[Inflammatory pseudotumors of the kidney. Report of 2 cases]

Inflammatory pseudotumours of the kidney are rare and raise a problem of differential diagnosis with renal cancer. The authors discuss the diagnostic difficulties of this disease in the light of two patients, aged 32 years and 60 years, admitted for left low back pain (2 cases), large kidney (1 case) and haematuria (1 case). The combination of renal ultrasound and CT suggested a renal tumour or a renal cyst, and MRI suggested a necrotic tumour. Surgical exploration led to tumour excision in one case and surgical biopsy in the other case due to the unresectable appearance of the tumour. Histological examination revealed an inflammatory mass with no signs of malignancy in the two cases. A favourable course was observed in both cases with a normal kidney on subsequent CT. The preoperative diagnosis of pseudotumour remains difficult, despite progress in medical imaging and often requires surgical exploration. The diagnosis is based on a correlation of radiological and histological findings.