. Modern radiological tools and microsurgery techniques have considerably improved the completeness of cyst resection and reduced postoperative mortality and morbidity rates; however, there still are some cases in which complete resection is impossible without producing severe neurological deficits.

Cerebellopontine angle epidermoids: results of surgical treatment

Epidermoids, or congenital cholesteatomas, constitute about 0.2% to 1.5% of intracranial tumors, and 3% to 5% of tumors of the cerebellopontine angle (CPA). We review the surgical management of CPA epidermoids in 13 patients at the House Ear Clinic for the years 1978 to 1993. There were seven male and six female patients, ranging in age from 27 to 59 years (average, 40 years). Tumors ranged in size from 3.5 cm to 7.0 cm, and the surgical approach was tailored to the tumor extent and location. All patients complained at presentation of unilateral hearing loss, and nine had poor speech discrimination (less than 50%) preoperatively. Serviceable hearing was preserved in two patients. Two patients presented with facial nerve symptoms, and four cases had postoperative permanent facial nerve paralysis (House-Brackmann Grade V or VI). There were no surgical deaths. Four patients required second surgeries to remove residual cholesteatoma. Compared with prior series, we describe a higher rate of total tumor removed, as well as a higher rate of second operations, indicating a more aggressive approach to these lesions.

Epidermoid cyst of the brain stem. Case report

Brain stem epidermoid cysts are extremely rare lesions. Only nine cases have been reported. Management of the epidermoid cyst is decompression of cyst contents and removal of cyst capsule. But in some cases resection of the cyst may result in a poor outcome because of cyst wall adhesion into the brain stem.

Epidermoid tumors of the fourth ventricle

BACKGROUND

Epidermoids of the brain are rare tumors. Their fourth ventricle localization is about the rarest localization. No series of such tumors has been reported. Their manifestations and management are therefore not well understood.

METHODS

Four epidermoid tumors of the fourth ventricle were collected over a period of 39 years from the neurosurgical units of the American University of Beirut Medical Center and the Orient Hospital. These were retrospectively studied and the medical literature reviewed.

RESULTS

Epidermoids of the brain form 1% of all brain tumors, and those located in the fourth ventricle are 16.7% of the epidermoids. They rarely present symptoms of increased intracranial pressure. They commonly present in adults with only cerebellar signs. The duration of symptoms may be short, medium, or long. The diagnosis, when clinically suspected, should be confirmed by magnetic resonance imaging. An early diagnosis is the key for a good outcome.

CONCLUSION

Although a rare condition, these tumors can be lethal if not treated. Total excision should be attempted. Because this tumor is very slow-growing, a near-total excision is acceptable in cases where complete removal may endanger function or life.

Epithelial cystic lesions of the sellar and parasellar region: a continuum of ectodermal derivatives?

Cystic epithelial lesions of the sellar and parasellar region are classified on the basis of histology and location into Rathke's cleft cysts, epithelial cysts, epidermoid cysts, dermoid cysts, and craniopharyngiomas. A retrospective review of the clinical presentation, radiological findings, and histology was performed on 19 such lesions, and a survey of the literature pertinent to the classification, clinical presentation, and embryology of these lesions was conducted. Presentation was nonspecific and not predictive of histology. Imaging studies were generally useful in distinguishing these tumors, with the exception of Rathke's cleft cysts, suprasellar epidermoid cysts, and craniopharyngiomas, which frequently could not be differentiated. On microscopic examination, most lesions fit into distinct categories; however, overlap was common among all and some could not be definitively categorized by histological criteria. Evidence supportive of an ectodermal ancestry for sellar and parasellar epithelial-lined cystic lesions is presented. Based on the current findings and a review of the literature, it is suggested that these lesions represent a continuum of ectodermally derived cystic epithelial lesions.

Craniocerebral epidermoid and dermoid tumours: a review of 32 cases

We reviewed 22 epidermoid and 10 dermoid tumours of the skull and brain from patients operated on consecutively at Henry Ford Hospital between 1975 and 1991. There were 19 intradural (16 epidermoid, 3 dermoid) and 13 extradural (6 epidermoid, 7 dermoid) lesions. The average age at presentation was 35 years for patients with epidermoids and 15 years for those with dermoids. Common clinical presentations for patients with intradural lesions included headache, visual deficits, and seizures, whereas patients with extradural lesions harbored asymptomatic scalp masses. All patients with intradural lesions were investigated with computed tomography (CT) and cerebral angiography, and 8 patients underwent magnetic resonance imaging (MRI). Total resection was possible in 12 (92%) of 13 extradural tumours, all with excellent outcomes. Eight (42%) of the intradural tumours were completely resected. Overall, with the intradural tumours we had good to excellent results in 17 patients (90%), poor results in 1 (5%), and 1 death (5%). Re-operation was needed in 5 intradural recurrences (26%) with deterioration in only one patient's neurologic status postoperatively. From a review of ours and others' data, we conclude that 1) these tumours have an insidious onset despite significant size and mass effect as demonstrated by imaging studies; 2) CT, angiography, and particularly MRI help to define the extent of subarachnoid tumour spread and involvement of neurovascular structures, thus permitting better surgical planning; 3) a significant number of intradural tumours are difficult to excise because of their adherence to neurovascular structures, and thus are related to higher morbidity and mortality; and 4) because of extremely slow growth, complete tumour resection should not be the goal at the risk of injury to neurovascular structures.

