The Clinical Presentation of Rhabdoid Tumors of the Kidney † 747

Abstract

The rhabdoid tumor of the kidney (RTK) is a rare but highly malignant pediatric tumor. RTK was first considered a subtype of Wilms tumor but is now considered a unique tumor. The clinical presentation of RTK has not been established or differentiated from the clinical presentation of Wilms tumors. In particular, the incidence of hematuria has not been distinguished between the two tumors. We reviewed patient flow charts from the National Wilms Tumor Study Group and sent questionnaires to the participating hospitals to obtain additional information regarding presenting symptoms and diagnostic laboratory data in fifty subjects. The subjects ages ranged from 2 days to 3.5 years with a mean age of 11 months. We documented the presence of gross and microscopic hematuria, fever, proteinuria and hypercalcemia. Patients with RTK present at a more advanced stage than do patients with Wilms tumors (p<0.005). While 75% of patients with RTK presented with stage III(46%), IV(27%) or V(4%), 67% of patients with Wilms tumors presented with stage I(41%) or II(26%). Hematuria was present in 84.4%(27/32) of the subjects with RTK. Gross hematuria was a presenting symptom in 59%(22/37) of patients with RTK compared to 18% of patients previously reported inWilms (p<0.005). Microscopic hematuria was seen in 76%(22/29) of patients with RTK compared to 24% of patients previously reported inWilms (p<0.005). A fever was found in 44%(16/36) of patients with RTK compared to 22% of patients previously reported inWilms (p<0.005). Proteinuria was seen in 27%(10/37). Hypercalcemia was seen 26%(6/23). Hypercalcemia has been associated with RTK, but the incidence of 26% has not previously been defined. Although diagnosis of any renal mass still must be confirmed with histopathological features, a distinct clinical presentation with fever, hematuria, a young age and high tumor stage at presentation may suggest the diagnosis of RTK.