Opsoclonus-Myoclonus-Associated Neuroblastoma with Bone Marrow Metastases: What Would Be the Best Treatment Option?

A 1.9-year-old girl was presented to the hospital with dancing eye movements, ataxia, and behavioral disorders. The MRI showed a retroperitoneal tumor (transversal size: 3.9 x 2.5 cm, craniocaudal size: 4.6 cm) extending from T12 to L3 vertebral bodies (Figure), which was suspicious for neuroblastoma. Afterwards, biopsy of the lesion and bone marrow was performed. The initial pathological evaluation (CD56+, PHOX2B+, NKX2-, Ki67 50%-55%, NSE+, CD99-) of the tumor and bone marrow confirmed the diagnosis of poorly differentiated, high-risk neuroblastoma.