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.     

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.     

Osteoplastic lateral suboccipital approach for acoustic neuroma surgery

OBJECTIVE: Persistent headache remains a significant problem in a small group of patients after acoustic neuroma surgery via the lateral suboccipital approach. We describe a modified technique of osteoplastic lateral suboccipital craniotomy for surgery of the cerebellopontine angle. This simple and elegant technique provides a superior cosmetic result and a significant reduction in patients' symptoms. METHODS: We report on our series of 75 patients who underwent surgery for acoustic neuroma. The maximal follow-up period was 4 years. RESULTS: No patients reported headache postoperatively. Cerebrospinal fluid fistulae were not observed. CONCLUSION: This modified approach minimizes cerebellar retraction, and the neural and vascular structures can be preserved under direct visualization of the tumor. This lateral suboccipital approach is a useful modification of previous approaches in acoustic neuroma surgery. It provides successful tumor resection and excellent functional results.     

An extended middle fossa approach combined with a suboccipital craniectomy to the base of the skull in the posterior fossa

A new approach to the base of the skull in the posterior fossa is described. This approach involves removing the petrous bone without any injury to the labyrinth, and dividing the superior petrosal sinus and tentorium cerebelli. A combined suboccipital craniectomy is used for excision of the portion of tumors that extended inferiorly. Total or subtotal removal of tumors was performed in 11 patients and partial removal in 3 patients, without any operative mortality. The facial nerve was preserved in all patients and hearing was retained in 9 of 12 patients. This approach is useful for large tumors located around the clivus.     

远外侧枕下入路临床应用的初步经验

目的 改良远外侧枕下入路,适当显露病变,改善延髓和上颈髓腹侧病变的治疗效果。方法 采用远外侧枕下入路的5种改良入路,包括经小关节入路、经枕骨髁后入路、部分经枕骨髁入路、完全经枕骨髁入路和极端外侧经颈静脉孔入路,治疗延髓及上颈髓腹侧和腹外侧肿瘤12例、椎动脉动脉瘤2例,并分析手术治疗的效果和并发症。结果 本组12例肿瘤患者,7例肿瘤全切除,5例肿瘤在部分切除,所有患者术后恢复良好;其中3例术后遗留永久性组颅神经麻痹。2例动脉瘤患者,1例夹闭瘤颈,1例动脉瘤切除的患者因脑干缺血死亡。没有与入路有关的严重并发症。结论 远外侧枕下入路的改良可以满足延髓及上颈髓腹侧和腹外侧病变手术的需要和良好手术野显著,减少不必要的手术步骤,改善治疗效果。     

An unusual middle fossa interdural epidermoid tumor. Case report.

The authors report an unusual case of an intracranial, interdural epidermoid tumor and cyst in a 72-year-old woman who presented with longstanding, mild numbness over her right cheek. She was initially treated conservatively, but on follow-up review the mass was found to have grown and evidence of hemorrhage was present, and therefore a subtotal resection was performed. This case should probably be classified as a paratrigeminal, interdural epidermoid cyst; this is the first known report in which magnetic resonance and computerized tomography images of such an entity are presented and discussed.     

Subtemporal-preauricular infratemporal fossa approach to large lateral and posterior cranial base neoplasms

A subtemporal-preauricular infratemporal fossa approach to remove 22 large neoplasms involving the lateral and posterior cranial base is detailed. The areas from which a neoplasm could be removed by this approach included the sphenoid and clival bone; the medial half of the petrous temporal bone; the infratemporal fossa; the nasopharynx; the retro- and parapharyngeal area; the ethmoid, sphenoid, and maxillary sinuses; and the intradural clivus-foramen magnum area. The pathology of the neoplasms included benign tumors such as meningioma, malignant cartilaginous neoplasms such as chordoma, and other malignant lesions such as nasopharyngeal carcinoma. This approach offers many advantages over other anterior and lateral approaches to the lateral and posterior cranial base: these include minimal brain retraction; direct access to the ipsilateral petrous and upper cervical internal carotid artery; reconstruction of extensive cranial base defects, often with the use of a vascularized rectus abdominus flap; preservation of the hearing conduction mechanism when it is not involved by tumor; and the maintenance of excellent facial nerve function postoperatively. The use of an anterior extradural approach (transethmoidal) and of an intradural approach (frontotemporal or retromastoid), either concurrently or separately, is necessary in some patients to effect total tumor removal. The most serious complication in this series was the death of a patient due to postoperative infection and bilateral carotid artery rupture, which may have been avoided by the use of a rectus abdominis muscle flap for reconstruction. Among the 21 surviving patients, 18 had a good outcome, two had a fair outcome, and one with preexisting neurological deficits had a poor outcome. One of the surviving patients with a chordoma died of pulmonary metastases 1 year later, without evidence of local recurrence. The length of postoperative follow-up evaluation in these patients is insufficient to make any judgment about the effectiveness of this surgical approach in achieving a cure or long-term control of the tumors described.     

