Teratoid Wilms' tumor, an important variant of nephroblastoma

The teratoid histologic variant of Wilms' tumor is rare, with only 15 prior reported cases. We review these and report an additional case in which a cytogenetic abnormality was identified that has not previously been reported in a teratoid Wilms' tumor.

A medline search revealed 15 previously reported cases of the teratoid variant of Wilms' tumor. We summarized the characteristics of these cases with attention to radiologic appearance, stage, laterality, histology, response to chemotherapy and outcomes.

Characteristic radiologic features suggesting teratoid Wilms' tumor were calcific densities and stippling, or areas of attenuation indicating adipose tissue. The majority of teratoid Wilms' tumor patients had a high tumor stage at presentation (50% stage III or greater). The incidence of bilateral tumors was 38%. Chemotherapy was administered in nine cases and in only one (11%) was there a cytoreductive response. Four deaths (25%) occurred amongst these patients.

Teratoid Wilms' tumors appear to present with a high stage, increased incidence of bilaterality and have a high mortality rate. Treatment strategies should focus on total surgical extirpation, including metastatic sites when feasible, due to this entity's limited response to chemotherapy.