Laparoscopic nephron-sparing resection of synchronous Wilms tumors in a case of hyperplastic perilobar nephroblastomatosis

Abstract

Diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) is a rare precursor lesion of Wilms tumor (WT). Because of the increased risk to develop WT in either kidney, current management algorithms of DHPLN merit nephron-sparing strategies, beginning with chemotherapy and close radiographic monitoring into late childhood. After resolution of DHPLN, subsequent detection of a renal nodule mandates resection to exclude WT. Here, we report the case of a 4-year-old girl who developed 2 synchronous nodules in the right kidney more than 2 years after completion of therapy for DHPLN. Because of the early detection and peripheral location of these 2 nodules, laparoscopic nephron-sparing resection of each was performed using ultrasonic dissection. Both nodules were determined on pathology to be favorable histology WT with negative surgical margins. The child was placed on vincristine and actinomycin D therapy for 18 weeks.

Figure 1

(A,B) Magnetic resonance imaging (MRI) of bilateral and diffuse hyperplasticperilobarnephroblastomatosis (DHPLN) in a 10 month-old girl (T2-weighted SPIR sequence:Spectral Presaturation with Inversion Recovery). Note nephroblastic rind (A, arrow) surrounding right kidney and maintaining reniform appearance. The left kidney was predominantly involved in the lower pole (B, arrow).(C-F) MRI 28 months after completing DD-4A therapy for DHPLN.(C,D)T2-weighted pre-contrast MRI shows two heterogeneous peripheral nodules (arrow), which are hyper-intense relative to the surrounding renal cortex.(E,F)T1-weighted post-contrast MRI: (E) Lower pole WT (arrow) arising in right kidney measures 1.6 cm in greatest dimension and shows mild heterogeneous enhancement;(F) Upper pole WT (arrow) measures 1.0 cm in greatest dimension and shows peripheral rim-like enhancement consistent with cystic change.

Figure 2

Laparoscopic nephron-sparing resection of right kidney lower pole (A, B) and upper pole (C, D) WT. (A) Arrow denotes WT protruding from lower pole cortex. Note angiogenesis on surface of WT. (B) Initiating resection plane of lower pole WT with ultrasonic dissector. Arrowhead denotes whitish appearance of cortical scar without angiogenesis typical of WT. U denotes right ureter. (C) Asterisk depicts upper pole WT on posterior aspect of right kidney. (D) Resection plane and margin along upper pole WT (asterisk).

Figure 3

Pathology of lower pole WT. (A) Favorable histology WT (WT) separated from normal renal parenchyma by tumor capsule (c). Note invasion of WT (asterisk) into adjacent and compressed normal kidney. Surgical margin is shown (sm, arrow). (B)Margin of WT with adjacent perilobarnephrogenic rests (PLNR, arrow). Note that the WT is surrounded by a capsule (c) but that the PLNR interfaces directly with the normal adjacent kidney.(C) Lower pole WT breaching its capsule (c) and invading normal kidney. (D) High power view of blastemal-predominant favorable histology WT.