Acute posterior fossa syndrome following lumbar drainage for treatment of suboccipital pseudomeningocele. Report of three cases

The authors report on a series of patients who underwent lumbar drainage of cerebrospinal fluid (CSF) for treatment of posterior fossa pseudomeningoceles and who subsequently developed an acute posterior fossa syndrome. These patients were found to have similar radiological findings demonstrating acute mass effect secondary to movement of CSF from the pseudomeningocele into the cerebellar parenchyma. Discontinuation of lumbar drainage resulted in symptomatic and radiological improvement in all patients. From these cases the authors infer that not all pseudomeningoceles communicate directly with the subarachnoid space. A readily recognizable appearance on magnetic resonance imaging that is useful in diagnosing this reversible complication of treatment for posterior fossa pseudomeningocele is also illustrated.     

Midline posterior fossa teratoma--case report

A 20-day-old female neonate presented with an immature teratoma in the midline posterior fossa. The tumor was totally removed but the patient died of pneumonia. Teratoma is a rare tumor, but very difficult to treat as the patients tend to be young, and the outcome is very poor.     

Spinal extradural arachnoid cyst--case report.

A 48-year-old male presented with progressive leg weakness. Magnetic resonance imaging and computed tomography myelography showed an extradural arachnoid cyst extending from the T-12 to L-2 levels in the thoracolumbar region. The cyst was confirmed at surgery and completely removed. This surgical intervention achieved improvement in the neurological symptoms.     

Cerebral alveolar hydatid cyst--case report.

A rare case of cerebral alveolar hydatid disease in a 41-year-old female is presented. The larval mass was subtotally removed and the presence of alveolar hydatid cysts established histologically. Postoperatively, slight mental disturbance persisted but paresis did not develop.     

Computed tomography-guided stereotactic aspiration of posterior fossa hematomas: a supine lateral retromastoid approach

We report a supine lateral retromastoid approach for computed tomography-guided stereotactic aspiration of hematomas of the posterior fossa. The method involves horizontal insertion of the aspiration needle at the suboccipital region with the patient in a supine position with the head turned 30 to 40 degrees away from the lesion and with slight forward flexion of the neck. Eleven hematomas have been removed through this approach thus far, nine cerebellar and two pontine. With this technique, general anesthesia is not needed and operative invasion is minimal, allowing hematoma aspiration in patients in whom operation would previously not have been indicated. An additional merit is the suitability of this method for elderly patients.     

Postoperative headache after the lateral suboccipital approach: craniotomy versus craniectomy.

The lateral suboccipital approach to the cerebellopontine angle is typically performed as a small craniectomy. Incisional pain and headache following cerebellopontine angle surgery have been reported. Adherence of the cervical muscles to the dura, which is richly innervated, with consequent traction has been suggested to be responsible for postoperative headache. Therefore, postoperative headache probably could be reduced by replacing the bone flap between the muscles and the dura. In a prospective non-randomized study this hypothesis was tested by comparing craniectomy and craniotomy. 40 patients underwent removal of an acoustic neuroma via the retrosigmoid approach. Patients with a history of migraine, with additional intracerebral tumors or recurrencies as well as patients who developed a CSF fistula postoperatively were excluded. 29 patients were eligible for further evaluation. 13 patients underwent a craniotomy, 16 patients a craniectomy. All patients were subject to a standardized telephone interview three months and one year after surgery. Comparing the craniotomy group to the craniectomy group no difference was observed regarding age, sex, tumor size and duration of operation. 3 months as well as 12 months postoperatively headache was significantly (p < 0.05) less frequent in the craniotomy group as compared to the craniectomy group. In conclusion, an osteoplastic craniotomy significantly reduces postoperative headache and is therefore highly recommended.     

Neuroepithelial cysts of the posterior fossa. Case report

The authors report the case of a patient harboring a posterior fossa neuroepithelial cyst who presented with positional facial weakness and syncope. The patient recovered rapidly after cyst fenestration and placement of an internal cyst-cisternal shunt. The pathogenesis and principles of diagnosis and management of these rare lesions are reviewed.     

Leptomeningeal cyst of the posterior fossa. Case report

A patient with a posttraumatic leptomeningeal cyst is described. The cyst simulated an occipital encephalocele and communicated with an epidural cerebrospinal fluid collection in the posterior fossa.