Xanthogranulomatous pyelonephritis (XGPN) is an unusual suppurative granulomatous reaction to chronic infection. It often occurs in the presence of chronic obstruction from a calculus, stricture or tumor. XGPN clinically presents with abdominal mass, pain, weight loss, anemia and pyuria. Here, we report a case of a 50-year-old woman who had extensive XGPN complicated by a rarely seen unusual devascularization of the transverse and descending colon resulting in ischemic colitis owing to compression by a large mass. The abdominal mass was the largest to be reported to date worldwide. The etiologies, symptoms and signs, complications, diagnosis and treatment are also reviewed in this article.