Melanocitoma meníngeo del ángulo pontocerebeloso: claves imagenológicas para su abordaje / Cerebellopontine meningeal melanocytoma: keys for imaging diagnostic approach

Resumen: Las lesiones del ángulo pontocerebeloso (APC) representan el 6 al 10% de las neoplasias intracraneales, siendo los schwannomas vestibulares y meningiomas los más comunes. Sin embargo, hasta el 15% pueden ser otras lesiones, entre ellas las derivadas a partir de restos de células melanocíticas presentes en las leptomeninges. El diagnóstico diferencial de las patologías tumorales del APC es extenso, siempre teniendo en cuenta las lesiones más comunes. Sin embargo, cuando las características radiológicas no son las esperadas, el enfoque debe orientarse hacia las lesiones inusuales, poniendo en contexto las diferentes estirpes celulares que pueden dar origen a las neoplasias en esta localización, como las neoplasias melanocíticas. Se presenta el caso de un masculino de 74 años con síndrome cerebeloso de tórpida evolución, al cual se le realiza RM de cerebro contrastada, identificando una lesión de base dural en el APC izquierdo, con hiperintensidad de señal en T1 e hipointensidad en T2, atípico para las lesiones más comunes en esta región, que sugiere su contenido melanocítico.

Abstract: Cerebellopontine angle tumors (CPA) represent approximately 6 to 10% of intracranial tumors. Vestibular Schwannomas and meningiomas are the most common, however up to 15% can be of other origin, including from melanocytes derived from the neural crest. The differential diagnosis of CPA pathologies is extensive, always taking into account the most common ones. However, if the radiological characteristics are not the expected, the approach should be directed towards unusual lesions, putting into context the different cell lines that can give rise to the neoplasm at this location, such as melanotic neoplasms. We present a case of a 74-year-old male, who presented with a cerebellar syndrome. Due to an atypical clinical evolution, a contrast enhanced head MRI was performed, revealing a dural based tumor on the left CPA, which was hyperintense on T1 and hypointense on T2 weighted sequences, which is not expected from the common lesions at this region and suggested it's melanotic content.

[Cysticercosis of the cerebellopontine angle: treatment with single-dose praziquantel]. / Cisticercosis del ángulo pontocerebeloso: tratamiento con dosis única de praziquantel.

INTRODUCTION: Praziquantel has not been considered useful for therapy of subarachnoid cysticercosis. However, recent studies suggest that the introduction of a new regimen of praziquantel therapy, that includes the administration of higher doses of the drug at shorter intervals, may improve pharmacokinetic properties of praziquantel and increase its efficacy in this form of the disease. CLINICAL CASE: A 28 year-old woman presented with a six month history of headache, vomiting, nystagmus, right peripheral facial palsy, and left hemiparesis. Computerized tomography (CT) scan of the head revealed a large cysticercus in the right cerebellopontine angle cistern compressing the brain-stem. She was treated with praziquantel 100 mg/kg in three divided doses at two hours apart. Thereafter, she received three 8 mg doses of intravenous dexamethasone given 6, 24 and 48 hours after the last dose of praziquantel. She improved after therapy, with total resolution of hemiparesis. Control CT showed progressive reduction and size and further disappearance of the cystic lesions three months later. CONCLUSION: This single-dose regimen of praziquantel seems to be effective for therapy of subarachnoid cysticercosis. Further studies with a large number of patients are needed to confirm the efficacy of the drug in this form of the disease.

Hemifacial spasm and arterial hypertension.

BACKGROUND: Hemifacial spasm (HFS) is a form of segmental myoclonus often associated with vascular compression of the seventh nerve at its exit in the brain stem. Although a few uncontrolled studies describe the association of arterial hypertension (AH) with HFS, their relationship remains to be elucidated. OBJECTIVES: To compare the clinical and radiologic features of patients with HFS and subjects with blepharospasm (BLS) with special emphasis on the presence of AH. MATERIAL AND METHODS: Chart review of all patients with HFS and BLS seen at a hospital-based movement disorders clinic from July 1993 through March 1998, analyzing the following parameters: gender, age at onset, frequency of AH, and abnormalities on computerized tomography (CT) or magnetic resonance imaging (MRI) studies. Neuroimaging studies (52 CT and 14 MRI) were performed in 45 subjects with HFS and in 21 with BFS. All patients were examined by one of the authors (FC). RESULTS: HFS and BLS were diagnosed in 48 (31 women, 17 men) and 34 (28 women, 6 men) patients, respectively. The age at onset was 50.1 +/- 12.6 years in HFS and 50.3 +/- 16.5 years in BLS. AH was diagnosed in 32 (66.7%) subjects with HFS and in 13 (38.2%) patients with BLS (chi-square p = 0.01). Neuroimaging evidence of vascular tortuosity in the cerebello-pontine angle was identified in 16 (25.4%) patients, all of whom had HFS (38.1%). Thirteen of 37 patients with AH who had imaging studies displayed vascular tortuosity in the cerebello-pontine angle (chi-square p = 0.01). CONCLUSIONS: AH is significantly more common in HFS than in BLS. AH is related to vascular tortuosity in the cerebello-pontine angle. Our findings suggest that AH may be an important risk factor for HFS.