Leptomeningeal dissemination of pilocytic astrocytoma at diagnosis in childhood: two cases report

Abstract

-Pilocytic astrocytoma (PA) is a benign tumor that rarely spread along the neuraxis. At the moment there are no more than five cases of leptomeningeal dissemination (LD) from PA at diagnosis described in the literature. Different patterns of presentation or recurrence may be noted: local recurrence, malignant transformation, multicentric disease or metastatic disease. LD and multicentric disease can be distinct pathological entities. We report two cases and analyse literature, emphasizing leptomeningeal spread at presentation. Hydrocephalus, biopsy and parcial ressection are likely to be favorable factors to the occurrence of LD. Otherwise, LD may be part of natural history of PA, as evidenced by its ocurrence in non-treated cases.KEY WORDS: pilocytic astrocytoma, leptomeningeal dissemination, multicentric disease, cerebrospinal fluid, metastasis, radiation therapy, chemotherapy, hydrocephalus.Disseminação leptomeníngea de astrocitoma pilocítico ao diagnóstico: relato de dois casos. Disseminação leptomeníngea de astrocitoma pilocítico ao diagnóstico: relato de dois casos. Disseminação leptomeníngea de astrocitoma pilocítico ao diagnóstico: relato de dois casos. Disseminação leptomeníngea de astrocitoma pilocítico ao diagnóstico: relato de dois casos. Disseminação leptomeníngea de astrocitoma pilocítico ao diagnóstico: relato de dois casos.RESUMO -Astrocitoma pilocítico (AP) é tumor benigno que raramente se dissemina ao longo do neuroeixo. Até o momento não há mais que cinco casos de AP que se tenham apresentado com disseminação leptomeníngea (DL) descritos na literatura. Diferentes padrões de apresentação ou recorrência podem ser observados: recorrência local, transformação maligna, doença multicêntrica ou doença metastática. DL e doença multicêntrica podem ser entidades diferentes. Relatamos dois casos e analisamos a literatura. Hidrocefalia, biópsia e ressecção parcial são provavelmente fatores predisponentes à DL. Por outro lado, DL pode ser parte da história natural de AP, como pode ser evidenciado pela sua ocorrência em casos não tratados.

Unusual dissemination patterns of low-grade astrocytomas in childhood

“…Figueiredo et al have recently described two cases 9 . Zorlu et al described the case of a 4-year old girl with signs of leptomeningeal dissemination consequent to subtotal resection of a pilocytic cerebellar astrocytoma 10 .…”

Heterogeneity of histopathological presentation of pilocytic astrocytoma – diagnostic pitfalls. A review

“…Dissemination of cerebellar PAs can be associated with obstructive hydrocephalus leading to an unfavourable prognosis [32,41,42]. Leptomeningeal dissemination of the cerebellar tumours into the spinal cord might occur many years after primary surgery [45,66,78]; less commonly the meningeal seeding appears at the initial presentation [67].…”

Leptomeningeal dissemination of pilocytic astrocytoma in a 17-year-old boy

“…Leptomeningeal dissemination of brain tumors is a rare phenomenon and occurs more commonly in ependymomas, germ cell tumors, medulloblastoma, and high-grade gliomas (6). leptomeningeal dissemination of low-grade astrocytoma, particularly those diagnosed at presentation, has rarely been reported in the medical literature with fewer than 60 cases (3,6).…”

“…Although PA is associated with an excellent outcome and long-term survival, dissemination of PA to leptomeninges, a rare phenomenon with limited cases published in the medical literature, has been linked with an unfavorable prognosis (6,10). Extension of PA to the third ventricles is uncommon but associated with obstructive hydrocephalus requiring an invasive procedure to divert the cerebrospinal fluid (CSF) flow (8).…”