Signal intensity patterns in intraspinal dermoids and epidermoids on MR imaging

Retrospective evaluation of MR images of nine intraspinal dermoid (n = 4) and epidermoid (n = 5) tumours was undertaken. T1-weighted images were available in all the patients while proton density (PD) and T2-weighted images were available in seven patients. Except for one lesion (only T1-weighted images were available in this case), all the lesions were clearly delineated on MR images. Most (5 out of 7) were better appreciated on T1- and PD-weighted images than on T2-weighted images. On T1-weighted images, the epidermoids were either iso- to mildly hypointense to the cord (n = 3), isointense to CSF (n = 1) or markedly hyperintense (n = 1). On the PD images, the epidermoids were either isointense to cord (n = 3) or markedly hyperintense (n = 1). All the lesions were iso- to hyperintense to CSF on T2-weighted images. Of the four dermoids three showed a mixed intensity pattern on all sequences; the dominant component gave short T1 and short T2 values, consistent with fat. The fourth lesion showed homogenous material with a signal intensity intermediate between that of CSF and cord on T1-weighted images. Dermal sinus tracts were present in four of the nine patients; three patients had an intraspinal component. This study shows that although MR imaging is excellent for their detection, it cannot differentiate the two tumour types.

Posterior fossa dermoid cyst associated with dermal fistula: report of 2 cases and review of the literature

Two cases of dermoid cysts of the posterior fossa in association with a dermal fistula and with different clinical presentations are reported. The patient in case 1 is a 14-month-old girl with a history of recurrent bacterial meningitis. Case 2, a 7-year-old girl, presented with a skin "granuloma" at the inion. Both cases, and a review of the literature, demonstrate the need for a thorough exploration of the cranial and spinal midline skin areas in every newborn and argue for widespread use of nuclear magnetic resonance imaging whenever a suspected midline lesion is found.

Massive bifrontal epidermoid tumor

There have been 27 cases of epidermoid tumor reported to arise from the frontal or ethmoid sinus area. We report the case of a virtually asymptomatic massive bifrontal epidermoid tumor arising from the ethmoid sinus in a 76-year-old male.

Spinal epidermoid cyst and cauda equina syndrome in a teenage girl

A sixteen year old girl presented with a four year history of hip pain followed subsequently by back pain radiating down her left leg, progressive urgency of micturition, urinary incontinence, a feeling of bladder fullness and incomplete bladder emptying, faecal impaction and finally, numbness in both of her buttocks. A diagnosis of Cauda Equina Syndrome was suspected on the history and the clinical examination. A plain X-ray of her lumbar spine revealed evidence of a slow growing mass within the vertebral canal at the level of L3. A Magnetic Resonance Imaging (MRI) scan confirmed an intradural space occupying lesion at the same level. This lesion was surgically removed and histological examination revealed a benign epidermoid cyst.

Proliferative assessment of craniopharyngioma and epidermoid by nucleolar organizer region staining

The histologic distinction between craniopharyngioma and epidermoid is equivocal. Eight craniopharyngiomas and ten epidermoids (including three dermoids) as well as nine rat (Wistar) abdominal skins that acted as control were investigated by a silver colloid method for nucleolar organizer regions (Ag-NORs). The mean number of Ag-NORs in at least 200 cells of both basal (columnar) epithelial cells and suprabasal (prickle) cells was evaluated. It was found that the mean number of Ag-NORs in basal cells of epidermoid and rat skin was significantly greater than that in suprabasal cells (P < 0.001 in nine of ten epidermoids and in all rat skins). On the other hand, of eight craniopharyngiomas, the mean Ag-NOR number in basal cells was not significantly different from that in suprabasal cells in five cases, and, further, the former was significantly smaller than the latter in the other three cases (P < 0.01 in two and P < 0.05 in one). These findings suggest that a stepwise maturation of the epithelial cells like that in mammalian skin epidermis exists in epidermoids but not in craniopharyngiomas. In craniopharyngiomas, the maturation of the epithelial cells seems to be considerably limited or lost from the aspect of proliferative potential as assessed by Ag-NOR score, which indicates neoplastic growth of craniopharyngiomas. Ag-NOR staining may thus be a useful method to distinguish craniopharyngioma from epidermoid.

