Acute cerebellar infarction simulating posterior fossa tumor]

We report a case of space-occupying infarction of the left cerebellar hemisphere with occlusive hydrocephalus and left to right shift of the fourth ventricle. The patient, a 58 years old man, underwent shunting and decompressive craniectomy of the posterior fossa and survived without neurological deficits.     

Acute cerebellar hemorrhage and CT evidence of tight posterior fossa

We studied 14 patients with cerebellar hemorrhage and a tight posterior fossa, defined by the following CT criteria: effacement of the basal cisterns and ventricular enlargement consistent with obstructive hydrocephalus. In 10 patients, the fourth ventricle was not seen; in 4, it was enlarged and filled with blood. Six patients died before surgery, and eight were treated surgically. Six patients with cerebellar hemorrhage but no CT evidence of a tight posterior fossa survived without surgery.     

Delayed intraventricular tension pneumocephalus complicating posterior fossa surgery for cerebellar medulloblastoma

A child is described in whom intraventricular tension pneumocephalus developed 10 days after removal of a cerebellar medulloblastoma and 1 day after suture removal. The tension pneumocephalus was associated with hydrocephalus and CSF leakage from the suture line. The symptoms of the pneumocephalus were rapidly progressing loss of consciousness and hemiplegia which were promptly reversed upon aspiration of the intracranial air. A large amount of intraventricular air present in the immediate postoperative period was, however, clinically silent. The characteristics of this unusual presentation, its relation to asymptomatic pneumocephalus. hydrocephalus and the preventive and therapeutic measures required to deal with such conditions are discussed.     

后颅窝枕下减压术治疗大面积小脑梗死的预后分析

目的分析后颅窝枕下减压术治疗大面积小脑梗死的手术时机、手术方式及预后。 方法回顾性分析济南军区总医院神经外科自2010年1月至2018年2月符合纳入标准的大面积小脑梗死患者的临床资料。所有患者于CT及MRI检查确诊后24 h内行后颅窝枕下减压术,如有急性脑积水发生,先行脑室外引流术,再进行后颅窝枕下减压术。 结果本组患者12例,术前CT显示出现脑积水者4例,先行脑室穿刺外引流术,后行颅窝减压术。根据GOS评分评价患者外科治疗效果：良好7例,中残2例,重残1例,植物生存1例,死亡1例。 结论后颅窝减压术能避免大面积小脑梗死临床症状恶化进行性发展,改善预后。     

Transient cerebellar eye closure after posterior fossa surgery in a 5-year-old child

Introduction  Transient cerebellar eye closure (TCES) is a rare complication of cerebellar tumor surgery in children. The pathogenesis of this problem remains unclear, and controversy exists regarding whether it is a purely psychogenic disorder or an organic syndrome. The anatomical substrate for this transient eye closure remains unknown. Most of the cases reported were associated with the syndrome of mutism. Case report  We encountered a case of post-operative TCES in a 5-year-old girl with posterior fossa tumor. Results  We are presenting this rare complication with the hope of elucidating further on clinical course of illness and literature review on the possible pathophysiological mechanism.     

Diffusion tensor imaging of the superior cerebellar peduncle identifies patients with posterior fossa syndrome

Introduction

Posterior fossa tumors are the most common brain tumor of children. Aggressive resection correlates with long-term survival. A high incidence of posterior fossa syndrome (PFS), impairing the quality of life in many survivors, has been attributed to damage to bilateral dentate nucleus or to cerebellar output pathways. Using diffusion tensor imaging (DTI), we examined the involvement of the dentothalamic tracts, specifically the superior cerebellar peduncle (SCP), in patients with posterior fossa tumors and the association with PFS.

Methods

DTI studies were performed postoperatively in patients with midline (n?=?12), lateral cerebellar tumors (n?=?4), and controls. The location and visibility of the SCP were determined. The postoperative course was recorded, especially with regard to PFS, cranial nerve deficits, and oculomotor function.

