INFLAMMATORY MYOFIBROBLASTIC TUMOR ASSOCIATED WITH RENAL CELL CARCINOMA ERIC S. GWYNN and PETER E. CLARK ABSTRACT A 46-year-old man was referred for evaluation of a 13-cm renal mass. Right radical nephrectomy was performed. Pathologic evaluation revealed inflammatory myofibroblastic tumor (IMT) and renal cell carci- noma. To our knowledge, only 28 cases of IMT associated with the kidney have been reported in published studies. This is the first reported case of IMT associated with malignancy in the urogenital tract. Some investigators have suggested that biopsy-proven IMT can be managed conservatively, but the findings of this report have demonstrated the need for radical nephrectomy in this patient population to rule out associated malignancy. UROLOGY 66: 880.e7–880.e9, 2005. © 2005 Elsevier Inc. I nflammatory myofibroblastic tumor (IMT) is a rare pathologic entity composed of myofibro- blasts and an accompanying inflammatory infil- trate. First described in the lung, IMT has been described as a benign lesion that mimics malig- nancy. In the urogenital tract, IMT most com- monly occurs in the bladder. However, involve- ment of the upper tract has been reported. We describe a rare case of IMT in a 46-year-old man that encased a focus of renal cell carcinoma. Thus, even in biopsy-proven IMT, the optimal treatment should be surgical resection. CASE REPORT A 46-year-old man was referred to our institution with a right renal mass. He had been evaluated for a chief complaint of abdominal discomfort with associated gastrointestinal symptoms and no uro- logic problems. His physical examination and fam- ily history were unremarkable. All laboratory val- ues were within normal limits, and the urinalysis was positive for trace blood. Voided urine cytology was negative for malignancy. Renal ultrasonogra- phy revealed a 13-cm heterogeneous right renal mass with accompanying hydronephrosis. Addi- tional imaging with computed tomography dem- onstrated a 13  12  10-cm heterogeneous mass with a central cystic focus and apparent breach of the fat plane between the colon and the kidney. Neither renal vein invasion nor inferior vena cava extension was evident on magnetic resonance im- aging (Fig. 1). On the basis of the clinical and ra- diologic findings, a malignancy such as renal cell carcinoma was suspected, and right radical ne- phrectomy was performed. This disclosed a 23  21  12-cm tan-brown mass involving the right colon and densely adherent to the duodenum, as well as the psoas fascia. Right hemicolectomy was performed en bloc with the kidney and primary reanastomosis. Histologic examination revealed the bulk of the tumor to contain spindle cells ad- mixed with collagen, lymphocytes, and plasma cells (Fig. 2). This pattern was consistent with IMT. Immunostaining for ALK-1 was negative (see Comment section). Approximately 20% of the specimen was composed of normal kidney. Also isolated within the mass was a 7-cm focus of cystic clear cell renal cell carcinoma. No histologic evi- dence of extension into the renal vein, artery, or ureter was found. No neoplasm was identified in the colon. This patient was doing well without ev- idence of recurrence 12 months after surgery. COMMENT IMT is known by several names, including in- flammatory pseudotumor, pseudosarcomatous fibromyxoid tumor, fibrous xanthoma, and plasma cell granuloma. Its original description was of a tumor in the lung but several extrapul- From the Department of Urology, Wake Forest University, Win- ston-Salem, North Carolina Address for correspondence: Eric S. Gwynn, M.D., Department of Urology, Wake Forest University, Medical Center Boulevard, Winston-Salem, NC 27157. E-mail: wakeurodoc@yahoo.com Submitted: January 11, 2005, accepted (with revisions): March 24, 2005 CASE REPORT © 2005 ELSEVIER INC. 0090-4295/05/$30.00 ALL RIGHTS RESERVED doi:10.1016/j.urology.2005.03.065 880.e7