Intracranial epidermoid cyst in a cat / Cisto epidermoide intracraniano em um gato

ABSTRACT: Epidermoid cysts, also known as epidermal and keratin cysts, or congenital cholesteatomas are benign congenital non-neoplastic tumors, rarely observed in the brain of humans and some animal species (dogs, horses, mice, and rats). Histologically, they are composed of laminated, concentrically arranged keratin surrounded by a thin layer of stratified squamous epithelium. We describe a case of intracranial epidermoid cyst in a 6-year-old mixed-breed male cat in southern Brazil. The patient presented central vestibular syndrome. Given the poor prognosis and the fact that it belonged to a shelter with many dogs and cats, the owner requested euthanasia, and a thorough post-mortem examination was conducted immediately after death. The definitive diagnosis was based on histopathological findings. To the best of our knowledge, this is the first report of an intracranial epidermoid cyst in a cat.

RESUMO: Cisto epidermoide, também denominado cisto epidermal, cisto de queratina ou colesteatoma congênito é um tumor não neoplásico, benigno e congênito raramente encontrado no encéfalo de humanos e de algumas poucas espécies animais (cães, equinos, camundongos e ratos). Histologicamente, esse tumor é composto por queratina laminada concentricamente arranjada e circundada por uma fina parede de epitélio escamoso estratificado. Descreve-se um caso de cisto epidermoide intracraniano em um gato, macho, sem raça definida, de seis anos de idade, no sul do Brasil. O paciente foi encaminhado para atendimento veterinário por apresentar sinais de síndrome vestibular central. Devido ao mau prognóstico e por pertencer a um abrigo com muitos cães e gatos, o proprietário optou pela eutanásia e o paciente foi encaminhado para a realização de necropsia. O diagnóstico definitivo foi baseado nos achados histopatológicos. Pelo conhecimento dos autores, este é o primeiro relato de um cisto epidermoide intracraniano em um gato.

Intracavitary Radiation Therapy for Recurrent Cystic Brain Tumors with Holmium-166-Chico : A Pilot Study

OBJECTIVE: Intracavitary injection of beta-emitting radiation source for control of cystic tumors has been tried with a benefit of localized internal radiation. The authors treated cystic brain tumor patients with Holmium-166-chitosan complex (Ho-166-chico), composed of a beta-emitting radionuclide Holmium-166 and biodegradable chit polymer, and evaluated the safety and effective measurement for response. METHODS: Twenty-two patients with recurrent cystic brain tumor and/or located in a deep or eloquent area were enrolled in this pilot study. The cyst volume and wall thickness were determined on CT or MRI to assess radiological response. The activity of Ho-166-chico injected via Ommaya reservoir was prescribed to be 10-25 Gy to the cyst wall in a depth of 4 mm. RESULTS: There was neither complications related to systemic absorption nor leakage of Ho-166-chico in all 22 patients. But, two cases of oculomotor paresis were observed in patients with recurrent craniopharyngioma. Radiological response was seen in 14 of 20 available follow-up images (70%). Seven patients of 'evident' radiological response experienced more than 25% decrease of both cyst volume and wall thickness. Another 7 patients with 'suggestive' response showed decrease of cyst volume without definitive change of the wall thickness or vice versa. All patients with benign tumors or low grade gliomas experienced symptomatic improvement. CONCLUSION: Ho-166-chico intracavitary radiation therapy for cystic tumor is a safe method of palliation without serious complications. The determination of both minimal effective dosage and time interval of repeated injection through phase 1 trial could improve the results in the future.

Clinical Significance of Neonatal Parafrontal Horn Cysts Detected by Cranial Sonography

PURPOSE: To describe the significance, incidence and characteristics of sonographic findings and long term outcomes of parafrontal horn cysts detected by screening cranial sonography done within the first week following birth. MATERIALS AND METHODS: 2122 first cranial ultrasound scans performed over a five year period were retrospectively evaluated and 23 neonates with parafrontal horn cysts were found (which are different from secondary cystic lesions). 17 cases had a birth weight of 2400 gm with gestation between 34 and 41 weeks. The size, shape and location of the parafrontal horn cysts and other associated abnormalities shown on the cranial sonogram were evaluated and sequential ultrasound study, maternal records, neonatal events and neurodevelopmental evaluations were retrospectively assessed. RESULTS: Of the 23 subjects, 21 had isolated parafrontal horn cysts and 2 had subependymal hemorrhages. There was no record of any abnormal perinatal history. The cysts were bilateral in 20 neonates and unilateral in the others. The size of the cysts ranged from 3 to 18 mm in diameter (mean 9 mm). Sonographic features of the parafrontal horn cysts were distinctive morphology (elliptical, thin walled) and location (adjacent to the tip of the frontal horn). In 17 of the cases a follow-up cranial sonography was performed, and all parafrontal horn cysts disappeared within 3 to 6 months. Neurodevelopmental outcomes were normal in those 17 cases. CONCLUSION: Screening cranial sonography of neonates discovers isolated parafrontal horn cyst. The incidence of parafrontal horn cysts in neonates in our study was 1.1%. They are present in the first week following birth and resolve themselves without medical treatment within a few months. In addition, they show normal neurodevelopment. The parafrontal cysts are suspected to be a benign variant of normal neurodevelopment.

Stereotactic Surgery of Neurocysticercosis

The authors had performed stereotactic surgery to diagnose and treat 2 cases of neurocysticercosis under the local anethesia. Generally, such the open surgery need a general anethesia which may increase the chance of brain parenchyml injury. However, the stereotactic surgery has the advantage of being an easy and precise procedure under local anethesia. The authors reviewed the literature and discussed the stereotactic surgery in the diagnosis, and treatment of neurocysticercosis.