Congenital Lung Lesions (CPAM)

Favorable histology Wilms tumor comprises three histologic components: blastemal, stromal, and epithelial; tumors containing only two of these components retain favorable classification. Wilms tumors characteristically displace adjacent structures outward rather than infiltrating around them, a growth pattern that distinguishes them from neuroblastoma.

Wilms tumor treatment involves surgery and chemotherapy, with the specific approach depending on tumor extent. For unilateral tumors, the strategy is nephrectomy (removal of the whole kidney). For bilateral Wilms tumors—which occur in 8 to 10% of children—the approach differs to avoid forcing dialysis; the strategy avoids removing both kidneys. Patients with lung lesions (metastatic disease) receive 3-drug chemotherapy. Treatment protocols vary between COG (North American) and SIOP (Western European) approaches, which have taken different directions in their management strategies.

Management of Wilms tumor depends on laterality. For unilateral tumors, the strategy is complete nephrectomy. For bilateral Wilms tumors (8–10% of cases), the approach differs: rather than removing both kidneys and forcing dialysis, treatment involves chemotherapy and nephron-sparing strategies. Bilateral tumors require careful attention because discordant pathology occurs in up to 20% of cases between kidneys. Favorable histology tumors contain blastemal, stromal, and epithelial components; tumors with only two components remain favorable. Treatment protocols have evolved from varied historical approaches to more standardized regimens.

Favorable histology Wilms tumor comprises three components: blastemal, stromal, and epithelial. Tumors containing all three components are classic triphasic tumors; however, tumors with only two of these components are still classified as favorable histology. The stromal and epithelial elements, including glomerular structures and the amount of stroma, characterize the favorable histology pattern.