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.     

Spinal arachnoid cyst causing paraplegia following skull base surgery

A 40-year-old woman presented with a right petroclival meningioma compressing the brainstem and manifesting as a 6-month history of headache and gait difficulty. The patient underwent subtotal removal of the tumor via an anterior transpetrosal approach. The postoperative course was complicated by cerebrospinal fluid rhinorrhea, bacterial meningitis, and acute hemorrhagic rectal ulcer. The patient was discharged home in good condition after prolonged medical treatment. Four months after the surgery, the patient noted recurrence of gait difficulty. Magnetic resonance (MR) imaging of the brain showed enlargement of the ventricles and no residual brainstem compression. A ventriculoperitoneal shunt was placed, but the symptoms were unchanged. The shunt was removed 2 months later because of infection. The patient's gait gradually deteriorated, although repeat brain MR imaging showed no significant increase in ventricular size. Ten months after the initial surgery she became paraplegic. MR imaging of the thoracic spine revealed a large arachnoid cyst extending from C-6 to T-6. The patient underwent T2-4 laminectomy, partial removal of the cyst wall, and duraplasty, but no clinical improvement was observed. Preexisting long-tract signs and coincidental hydrocephalus confused the neurological findings and delayed detection of the spinal lesion in this case. Neurosurgeons should be alert to the possibilities of insidious spinal lesion if the patient has progressive neurological disorder which does not match the known cranial lesion.     

Glioblastoma multiforme occurring in a patient treated with gamma knife surgery. Case report and review of the literature

Stereotactic radiosurgery is being increasingly advocated as the primary modality for treatment of vestibular schwannomas (VS). This modality has been shown to arrest tumor growth, with few associated short-term morbidities, and with possibly better hearing and facial nerve preservation rates than microsurgery. Radiation-induced oncogenesis has long been recognized, although stereotactic radiosurgery de novo induction of a secondary tumor has never been clearly described. The authors report on a patient with a VS who did not have neurofibromatosis Type 2 and who underwent gamma knife surgery (GKS). This patient required microsurgical removal of the VS within 8 months because of development of a tumor cyst with associated brainstem compression and progressive hydrocephalus. The operation resulted in clinical stabilization and freedom from tumor recurrence. Seven and a half years after undergoing GKS, the patient presented with symptoms of raised intracranial pressure. Magnetic resonance imaging demonstrated a new ring-enhancing lesion in the inferior temporal lobe adjacent to the area of radiosurgery, which on craniotomy was confirmed to be a glioblastoma multiforme (GBM). Despite additional conventional external-beam radiation to the temporal lobe, the GBM has progressed. Whereas this first reported case of a GBM within the scatter field of GKS does not conclusively prove a direct causal link, it does fulfill all of Cahan's criteria for radiation-induced neoplasia, and demands increased vigilance for the potential long-term complications of stereotactic radiosurgery, and reporting of any similar cases.     

Tumefactive cyst with a vascular blush as a late complication after combined embolization and stereotactic radiosurgery treatments for a cerebral arteriovenous malformation

Summary Cyst formation is a recognized late complication after stereotactic radiosurgery for cerebral arteriovenous malformations (AVMs). We report on a patient with delayed cyst formation after combined embolization and stereotactic radiosurgery treatments for a cerebral AVM. The true nature of the cyst was complicated by tumefactive magnetic resonance MR imaging characteristics. The tumefactive cyst was associated with an additional imaging finding suggestive of a neoplastic lesion – a ‘blush’ on conventional angiography.     

Multiple complications from an intracranial epidermoid cyst: case report and literature review

Intracranial epidermoid and dermoid tumors are unusual benign lesions that are potentially curable. Subtotal removal carries a high incidence of recurrence, plus the rare possibility of carcinomatous degeneration of the remnants. Aseptic meningitis from spillage of cyst contents into the subarachnoid space is frequent after operation and has been reported to occur spontaneously. A case of a patient with a posterior fossa epidermoid cyst presenting with multiple bouts of aseptic meningitis in which squamous cell carcinoma arose in recurrent tumor 5 years after subtotal removal of the benign lesion is described.     

