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Título

Atypical choroid plexus papilloma of unusual topography: case report

Resumo

We describe the case of an 11-year-old child with headache associated with dizziness lasting approximately 1 year. An imaging exam was performed that showed an expansive lesion affecting the cerebellar peduncle laterally to the fourth ventricle on the right. After surgery, the pathological anatomy confirmed an atypical choroid plexus papilloma in an unusual topography.
Choroid plexus tumors (CPT) are rare neoplasms of the central nervous system originating from the choroid plexus epithelium and therefore typically located in the ventricles. Atypical choroid plexus papilloma corresponds to a rare entity of these tumors, having been incorporated into the WHO classification of central nervous system tumors only in 2007. It is categorized as grade II, being between choroid plexus papillomas (grade I) and choroid plexus carcinomas (grade III). It has increased cell density, high mitotic activity and nuclear polymorphism, behaving more aggressively than the choroid plexus papilloma. In this sense, they present a higher risk of metastasis and recurrence, unlike papillomas, in which there is a high rate of cure after complete resection. In the molecular analysis of atypical choroid plexus papilloma, recurrent gain of the short arm of chromosome 8 and long arm of chromosome 9 can be observed. Its main location is the lateral ventricles and, unlike adults, it is rarely located in the posterior fossa. Total tumor resection is the recommended treatment and is related to the best prognosis for the patient. The CPT-SIOP-2000 study concluded that in partially resected cases, in turn, there is benefit in the indication of chemotherapy and radiotherapy.
Due to the rarity in the literature, we present the case to remember this differential diagnosis in posterior fossa tumors.