Clinicopathological analysis of renal inflammatory pseudotumors presenting as the unilateral solitary masses.

Renal inflammatory lesions rarely present as unilateral solitary mass. These types of lesions are often misdiagnosed as renal tumors that lead to unnecessary nephrectomy. So far there are very few comprehensive studies about both their clinical features and pathologic characteristics of these inflammatory pseudotumors. Six renal inflammatory pseudotumors were identified in atotal of 1195 radical or partial nephrectomy cases retrospectively reviewed in our institution. The inflammatory lesions included xanthogranulomatous pyelonephritis (2 cases), renal tuberculosis (1 case), renal malakoplakia (1 case), IgG4-related tubulointerstitial nephritis (1 case), and renal Wegener's granulomatosis (1 case). All patients underwent radical nephrectomy because they had the unilateral renal solitary mass by the imaging examination. Following the postoperative pathological diagnosis, these patients received anti-inflammatory therapy according to their specific etiology. In conclusion, the attention must be paid for rare renal inflammatory pseudotumors that may mimic tumors since these diseases require a total different treatment strategy from neoplastic diseases.