Stereotactic radiosurgery and vestibular schwannoma: hydrocephalus associated with the development of a secondary arachnoid cyst: a report of two cases and review of the literature

Stereotactic radiosurgery for vesibular schwannoma requires long-term follow-up with complete MR imaging. We report two cases of a large secondary arachnoid cyst developing in the cerebellopontine angle following stereotactic radiosurgery. In one case this was associated with progressive ventriculomegaly and the onset of symptomatic hydrocephalus requiring emergency treatment. The second patient had ventriculomegaly at diagnosis, but developed an arachnoid cyst following treatment. Although both arachnoid cysts and hydrocephalus may also occur spontaneously in patients with vestibular schwanomma, the incidence is higher after stereotactic radiosurgery. As both complications may be associated with sudden clinical deterioration, follow-up with full cranial T1 and T2 weighted MR imaging is required to reveal these complications, in addition to assessing tumour response.     

Dumbbell-shaped intradiploic epidermoid cyst involving the dura mater and cerebellum

A 55-year-old woman presented with an epidermoid cyst extending to the cerebellum manifesting as headaches and pain in the left eye. Magnetic resonance imaging showed an intradiploic part with ring enhancement and an intracerebellar part. Intraoperative inspection revealed erosion of the occipital bone and defective dura mater. The tumor was located both epidurally and subdurally and the cyst consisted of pearly white keratin. The tumor was totally removed and the patient was discharged with no neurological deficit. The intradiploic part of the tumor formed the body and the intracerebellar part was caused by inflammatory reaction, which resulted in the atypical enhancement of the intradiploic part.     

Stereotactic radiosurgery for well-circumscribed fibrillary grade II astrocytomas: an initial experience

OBJECTIVE: To examine the role of stereotactic radiosurgery in the management of patients with progressive, well-circumscribed grade II fibrillary astrocytomas. METHODS: During a 13-year interval, 12 patients (median age: 25 years) required multimodality management for recurrent or unresectable World Health Organization (WHO) grade II fibrillary astrocytomas. Tumors involved the brainstem (n = 4), thalamus (n = 1), cerebellum (n = 1), frontal lobe (n = 4), temporal lobe (n = 1), and parietal lobe (n = 1). Diagnosis was confirmed by stereotactic biopsy (n = 5), partial resection (n = 5), and near total resection (n = 2). Multimodality management of patients prior to radiosurgery included fractionated radiation therapy (n = 4), stereotactic cyst drainage (n = 1), and ventriculoperitoneal shunt placement (n = 2). Tumor volumes varied from 1.2 to 45.1 cm(3). The median radiosurgical dose to the tumor margin was 16 Gy. RESULTS: After radiosurgery, serial imaging showed complete tumor resolution in 1 patient, reduced tumor volume in 4, stable tumor volume in 3, and delayed tumor progression in 4 (3 patients with increase in cyst size only). Therapy after radiosurgery included additional cytoreductive surgery (n = 1) for recurrence of a higher grade tumor, stereotactic cyst aspiration (n = 1), and stereotactic intracavitary irradiation (n = 1). All patients were alive at a median follow-up of 52 months after radiosurgery and 103 months after diagnosis. In 8 patients, follow-up lasted more than 60 months. CONCLUSION: Stereotactic radiosurgery is a potential alternative or adjunctive strategy in the management of selected patients with WHO grade II fibrillary astrocytomas.     

脊髓内胆脂瘤的诊断和手术治疗

目的提高脊髓内胆脂瘤的诊断水平及选择治疗方法。方法总结１９７８～１９９５年收治的经手术和病理证实的１０例脊髓内胆脂瘤的经验。结果患者临床表现无特异性。本组ＣＴ检查８例，显示肿瘤呈现均匀低密度影像，边界清楚，强化扫描多无增强。ＭＲ检查４例，肿瘤呈现信号强度变化不定的特点，边界清楚。１０例患者均行手术治疗，肿瘤全切除１例，次全切除９例。８例术后得以随访，无复发。结论肿瘤全切是治疗本病的最好选择。     

Epidermoid cyst of the cerebellopontine angle. A surgical series of 10 cases and review of the literature