Results

The SCP travels immediately adjacent to the lateral wall of the fourth ventricle and just medial to the middle cerebellar peduncle. Patients with midline tumors that still had observable SCP did not develop posterior fossa syndrome (N?=?7). SCPs were absent, on either preoperative (N?=?1, no postoperative study available) or postoperative studies (N?=?4), in the five patients who developed PFS. Oculomotor deficits of tracking were observed in patients independent of PFS or SCP involvement.

Conclusion

PFS can occur with bilateral injury to the outflow from dentate nuclei. In children with PFS, this may occur due to bilateral injury to the superior cerebellar peduncle. These tracts sit immediately adjacent to the wall of the ventricle and are highly vulnerable when an aggressive resection for these tumors is performed.     

Clinical and radiographic predictors of neurological outcome following posterior fossa decompression for spontaneous cerebellar hemorrhage

Spontaneous cerebellar hemorrhage often requires surgical suboccipital decompression and clot evacuation. Predictors of postoperative neurological deficits and outcome are not widely addressed in the literature. A retrospective review was conducted on 37 consecutive patients with the diagnosis of cerebellar hemorrhage requiring suboccipital decompression and clot evacuation. Clinical and radiographic variables were analyzed. Outcome measures were postoperative Glasgow Coma Scale (GCS) score, and long-term outcome measured by Rankin score and Glasgow Outcome Scale (GOS) score. A multivariate statistical analysis was conducted. The average age of patients was 71.1 years. There was significant improvement of neurological exam from a mean preoperative GCS score of 8.8 to a mean postoperative GCS score of 13.0. The mortality rate was 37.9%. According to the Rankin scale, 58.6% were functionally independent, 3.4% had a moderate disability, and none had a major disability or was in a vegetative state. Using GOS score, 62.1% had a favorable outcome. The presence of multiple comorbidities was associated with worse postoperative GCS and long-term outcome. A worse preoperative neurological exam, age older than 70 years, and the presence of intraventricular hemorrhage correlated only with a worse postoperative exam but not with the long-term outcome. Patients improve neurologically after posterior fossa decompression for cerebellar hemorrhage and a high percentage attain long-term functional outcome. Only the presence of multiple clinical comorbidities was associated with a worse outcome. Since there are no other preoperative predictors of long-term outcome, we recommend suboccipital decompression, when indicated, for patients with cerebellar hemorrhage regardless of age, hematoma size, or preoperative neurological exam.     

Traumatic posterior fossa hematoma

The traumatic posterior fossa hematoma was regarded as relatively rare thing, but recently, as the result of the prevalence of CT scanners, the number of reported cases is increasing. We report nine cases of traumatic posterior fossa hematoma. We divided into two categories: one was the acute epidural hematoma, the other was the acute subdural hematoma with cerebellar contusion. Five were cases of the acute epidural hematoma, three were cases of the acute subdural hematoma with cerebellar contusion and a case had both an epidural and a subdural hematoma. All the cases had struck the occipital region and had the occipital bone fracture. The prognosis of the five cases of the acute epidural hematoma was excellent, but that of the four cases of the acute subdural hematoma with cerebellar contusion was poor and they all died inspite of the removal of the hematoma executed in three cases. We estimated that the hitting forth was extremely strong in cases of the subdural hematoma with cerebellar contusion, and that the momentary deformity of the occipital bone might injure the cerebellum directly. Once a hematoma was produced in the posterior fossa, it oppresses the brainstem and causes the acute hydrocephalus, so the state of consciousness and respiration deteriorate suddenly. In cases of the acute epidural hematoma, appropriate surgical intervention could save the patients and resulted in good outcome. But in some cases of the fulminant type acute epidural hematoma of the posterior fossa caused by tearing the sinuses, though we have not experienced, patients die before the diagnosis and treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Giant posterior fossa teratoma

In this study we report a rare case of a giant midline posterior fossa teratoma; its clinical presentation, radiological appearance, treatment and outcome, with an extensive review of the literature. Received: 7 December 1998 Revised: 22 March 1999     

Familial posterior fossa arachnoid cyst

Background Arachnoid cysts are a relatively common incidental finding on CT scans of the brain. They most commonly occur in the middle cranial fossa, where familial occurrence has rarely been reported. Posterior fossa arachnoid cysts are more unusual.Case histories We report the presence of quadrigeminal cistern arachnoid cysts in siblings.     

