Botryoid Wilms? tumor: a report of two cases

Abstract

We report two rare cases of botryoid Wilms' tumor (BWT) occupying the renal collecting system with no macroscopic parenchymal mass. In case 1, a 3-year-old boy presented with a mass in the right flank, low-grade fever, abdominal pain, and macrohematuria. Radiology revealed an enlarged right kidney with a heterogeneous mass occupying a large part of the dilated renal calyx, pelvis, and ureter. Radical right nephroureterectomy was performed. The histopathologic diagnosis was nephroblastoma, and the pedicle of the tumor was attached to the renal parenchyma near the pelvic wall. In case 2, a 2-year-old boy presented with macrohematuria, and the clinical course was almost the same as in case 1. No local recurrence or metastatic spread has been detected for 4 years postoperatively in case 1 and for 9 months postoperatively in case 2.

Botryoid Wilms’ tumor: report of two cases

“…[1,2] In our two cases, the renal parenchyma was shown around the masses by CT. The border between the lesion and the renal parenchyma was not clear on the unenhanced scan, but it was obvious on the enhanced scan.…”

“…The mass shows no or slight enhancement on the contrasted scan. [1][2][3][4] The density of the lesion was similar to that of the renal parenchyma (CT value approximately 16-29 HU). Enhanced CT revealed that the lesion presented with mild or moderate enhancement (41-67 HU).…”

“…[5] Previous studies found that botryoid Wilms' tumor occurred in unilateral kidney. [1][2][3][4][5][6][7][8] In our study, the masses occurred in the renal pelvis and calyx bilaterally in case 1. Inoue et al [1] reported that multiple calcifi cations can be seen in the tumor as in our case 1.…”

“…Its appearance is similar to that of botryoid sarcoma, so called botryoid Wilms' tumor. [2][3][4][5] Herein we report two cases of this tumor.…”

“…It usually occurs as a mass in the renal parenchyma and expands into the surrounding tissues. [1][2][3] It rarely arises from the renal pelvicaliceal wall, occupying the collecting system with minimal parenchymal involvement. Its appearance is similar to that of botryoid sarcoma, so called botryoid Wilms' tumor.…”