Epidermoid cyst or cholesteastoma is a congenital slow growing lesion. It usually arises in the paramedian cisterns of the posterior fossa. Its incidence varies between 0.2 and 1% of all intracranial tumors. The cerebello-pontine angle (CPA) is the most common localization. Our study reports 10 observations of CPA epidermoid cysts, treated in our department between 1989 and 1999. The age of our patients ranged from 20 to 45 years, with male predominance. The patients were admitted with symptoms of cerebello-pontine angle syndrome or signs of posterior fossa tumor. CT-scan was performed in all cases and MRI was performed in 5 patients. The audiometric explorations only provided an orienting contribution. Treatment was exclusively surgical. The retro-sigmoid approach was used in 6 cases, the sub-occipital in 30% and a subtemporal approach in one case. Total resection of the epidermoid cysts was accomplished in 4 cases, and subtotal resection in 4 cases. Two patients underwent partial resection and underwent a revision procedure. The histological examination showed an epidermoid cyst in all cases. The clinical course was controlled in 6 patients: 4 patients recovered and became symptom free. A persisting neurologic deficit was observed in two cases (hearing loss, dysphonia); 4 patients were lost to follow-up. Epidermoid cyst is a benign tumor. Total resection is the ideal treatment, but we have to be aware, taking into consideration the adherence of the tumor to neurovascular structures, of the risks at attempting total resection.     

Pseudocapsule formation after gamma knife radiosurgery for trigeminal neurinoma--case report--

A 38-year-old female presented with a trigeminal neurinoma manifesting as left facial paresthesia. The diagnosis was based on magnetic resonance (MR) imaging findings. Gamma knife radiosurgery (GKR) was performed at another hospital at her request. Fifteen months after the GKR, follow-up MR imaging revealed tumor regrowth causing extensive compression of the brainstem, and cyst formation in the tumor. Her clinical symptoms including facial pain and diplopia had worsened, so she was referred to our affiliated hospital for microsurgery. The tumor was totally resected, but the left trigeminal nerve had to be sacrificed because of pseudocapsule formation which covered both the tumor and the trigeminal nerve fibers. The diplopia disappeared, but her facial pain deteriorated after the operation. GKR can induce fibrosis or degenerative change in nearby structures, which may complicate subsequent surgery.     

Posterior fossa epidermoid cysts presenting with unusual radiological appearances--two case reports

Intracranial epidermoid cysts generally appear as hypodense on computed tomography (CT), hypointense on T(1)-weighted magnetic resonance (MR) imaging, and hyperintense on diffusion-weighted MR imaging. We report two cases of posterior fossa epidermoid cysts with unusual radiological features. A 49-year-old male presented with facial dysesthesia and a 12-year-old male presented with diplopia and internuclear ophthalmoplegia. CT of both cases revealed hyperdense lesions. MR imaging showed the first case as hypointense in the posterior part and hyperintense in the anterior part of the tumor on diffusion-weighted imaging, and the second case as hyperintense on diffusion-weighted and T(1)-weighted MR imaging. Surgical exploration revealed that the tumors consisted of creamy materials, instead of the usual semi-solid or flaky texture in epidermoid cysts. Xanthochromic serous fluid was also contained in the superoposterior half of the cyst of the first case. These unusual contents of the cyst may be responsible for the unusual neuroimaging findings. Histological examination showed both cysts were lined with stratified squamous epithelium and contained keratinaceous materials. Therefore, epidermoid cysts can occasionally present with unusual radiological characteristics giving rise to a diagnostic pitfall.     

Microsurgery for intradural epidermoid cyst at cauda equina level in a 9-year-old child: A case report

Introduction and importanceEpidermoid cysts are rare benign tumors. Here, we present a case of spontaneous intradural epidermoid cyst at cauda equina level in a 9-year-old patient, which we believed the first case to be reported in Vietnam.Case presentationA 9-year-old boy presented with 4 months of spontaneous left lower extremity muscle weakness and paresthesia. The MRI images suggested the diagnosis of intradural epidermoid cyst at cauda equina level. The patient underwent L5–S1 laminectomy and durotomy for tumor resection. The histology confirmed the diagnosis of epidermoid cyst. Post-operative images demonstrated total cyst removal.Clinical discussionThe epidermiology, presentation and diagnosis and strategy of treatments as well as their outcomes were discussed.ConclusionDiagnosis of spinal epidermoid cyst is often delayed for its obscure presentation. Microsurgical dissection along with intra-operative mobile C-Arms enable total tumor resection while preserving spinal stability and neurological function. Follow-up with post-operative magnetic resonance imaging and tumor marker are helpful.     

