A PREVIOUSLY HEALTHY 22-month-old black male child was noted to have an abdominal mass. On examination there was a 10×8-cm, firm, right upper-quadrant mass. Results of laboratory studies were within normal limits. Computed tomography with contrast of the abdomen and magnetic resonance imaging (Figure 1) were performed. Surgical excision and results of pathologic examination of the mass are shown in Figure 2 to Figure 4.
Diagnosis and Discussion
Wilms' Tumor (Nephroblastoma)
Abdominal masses can be caused by congenital lesions, neoplasms, or inflammatory processes such as abscess formation from appendicitis or Crohn's disease or by an infected cyst from a ventriculoperitoneal shunt. Neoplasms account for approximately half of abdominal masses, but hydronephrosis is the most common cause in newborns. Less common causes include multicystic kidney, duplications, mesenteric cysts, and hydrocolpos.
Wilms' tumor (nephroblastoma) is the most common intra-abdominal malignant neoplasm in childhood. Frequently, the parent discovers the flank mass. Most cases