Cisto aracnóideo intradiploico não traumático – Relato de caso

Resumo

Existem apenas 14 casos descritos de cistos aracnóideos intradiploicos sem traumatismo craniano prévio. O objetivo deste estudo é relatar um caso de cistos aracnóideos intradiploicos e alertar para a possibilidade deste diagnóstico entre as lesões osteolíticas do crânio. Um paciente masculino de 74 anos, com histórico de adenocarcinoma de próstata, tratado com radioterapia há 2 anos, realizou tomografia de crânio para investigação de tontura. Esta mostrou lesão lítica de 2 cm parietoccipital direita. Não havia história de trauma ou alteração neurológica. A ressonância magnética mostrou tecido isointenso ao parênquima cerebral preenchendo a cavidade óssea. O paciente foi submetido à craniectomia ao redor da lesão e foi identificada herniação de tecido encefálico para dentro da díploe craniana. Ao exame anatomopatológico não foram encontradas células neoplásicas, mas sim a presença de cavidade intraóssea com superfície interna recoberta por faixa de tecido conjuntivo fibrilar frouxo e tecido cerebral com morfologia preservada, estabelecendo o diagnóstico de cisto intradiploico com herniação de tecido cerebral. Cistos aracnóideos intradiploicos são geralmente achados incidentais. A cirurgia é necessária para o diagnóstico, mas pode ser evitada em pacientes assintomáticos e quando não há evidência de neoplasia maligna. Portanto, se o tratamento conservador for escolhido, sugere-se seguimento clínico e imagenológico, já que a história natural é desconhecida.

Abstract

There are only 14 reported cases of intradiploic arachnoid cysts without prior head injury. The aim of this study is to report a case of intradiploic arachnoid cysts. Neurosurgeons must be aware of this possibility among osteolytic lesions of the skull. A male patient, 74 years old, with a history of prostate adenocarcinoma treated with radiotherapy for two years, held cranial tomography for investigation of dizziness. This showed a 2 cm parietal-occipital osteolytic lesion. There was no history of trauma or neurological disorder. The magnetic resonance imaging showed tissue filling the bone cavity that was isointense to brain parenchyma. The patient underwent craniectomy around the lesion, and brain tissue herniation was identified into the cranial diploe. Histopathology did not demonstrate neoplastic cells; the inner surface of the bone cavity was covered by loose fibrillar connective tissue and brain tissue with preserved morphology, establishing the diagnosis of IAC with brain tissue herniation. Intradiploic arachnoid cysts are usually incidental findings. Surgery is required for diagnosis, but it can be avoided in asymptomatic patients when there is no evidence of malignancy. Therefore, if conservative treatment is chosen, close clinical and imaging follow-up is advised, since IAC natural history is unknown.

Palavras-chave

cistos aracnóideos - aracnóideos/patologia - aracnóideos/fisiopatologia - aracnóideos/cirurgia - craniotomia

Keywords

arachnoid cysts - arachnoid/pathology - arachnoid/physiopathology - craniotomy

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