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

Summary 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.     

Stereotactic radiosurgery for pilocytic astrocytomas when multimodal therapy is necessary

OBJECT: The goal of this study was to examine the role of stereotactic radiosurgery in the treatment of patients with recurrent or unresectable pilocytic astrocytomas. METHODS: During a 13-year interval, 37 patients (median age 14 years) required multimodal treatment of recurrent or unresectable pilocytic astrocytomas. Tumors involved the brainstem in 18 patients, cerebellum in three, thalamus in five, temporal lobe in four, and parietal lobe in two, as well as the hypothalamus, optic tract, corpus callosum, insular cortex, and third ventricle in one patient each. Diagnosis was confirmed with the aid of stereotactic biopsy in 12 patients, open biopsy in five, partial resection in eight, and near-total resection in 12. Multimodal treatment included fractionated radiation therapy in 10 patients, stereotactic intracavitary irradiation of tumor in four, chemotherapy in two, cyst drainage in six, ventriculoperitoneal shunt placement in three, and additional cytoreductive surgery in four. Tumor volumes varied from 0.42 to 25 cm3. The median radiosurgical dose to the tumor margin was 15 Gy (range 9.6-22.5 Gy). After radiosurgery, serial imaging demonstrated complete tumor resolution in 10 patients, reduced tumor volume in eight, stable tumor volume in seven, and delayed tumor progression in 12. No procedure-related death was encountered. Thirty-three (89%) of 37 patients are alive at a median follow-up period of 28 months after radiosurgery and 59 months after diagnosis. Eight patients participated in follow-up review for more than 60 months. Three patients died of local tumor progression. CONCLUSIONS: Stereotactic radiosurgery is a valuable adjunctive strategy in the management of recurrent or unresectable pilocytic astrocytomas. Despite the favorable histological characteristics and prognosis usually associated with this neoplasm, an adverse location, recurrence, or progression of this disease requires alternative therapeutic approaches such as radiosurgery.     

Acquired lumbar epidermoid cyst in an adult

A 61-year-old female complained of low back pain, and had been treated by spinal anesthetic injection more than 70 times over 14 years. Magnetic resonance (MR) imaging, performed at the age of 47 years, revealed no abnormal lesion. However, she developed irritable hypesthetic pain in the left leg at 61 years of age. MR imaging revealed a round mass appearing isointense on the T1-weighted and slightly hyperintense on the T2-weighted images. Laminectomy revealed an epidermoid cyst, which was removed. This case clearly demonstrates that adults can acquire epidermoid tumor which very probably has an iatrogenic origin. The incidence of epidermoid tumor is low, but we should be aware of the potential adverse complications such as formation of epidermoid tumors after lumbar puncture.     

Primary intracranial squamous cell carcinoma--case report

A 50-year-old female presented with primary intracranial squamous cell carcinoma (SCC) at the right cerebellopontine angle manifesting as right facial nerve paresis. She had undergone gross total removal of a right cerebellopontine angle epidermoid cyst 10 years before and had done well until recently. Magnetic resonance imaging showed a heterogeneous tumor with markedly enhanced irregular margin. Subtotal removal of the tumor was achieved. Histological examination showed moderately differentiated SCC. After surgery, she underwent chemotherapy and gamma radiosurgery. She is now well 5 years after the diagnosis of SCC.     

Giant extradural epidermoid cyst of the posterior fossa

We report an unusual case of giant extradural epidermoid cyst of the posterior fossa in a 73-year-old man. The patient presented headache and gait disturbance for 3-4 months, cerebellar ataxia, left cerebellar dysmetria, and perturbed balance. The CT-scan showed a huge posterior fossa extradural lesion with a small area of peripheral contrast enhancement. Outcome was good after total resection of the lesion via a suboccipital approach. Pathology reported an epidermoid cyst. Extradural epidermoid cyst is a rare benign tumor of the skull which sometimes can reach considerable size. It is a slow growing lesion and may cause mild neurological deficits. The goal of surgical treatment is total resection of the tumor with its capsule. The long-term prognosis is excellent after successful resection.