Arachnoid cyst of the posterior fossa

Arachnoid cysts of the posterior fossa are uncommon. Our case of a 49-year-old man presented with a 2 month history of headaches, nausea, and vertigo associated with walking instability. An MRI revealed a median well-circumscribed cystic lesion of the posterior fossa, with similar signal characteristics to CSF, and without connection to the fourth ventricle. This aspect suggested either arachnoid or hydatid cysts. Direct open surgery was performed allowing complete removal of the cyst wall, with a good outcome.     

Ganglioglioneurocytoma of the posterior fossa.

OBJECTIVE AND IMPORTANCE: Ganglioglioneurocytoma is not yet a well defined clinical and histopathological entity; recent reports outline the histopathological features of this very rare trimorphous tumor, under different names with its basic components of gangliocytoma, neurocytoma and glioma. Four previous reports described this tumor in eleven patients. This is the first case report describing ganglioglioneurocytoma in the posterior fossa. CLINICAL PRESENTATION AND INTERVENTION: A 31-year old male with midline posterior fossa ganglioglioneurocytoma is described, providing the neuroimages and histopathological studies. CONCLUSION: Ganglioglioneurocytoma is a rare mixed neuronal and glial tumor that can also occur in the posterior fossa.     

Dermoid cyst of the posterior fossa

Intracranial dermoid tumors represent a rare clinical entity accounting for 0.1-0.7% of all intracranial tumors. Their location in the posterior fossa is uncommon. We report a 16-year-old male patient who presented with clinical signs of increased intracranial pressure and cerebellar symptoms. The CT scan revealed a median cystic lesion of the fourth ventricle causing an active triventicular hydrocephalus. The MRI showed a median well shaped cystic lesion, of low signal intensity compared to the CSF, with capsular contrast enhancement. He underwent endoscopic third ventriculostomy before subtotal removal of the lesion. The postoperative course was uneventful, and the histological diagnosis was a dermoid cyst. Through this observation, we aim to discuss the clinical, and radiological aspects of the posterior fossa dermoid cyst, and to review the therapeutic strategies.     

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.     

Congenital cavities of the posterior fossa

Summary Two cysts adjacent to the recessus lateralis, but without any connection with the latter, are described. The first was found at the autopsy of a female psychiatric patient of 54 years, who had died of a cerebrovascular accident. The second case, was that of a man 61 years old. The neurosurgeon, after performing bilateral trephination for an acute hydrocephalus had found, a cyst of the right tonsil of the cerebellum.The author supposes that in these cases parts of the original roof-plate had persisted latero-ventrally to the cerebellum. The cysts first described byKramer were also thought to originate from this tissue. Some other abnormal cavities and curious cerebellar defects are described in connection with these two cases.

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Zusammenfassung Zwei dem Recessus lateralis anliegende, mit diesem jedoch nicht verbundene Cysten werden beschrieben. Die erste fand sich autoptisch bei einer psychiatrischen Patientin von 54 Jahren, die an einem cerebrovasculären Zwischenfall starb. Im zweiten Fall, einem 61 jährigen Mann, hatte der Neurochirung bei bilateraler Trepanation wegen eines akuten Hydrocephalus eine Cyste der rechten Kleinhirntonsille gefunden.Der Verfasser vermutet, daß in diesen Fällen Teile der ursprünglichen Flügelplatte ventrolateral vom Kleinhirn persistierten. Die erstmals vonKramer beschriebenen Cysten wurden ebenso dieser Anlage zugeschrieben. In Verbindung mit diesen Beobachtungen werden einige andere abnorme Höhlen und merkwürdige Defekte des Kleinhirns beschrieben.