BRAINSTEM MEDULLOBLASTOMA IN A CHILD: A CASE REPORT

Resumo

Introduction: Medulloblastoma is primarily a histologically heterogeneous malignant neoplastic disorder of the first 20 years of life. It usually arises within the cerebellum, and the vermis is the most common site. The expected natural course of untreated lesion is one of rapid progression with seeding into the subarachnoid space. Contemporary therapies combine maximum surgical removal, irradiation and chemotherapy. We present a case of a 7-year-old boy with diffuse brain stem lesion, mainly within the pons and extending to the left middle cerebellar peduncle. Case report: T.E.P., a 7-year-old boy, was admitted to the Hospital Universitário do Oeste do Paraná harboring a three weeks history of diplopia and unsteadiness. A diagnosis of rheumatic fever was made a year ago. The general physical examination was unremarkable, although overweighted. The neurological examination revealed gait ataxia, mainly performing the heel-to-toe walking, Romberg sign, binocular diplopia, gaze horizontal and vertical nystagmus, left hand intention tremor, left upper limb ataxia and dysdiadochokinesis. A head computerized tomography scan demonstrated a space occupying lesion at the level of the brain stem and left middle cerebellar peduncle, displacing the fourth ventricle, without hydrocephalus. The magnetic resonance imaging disclosed the true extension of the lesion, centered at the level of the pons and left middle cerebellar peduncle, where there was a contrast enhancement, but also throughout the brainstem. The patient underwent a left retrosigmoid approach in order to perform a biopsy at the level of the left middle cerebellar peduncle. The anatomopathological studies confirmed a diagnosis of medulloblastoma. Discussion: Medulloblastomas outside the vermis are not common. The present case stresses the necessity of proper histological and immunohistochemical studies aiming the right diagnosis, which has a direct impact on treatment protocols. Yet, even modern imaging techniques alone do not provide definitive diagnosis.