NCOG-62. CNS SARCOMA IN A TODDLER WITH NOVEL BALANCED TRANSLOCATION OF t(8;11)(q13;q13)

A CASE REPORT A 23-month-old boy was noted to have a brain tumor after being evaluated for chronic global developmental delay. The initial neurological exam was concerning for left leg circumduction and drag. Further investigation with MRI demonstrated a 7 x 9.3 x 7.4 cm supratentorial cystic encapsulated mass identified in the right lateral ventricle with heterogeneously enhancing mural nodule measuring 0.9 x 2.7 x 3.3 cm in diameter. Capsular enhancement was also noted after contrast administration. No diffusion restriction was seen. Mass effect on septum pellucidum was seen along with an increase in size of the left lateral ventricle. Following which the patient underwent right posterior parietal craniotomy and gross total resection of the tumor. Pathology report based on the cellular appearance, cell density, presence of necrosis, and the proliferative activity classified the tumor as likely intermediate grade undifferentiated sarcoma, mostly mesenchymal in origin. Tumor cytogenetics showed balanced translocation (8;11) (q13; q13) in all metaphase cells. Cytogenetics performed on the blood sample showed normal karyotype, suggesting that the translocation seen in tumor cells was somatic in nature rather and not a germline mutation. As the radiological signs and the long clinical course of the disease (evidenced by global developmental delay noted more than a year prior to a presentation and no signs of disseminated disease) suggested it to be a low-grade tumor a decision was made not to treat aggressively with further chemo and radiotherapy. However, the pathology of the tumor was suggestive of a primary malignant undifferentiated sarcoma of the brain. The patient continued to do well with no signs of recurrence on MRI and/or clinical picture for 4 years after the initial surgery. DISCUSSION Primary CNS sarcoma is rare. Balanced translocation (8;11) (q13; q13) has not been described in the literature before.