Lumbosacral ectopic nephrogenic rest unassociated with spinal dysraphism.

Nephrogenic rests (NRs) are thought to originate from persistent nephrogenic blastema and are considered precursor lesions of Wilms' tumor (WT). These rests usually occur as perilobar and intralobar lesions in the kidney and, rarely, in ectopic sites. We report a midline lumbosacral ectopic NR in a healthy full-term newborn male with no family history of WT or WT-associated syndromes.

Renal inflammatory pseudotumor.

A previously healthy 37-year-old man had evaluation of abdominal pain, which had persisted after abrupt onset with fever and hematuria. Although the fever and hematuria had spontaneously resolved after 1 week, the abdominal pain had worsened over a 4-month period. Predicated upon computed tomography and with a presumed diagnosis of renal cell adenocarcinoma, left radical nephrectomy was done.