Coexisting differentiated neuroblastoma and ossifying renal tumor of infancy in a patient

We presented a 5-month-old boy with differentiated neuroblastoma and ossifying renal tumor of infancy (ORTI) arising at the left adrenal gland and upper pole of the ipsilateral kidney, respectively. They were located in the adjacent organs with different morphology and immunohistochemistry characteristics. To our best knowledge, coexistence of differentiated neuroblastoma and ORTI in a patient has never been reported. In our report, two contiguous lesions might be represented collision tumor, originated from the same clusters of immature cells and triggered by different mechanism.