Kidney, Wilms tumour

Wilms tumor (Nephroblastoma) is the most common pediatric renal tumor. Most commonly, it is sporadic but can be associated with several syndromes like WAGR, Denys-Drash and Beckwith-Wiedemann syndrome.

This case is an example of a triphasic Wilms tumour, and is composed of undifferentiated blastema (diffuse, cordlike or basaloid patterns of densely packed primitive small blue cells with scanty cytoplasm), fibroblast-like stroma, and epithelial elements (abortive tubules or glomeruli with elongate nuclei having molded shapes). It may also have heterologous differentiation within the stromal component. Large size, advanced stage, age > 2 years and anaplasia are considered poor prognostic factors.