Inflammatory Pseudotumor of the Renal Pelvis.

Inflammatory pseudotumor of the kidney is a rare disease of unknown etiology. There are no specific clinical or radiologic findings. The lesion can mimic renal cell carcinoma or transitional cell carcinoma depending on the site of involvement. These tumors, if diagnosed correctly, may respond to medical management. We present a case in which an inflammatory pseudotumor of the renal pelvis was misdiagnosed as a transitional cell carcinoma and unwarranted surgical intervention was performed. A 39-year-old man presented with left flank pain and gross hematuria. On MRI, there was a hypointense 2.4 × 1.8 cm lesion involving the left renal pelvis. The urine cytology and biopsy of the lesion were inconclusive. On follow-up cans the lesion increased in size and patient had repeated hematuria. The lesion was clinically presumed to be a transitional cell carcinoma of the left renal pelvis. A laparoscopic left side nephroureterectomy along with bladder cuff excision and para-aortic lymphadenectomy was performed. The histology report revealed the lesion to be inflammatory pseudotumor of the renal pelvis. Inflammatory pseudotumor should always be considered in differential diagnosis of pelvic tumors, especially when image findings and biopsies are inconclusive.