A strange renal tumor – First report of Crohn's disease in the kidney

Crohn's disease is a granulomatous inflammatory bowel disease with characteristic histopathological findings. Any part of the gastrointestinal tract can be involved, but it is extremely rare to find cases when it spreads beyond the intestinal structures. We present a case of a woman with extraintestinal Crohn's disease in the left kidney, mimicking renal tumor. Rare cases reported in the literature describe involvement of the inner ear, the nasal cavity, supraglottic structures, glottis, and skin, but not that of the kidneys.

A 51-year-old female patient with a previous history of two colonic resections due to Crohn's disease presented in January 2010 actually with rectovaginal fistula. She had a 20yrs history of Crohn's disease. There was no response to steroids, and azathioprin was not tolerated because of hypertensive events. Anti-TNF-α therapy was considered. CT-enteroclysis was performed to evaluate the small bowel involvement before starting biological therapy, and a mass lesion of the left kidney was revealed. Ultrasound-guided fine needle biopsy was considered, but nephrectomy was carried out. Histological examination of the surgical specimen surprisingly described a typical granulomatous inflammatory pattern, and excluded malignancy. Our case is the first presentation of Crohn's disease localized in the kidney. Fine needle biopsy could have made the nephrectomy avoidable, which emphasizes the importance of preoperative biopsy taking.