Intracranial dermoid cysts with nasal dermal sinuses

Dermal sinuses penetrating the dura are important in that they may be complicated by C.N.S. infection, and this complication can be prevented by early surgery. Although well recognised over the occiput and lumbar spine, nasal dermal sinuses extending intracranially are much rarer and have received little attention in the neurosurgical literature. Two unique cases are presented, together with a literature review, discussing the anatomy, radiology, and management of the condition.

Ruptured dermoid tumor of the cavernous sinus associated with the syndrome of fat embolism. Case report

The syndrome of fat embolism is a well-known clinicopathological entity that may appear 2 to 4 days after skeletal trauma; nontraumatic causes have been recognized, however. This report details the fat embolism syndrome occurring in a patient after surgery within the cavernous sinus to remove a dermoid tumor.

Epidermoid cysts of the cranial bones

Ectodermally derived tissue in ectopic sites is seen in the head and neck. Extracranial dermoid and epidermoid tumors are relatively rare. While most otolaryngologists are familiar with the cholesteatoma of the otic area, not very many are exposed to this lesion in other sites. Those of the cranial bones are even rarer still. These tumors may expand (1) laterally in the cranial bones, (2) externally to present as masses in the scalp or facial region, or (3) internally to involve the intracranial contents. A patient with a frontal bone epidermoid, whose tumor had expanded in all three directions to erode both inner and outer cortex of cranium and laterally to rupture into the frontal sinus, is discussed. The literature is reviewed and the management of these rare masses is discussed.

Painful tic convulsif caused by a brain tumor: case report and review of the literature

Patient with painful tic convulsif caused by a brain tumor is presented. The patient was admitted with right trigeminal neuralgia and ipsilateral facial spasm, i.e., painful tic convulsif. Preoperative computed tomography scans showed no apparent abnormalities; however, surgery revealed that these symptoms were associated with a pearly tumor located in the cerebellopontine angle. Subtotal resection for the decompression of the right trigeminal and facial nerves was performed and resulted in complete relief of the symptoms. Histological examination demonstrated the tumor to be an epidermoid cyst.

Intramedullary epidermoid cysts of the spinal cord. Case report

Epidermoid cysts are tumors familiar to neurosurgeons, but intramedullary epidermoid cysts are rare. The authors report the case of a 6-year-old girl presenting with progressive paraparesis. A midthoracic intramedullary mass was revealed on myelography and magnetic resonance (MR) imaging and confirmed as an intramedullary epidermoid cyst at surgery, at which time the cyst was removed. This is the fourth report documenting a purely intramedullary epidermoid cyst occurring in a child. The pathology and etiology, epidemiology, clinical features, radiology (including MR image characteristics), and surgical treatment of such rare intramedullary benign tumors are discussed. Magnetic resonance imaging reduces the delay in diagnosis of spinal cord tumors but should be guided by clinical judgment.

Non-acoustic tumors of the cerebellopontine angle

52 patients with non-acoustic neurinoma tumors of the cerebellopontine angle undergoing surgery over a 16 year period (1974-1989) are analyzed with regard to epidemiologic factors, presenting symptoms, neurological findings, diagnostic procedures, surgical approaches, recurrences, and longterm survival rates. Meningiomas (20 cases) and epidermoid tumors (16 cases) outnumber the rare tumors which exhibit wide histological variation. Trigeminal neuralgia was found as a significantly frequent sign of epidermoids. Total removal was possible in nine meningiomas (45%), fourteen epidermoid tumors (87.5%) and 11 (69%) mostly malignant rare tumors. There were many longterm survivors in meningioma and epidermoid groups with a median follow-up period of 4.1 years. The results are compared to those reported in the literature and a brief review of reported rare tumors of the angle is presented.

Dermoid and epidermoid cysts of the midline in the posterior cranial fossa

Clinical features and surgical outcome of 16 patients with dermoid or epidermoid cysts on the midline of the posterior cranial fossa are compared. Salient points in the comparison are the younger age, presence of associated malformations and better prognosis of dermoid cyst.

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.

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).

Supratentorial dermoid cysts

Supratentorial dermoid cysts are rare lesions. In eight cases presented here, the lack of recurrence after subtotal removal of the capsule and the good long-term prognosis are emphasized. This finding is in agreement with the literature. The frequent relationship of these lesions with the cavernous sinus suggests a vascular genesis in the development of intracranial dermoid cysts.

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.

