Cystic variant of favorable-histology Wilms' tumor presenting with osteolytic metastasis to the ribs

Cystic neoplasms of the kidney presenting in childhood always present a therapeutic dilemma. Low-risk renal tumors of childhood cover a wide spectrum: cystic nephroma, cystic partially differentiated nephroblastoma and cystic Wilms′ tumor. There are difficulties in differentiating these tumors on preoperative imaging. The present case presented such a therapeutic dilemma and was finally diagnosed as a cystic variant of favorable-histology Wilms′ tumor with osteolytic metastasis to the ribs. The case is presented in view of its rare presentation and the therapeutic and diagnostic challenges involved.

Keywords
Cystic partially differentiated nephroblastoma, cystic renal tumors, Wilms′ tumor