F-18 FDG PET/CT imaging of metastatic extrarenal Wilms tumor arising in the inguinal canal.

Extrarenal Wilms tumor (ERWT) is rare, and has been reported sporadically in the literatures. ERWT can arise anywhere from the renal bed to the testes; reported locations of ERWTs include the retroperitoneum, inguinal canal, endocervix, uterus, epididymis, and sigmoid mesocolon. We report the F-18 FDG PET/CT imaging findings of an ERWT arising from the inguinal canal in a 9-year-old boy. F-18 FDG accumulated in the metastatic lesions of the lung and mediastinal lymph nodes, as well as the primary ERWT. After chemotherapy, a follow-up PET/CT showed complete metabolic remission. F-18 FDG PET/CT is useful in detecting primary and metastatic ERWTs and in evaluating treatment response.