Misinterpretation of neuroradiological appearances of an epidermoid cyst

Images

Epidermoid cysts of the brain stem. Report of three cases

The authors report the cases of three patients with epidermoid cysts which insinuated themselves into the brain stem. In all three patients, the tumor occupied the pons, although in one it was predominantly located in the medulla. The cyst contents and nonadherent tumor capsule were removed in all three patients, but no attempt was made to remove tumor densely adherent to the brain stem. One patient's cyst was removed in one operation, but maximal resection in the other two required two operations. After surgery, sixth nerve function completely returned in one patient; another patient had a stable pontine gaze palsy but developed new facial weakness; and the third patient had stable cranial nerve deficits with a diminished hemiparesis. The last patient developed a pseudomeningocele and communicating hydrocephalus, and required a lumboperitoneal shunt. In all three patients, computerized tomography scans demonstrated hypodense tumors not enhanced by contrast material. Magnetic resonance imaging was performed on two patients; in both, the tumors showed increased signal intensity relative to brain on T1-weighted images and decreased signal intensity relative to brain on T2-weighted studies. Magnetic resonance imaging, the most accurate modality for localizing these lesions and determining their extent, was also invaluable for postoperative monitoring and follow-up evaluation. Safe and adequate resection includes decompression of cyst contents and removal of nonadherent portions of the cyst capsule. Cyst wall adherent to the brain stem, however, should not be removed.

Long-term results of surgical treatment of cerebello-pontine angle epidermoids

The long term surgical results in a series of 17 epidermoids of the cerebello-pontine angle are reported. In 11 cases the capsule was removed subtotally and in 6 totally. The absence of mortality among the patients who underwent subtotal removal and the onset of recurrences, if any, only long after the first operation, justify subtotal removal when tight capsular adhesions are present.

Cranial and spinal tumors with meningitic onset

We review the literature on cases of cranial or spinal tumor presenting with meningitic symptoms. Embryonal tumors-dermoid cysts, epidermoid cysts, craniopharyngiomas, teratomas-and malignant gliomas were the cause of most of the episodes of chemical meningitis, single or multiple in patients with no neurological symptoms. Differential diagnosis from aseptic meningitis, especially from Mollaret aseptic meningitis, is essential.

Intradiploic epidermoid cysts of the skull: report of 10 cases and review of the literature

Intradiploic epidermoid cysts, fairly uncommon lesions in neurosurgical practice, are, as a rule, benign and slow-growing. Some attain great size, producing major neurological signs. Correct radiological assessment and complete removal of the tumour and its capsule are essential for adequate surgical treatment and good long-term prognosis. We report ten cases of intradiploic epidermoid cysts of the skull, three of which were giant lesions and one malignant, and analyze the clinicopathological and radiological features and treatment of these lesions in the light of the most important published data.

Dermoid cyst of the scalp: intracranial extension

Intracranial dermoids are rare and are usually associated with cutaneous scalp lesions. Five hundred forty-two scalp lesions were treated in a 22-year period, and were associated with intracranial lesions in three cases. High-risk cases can be identified by clinical and radiological features, confirmed by a computed tomography scan, and then referred for neurosurgical treatment.

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.

Iatrogenic cholesteatoma of the neck

Epidermal cysts of the upper neck may appear years after ipsilateral radical mastoidectomy for cholesteatoma. Three patients are presented, and the etiological factors operating in the development of such tumors in these patients and others cited in the literature are discussed.

Craniocerebral epidermoids and dermoids. A review of 44 cases

We review 40 epidermoids and 4 dermoids of the skull and brain treated surgically in our Department between 1976 and 1987. Fourteen were extradural and 30 intradural. The mean duration of symptoms was 3 years for extradural and 10 years for intradural tumours. Symptoms varied with tumour site, in some sites being helpful in differential diagnosis. Skull X-rays and CT were the key diagnostic investigations in extradural and CT in intradural lesions, the latter, with few exceptions, presenting a characteristic CT scan. In 7 cases MRI supplied important details on the tumour boundaries. All the diploic and orbital lesions were removed totally, with a good outcome. Twelve of the intradural lesions were removed totally, 9 subtotally and 9 partially, with a good outcome in 21 patients and a poor outcome in 4; 5 patients died. Outcome was unrelated to degree of removal.

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.

Intraspinal epidermoid and dermoid cysts. Surgical results of seven cases

Seven cases of intraspinal inclusion cysts, surgically treated between 1970 and 1984, are reported in this paper. Four were epidermoid cysts and three dermoid. Two cysts were located in the thoracic spine (one dermoid and one epidermoid) and five in the lumbosacral region (three epidermoid and two dermoid). Associated spinal dysraphia was noted in five cases. Congenital dermal sinus was found in two cases, spina bifida cystica in one, spina bifida occulta in one, and diastematomyelia in one case. The average postoperative follow-up period was 5 years. No neurological symptoms were found in the five patients who received early surgical treatment, but for the two patients whose operations were late, there were some residual neurological deficits. Therefore, early and accurate diagnosis and radical surgical extirpation are emphasized.

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.

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.