Cerebellar infarct caused by spontaneous thrombosis of a developmental venous anomaly of the posterior fossa. (1/258)

Spontaneous thrombosis of a posterior fossa developmental venous anomaly (DVA) caused a nonhemorrhagic cerebellar infarct in a 31-year-old man who also harbored a midbrain cavernous angioma. DVA thrombosis was well depicted on CT and MR studies and was proved at angiography by the demonstration of an endoluminal clot.  (+info)

Abnormal prenatal sonographic findings in the posterior cranial fossa: a case of Joubert's syndrome. (2/258)

Joubert's syndrome is a well-documented but rare disorder characterized by a variable combination of central nervous system, respiratory, renal and eye anomalies. The most significant and constant neuropathological finding is partial or complete agenesis of the cerebellar vermis. The syndrome was first described by Joubert and colleagues as a familial agenesis of the cerebellar vermis and appears to be inherited as an autosomal recessive trait. A case of Joubert's syndrome is described in which second-trimester ultrasonography demonstrated abnormal findings in the fetal posterior fossa with associated renal abnormalities. However, postnatal sonography of the posterior fossa could not confirm the prenatal findings, and the diagnosis of Joubert's syndrome was only later established by computed tomography of the neonatal brain in the knowledge of the characteristic clinical picture.  (+info)

Posterior fossa epithelial cyst: case report and review of the literature. (3/258)

A 49-year old woman with progressive cranial nerve signs and hemiparesis was found at MR imaging and at surgery to have a cyst at the foramen magnum. Immunohistochemistry and electron microscopy showed an epithelial cyst of endodermal origin. MR findings were of an extraaxial mass, with short T1 and T2 times. Unless immunohistochemistry and electron microscopy are used in the final diagnosis of such cysts, all posterior fossa cysts lined by a single layer of epithelium should be described simply as epithelial cysts.  (+info)

Magnetic resonance imaging supplements ultrasonographic imaging of the posterior fossa, pharynx and neck in malformed fetuses. (4/258)

OBJECTIVE: The objective of this study was to compare antepartum ultrasonography and magnetic resonance imaging (MRI) in the diagnosis and exclusion of malformations of the fetal neck, pharynx, skull base and posterior fossa in late pregnancy. MATERIALS AND METHODS: The study involved 26 women and 27 fetuses with ultrasonographically or clinically suspected abnormalities of the fetal neck, pharynx or central nervous system (CNS). Findings obtained by ultrasound were compared with those obtained by MRI (1.5 T) in the last trimester. RESULTS: In cases with CNS malformation (n = 19), MRI provided additional information on the anatomy of the foramen magnum and posterior fossa in nine cases (47%). When antepartum ultrasonography indicated malformation of the soft tissues of the neck or pharynx (n = 8), MRI provided additional information on diagnosis or exclusion of the abnormality in six cases (75%). The imaging capacity of the anatomy of the naso-, oro- and hypopharynx, trachea, esophagus and cervical skin outlines was better with MRI. CONCLUSIONS: MRI proved to be a valuable supplementary method to ultrasound in obtaining accurate information from the fetal neck, pharynx and posterior fossa, particularly when acoustic shadowing by bony structures or adjacent malformation impaired the quality of the ultrasonographic examination.  (+info)

Midline cerebellar cystic schwannoma : a case report. (5/258)

An extremely unusual case of a cystic schwannoma in the region of the inferior vermis and posterior to the fourth ventricle in a fifteen year old boy is reported. The cystic tumour caused partial obstruction to the outflow of cerebrospinal fluid from fourth ventricle and resulted in development of supratentorial hydrocephalus. On investigations, the schwannoma simulated a Dandy-Walker cyst. The boy presented with symptoms of increased intracranial pressure. On surgery, the lesion was not arising from any cranial nerve, nor was it attached to brain parenchyma, blood vessel or to the dura. The possible histogenesis of the cystic schwannoma in a rare location is discussed.  (+info)

Avulsion fracture of the anterior half of the foramen magnum involving the bilateral occipital condyles and the inferior clivus--case report. (6/258)

A 38-year-old male presented with an avulsion fracture of the anterior half of the foramen magnum due to a traffic accident. He had palsy of the bilateral VI, left IX, and left X cranial nerves, weakness of his left upper extremity, and crossed sensory loss. He was treated conservatively and placed in a halo brace for 16 weeks. After immobilization, swallowing, hoarseness, and left upper extremity weakness improved. Hyperextension with a rotatory component probably resulted in strain in the tectorial membrane and alar ligaments, resulting in avulsion fracture at the sites of attachment, the bilateral occipital condyles and the inferior portion of the clivus. Conservative treatment is probably optimum even for this unusual and severe type of occipital condyle fracture.  (+info)

Neurodevelopmental outcome after antenatal diagnosis of posterior fossa abnormalities. (7/258)

Posterior fossa abnormalities are sonographically diagnosable in the fetus. Anomalies of this region include Dandy-Walker malformation, enlarged cisterna magna, and arachnoid cyst. Despite prenatal diagnosis, the uncertainties related to natural history and neurodevelopmental outcome in survivors make patient counseling difficult. The purposes of this study were to determine the accuracy of prenatal diagnosis of these lesions and elucidate long-term neurodevelopmental outcome in survivors in prenatally diagnosed posterior fossa abnormalities. Fifteen cases of posterior fossa abnormalities were reviewed. Antenatal diagnoses of Dandy-Walker malformation was made in 13 of these cases, arachnoid cyst in one case, and enlarged cisterna magna in one case. Hydrocephalus was present in 66% of patients. The sonographic diagnosis was concordant with the pathologic or neonatal radiologic diagnosis in 13 of 15 cases. Seven fetuses (47%) exhibited additional cranial or extracranial anomalies. A karyotypic abnormality (trisomy 18) was found in one of 15 cases of posterior fossa abnormalities. Neurodevelopmental delay was present in 80% of survivors with follow-up study to 4 years of age. Prenatal diagnosis of posterior fossa abnormalities is highly accurate, yet the differential diagnosis can be challenging. Cognitive and psychomotor developmental delays remain commonplace despite early diagnosis and treatment. The approach with families in cases of prenatal diagnosis of posterior fossa abnormalities should include a search for additional central nervous system and extra-central nervous system anomalies in the fetus and counseling of parents regarding potential adverse outcome for survivors.  (+info)

Tumour type and size are high risk factors for the syndrome of "cerebellar" mutism and subsequent dysarthria. (8/258)

OBJECTIVE: "Cerebellar mutis" and subsequent dysarthria (MSD) is a documented complication of posterior fossa surgery in children. In this prospective study the following risk factors for MSD were assessed: type, size and site of the tumour; hydrocephalus at presentation and after surgery, cerebellar incision site, postoperative infection, and cerebellar swelling. METHODS: In a consecutive series of 42 children with a cerebellar tumour, speech and neuroradiological studies (CT and MRI) were systematically analysed preoperatively and postoperatively. Speech was assessed using the Mayo Clinic lists and the severity of dysarthria using the Michigan rating scale. RESULTS: Twelve children (29%) developed MSD postoperatively. The type of tumour, midline localisation, and vermal incision were significant single independent risk factors. In addition, an interdependency of possible risk factors (tumour>5 cm, medulloblastoma) was found. CONCLUSION: MSD often occurs after paediatric cerebellar tumour removal and is most likely after removal of a medulloblastoma with a maximum lesion diameter>5 cm.  (+info)