PATH-02. Using DNA methylation profiling to define tumor type and appropriate treatment: a case report and review of the literature of a rare CNS CIC altered sarcoma

The utilization of methylation profiling is increasingly becoming part of the standard evaluation for high-grade malignancies. CNS primary tumors with CIC alteration are a recently recognized CNS tumor entity identified via DNA methylation profiling of primitive neuroectodermal tumors (PNET). PNETs have historically carried a poor overall prognosis; however, CNS tumors with CIC alteration have rarely been described in the literature and much remains to be discovered regarding the presentation, tumor characteristics, outcomes, and ideal treatment strategy to optimize survival in these patients. We describe the case of a 2-year-old Hispanic female with a CNS primary tumor with CIC alteration. This patient initially presented with a five-week history of fatigue, headaches, emesis, and right-sided muscle weakness and was found to have a right-sided supratentorial mixed solid and cystic mass. The initial diagnosis was consistent with a high-grade neuro-epithelial tumor based on histology and standard CNS tumor genetic markers. Due to poorly defined tumor characteristics, a sample was also sent for DNA methylation profiling. The profiling pattern was consistent with a CNS CIC altered sarcoma thereby significantly altering the treatment plan. Accurate diagnosis is critical in managing patients with cancer. DNA methylation profiling has contributed to diagnostic accuracy in these aggressive tumors; however, it also creates challenges with beginning treatment expediently due to the time required for processing and interpretation. This case illustrates the positive utility of DNA methylation to better characterize tumor types and the impact this has on both treatment as well as prognosis.