Prognostic Implication of DNA Methylation Signature in Atypical Choroid Plexus Papilloma With Intracranial Dissemination

An underestimation of pathologic diagnosis could be expected if disseminated choroid plexus tumors (CPTs) are diagnosed as lower grade tumors. Thus, molecular diagnosis using genome-wide DNA methylation profiling may be useful for clarifying the malignant potential of the tumor entity. Herein, we report a 2.7-year-old girl of pathologically atypical choroid plexus papilloma with intracranial dissemination. She was treated without radiotherapy and has been well, without recurrence for 32 months following the diagnosis. Subsequently, after a year from the diagnosis, T-stochastic neighbor embedding analysis was performed on methylation data of the case and compared with those of reference data of CPTs, revealing that the case was separated from the cluster of "Plexus tumor subclass pediatric B," which includes a majority of choroid plexus carcinomas with the worst prognosis of these entities, and was categorized into the cluster of "Plexus tumor subclass pediatric A" consisting of choroid plexus papilloma and atypical choroid plexus papillomas diagnosed pathologically. Our case indicates the clinical significance of molecular confirmation for diagnosis among CPTs, particularly lower grade tumors with dissemination.