Grade II atypical choroid plexus papilloma with normal karyotype

Posterior fossa choroidplexus papilloma in the pediatric population: case series and literature review

Choroid plexus papillomas (CPPs) are rare benign neoplasms which are particularly uncommon in the posterior fossa in children. We herein present a case series of five patients treated at a tertiary care hospital. A comprehensive literature review was also carried out. The patients treated at the tertiary care hospital were aged between 4 and 16 years. Gross total resection (GTR) was initially achieved in two patients. All patients showed clinical improvement. Moreover, 27 articles published between 1975 and 2021 were selected for the literature review, totaling 46 patients; with the 5 patients previously described, the total sample was composed of 51 cases, With a mean age was 8.2 years. The lesions were located either in the fourth ventricle (65.3%) or the cerebellopontine angle (34.7%). Hydrocephalus was present preoperatively in 66.7% of the patients, and a permanent shunt was required in 31.6% of the cases. The GTR procedure was feasible in 64.5%, and 93.8% showed clinical improvement. For CPPs, GTR is the gold standard treatment and should be attempted whenever feasible, especially because the role of the adjuvant treatment remains controversial. Neuromonitoring is a valuable tool to achieve maximal safe resection. Hydrocephalus is common and must be recognized and promptly treated. Most patients will need a permanent shunt. Though there is still controversy on its efficacy, endoscopic third ventriculostomy is a safe procedure, and was the authors' first choice to treat hydrocephalus.

Choroid plexus carcinomas are characterized by complex chromosomal alterations related to patient age and prognosis

Choroid plexus carcinoma is a malignant brain tumor predominantly occurring in young children. Only limited data are available regarding the underlying molecular genetic alterations. Therefore, molecular inversion probe single nucleotide polymorphism (MIP SNP) arrays were performed on a series of 26 neuropathologically well-characterized choroid plexus carcinomas. Recurrent copy number losses of chromosomes 5, 6, 16, 18, 19, and 22 as well as gains of chromosomes 1, 2, 4, 12, and 20 were identified. Furthermore, GISTIC analysis identified significant recurrent gains of 17 genes in 9 regions, and recurrent losses of 96 genes in 14 regions. Clustering analysis separated choroid plexus carcinomas into two groups: one characterized by marked losses and the other characterized by gains across the chromosomes. Chromosomal losses of 9, 19p, and 22q were significantly more frequent in younger children (<36 months), whereas gains on chromosomes 7 and 19, and chromosome arms 8q, 14q, and 21q prevailed in older patients. Multivariate analysis revealed that loss of 12q was associated with shorter survival [12 ± 5 months vs. 86 ± 8 months; (mean ± SD; P = 0.001)] and, in addition, 45 smaller chromosomal regions showing genetic alterations significantly associated with survival could be identified. The MIP SNP array profiles also contributed to the diagnosis of two difficult SMARCB1-negative tumors as choroid plexus carcinoma and cribriform neuroepithelial tumor (CRINET), respectively. In conclusion, choroid plexus carcinomas are characterized by complex genetic alterations, which are related to patient age and may have prognostic and diagnostic value.