896 Edited1.pdf 906 | Case Report Renal Replacement Lipomatosis with Coexistent Papillary Renal Cell Carcinoma, Renal Tubulopapillary Adenomatosis, and Xanthogranulomatous Pyelonephritis An Extremely Rare Association and Possible Pathoge- netic Correlation Prerna Arora,1 Seema Rao,1 Nita Khurana,1 Vinod Kumar Ramteke2 Keywords: pyelonephritis, papillary renal cell carcinoma, lipomatosis INTRODUCTION Renal replacement lipomatosis (RRL) is a rare condition, which is characterized by diffuse replacement of renal parenchyma, sinus, and hilum with adipose tissue.(1) It is thought to be associated with physiological as well as several pathological (2,3) In the present case, we found coexistence of RRL with papillary renal cell carcinoma (PRCC). Further- more, renal tubulopapillary adenomatosis, xanthogranulomatous pyelonephritis (XGP), and multiple renal calculi were also found. A brief review of literature along with probable patho- genesis of such a rare coexistence is presented. CASE REPORT years. Physical examination was unremarkable. Urinalysis showed 30 to 35 red blood cells/ hpf and 20 to 25 pus cells/hpf. An abdominal ultrasonography revealed multiple calculi in the right kidney along with a hypoechoic mass near the upper pole with alteration of vascular- ity, suggestive of RCC or adrenal mass. Contrast-enhanced computed tomography revealed small contracted right kidney. The perinephric fat was proliferating and compressing pa- tissue mass was seen at the superior pole suggestive of RCC or oncocytoma. Left kidney was normal in morphology and echotexture. Corresponding Author: Seema Rao, MD Department of Pathology, Maulana Azad Medical Col- lege, New Delhi, 110002, India Tel: +91 986 855 1374 Fax: +91 2658 8641 E-mail: seemarao1974@ yahoo.co.in Received February 2011 Accepted July 2011 1Department of Pathology, Maulana Azad Medical Col- lege, New Delhi, 110002, India 2Department of Surgery, Maulana Azad Medical Col- lege, New Delhi, 110002, India CASE REPORT 907Vol. 10 | No. 2 | Spring 2013 |U R O LO G Y J O U R N A L by adipose tissue with small foci of residual atrophied renal parenchyma (Figure 1). There was dilatation of pelvical- yceal system with presence of multiple stones in the caly- - tiple small yellow-colored nodules, largest one of which Microscopic examination from yellow nodules showed foci of tubulopapillary adenomatosis (Figure 2). Sections from papillary area showed PRCC (Figure 3A). Adjacent areas revealed thyroidization of tubules along with diffuse inter- and xanthoma cells, suggestive of XGP (Figures 2 and 3B). DISCUSSION Renal replacement lipomatosis is a benign condition where renal parenchyma, which in turn becomes atrophic. It can involve the renal sinus, renal hilum, and perirenal space to variable extent.(1) - hilum, and/or perirenal space include obesity, Cushing’s syndrome, corticosteroid excess, or be idiopathic. How- ever, the preservation of renal parenchyma in such cases distinguishes these entities from RRL.(4,5) Renal replace- ment lipomatosis is usually secondary to renal calculus and renal tuberculosis, occasionally occurs after renal infarction or may be idiopathic. there was no history suggestive of Cushing syndrome or corticosteroid and anti-tuberculosis drug intake. diagnosis in RRL and is considered to be superior to ultra- sonography, which is not very sensitive for detecting fatty proliferation.(7) Furthermore, CT scan is considered to be the best imaging modality to differentiate RRL from other fat-rich lesions, such as renal angiomyolipoma, retroperito- neal lipoma, and liposarcoma.(8) Renal replacement lipomatosis is frequently associated with XGP. Both share several similarities in terms of possible Coexistent of Lipomatosis with RCC | Arora et al Figure 1. Gross photograph of the kidney showing fatty replace- ment of renal tissue, renal calculi (single arrow), and part of atrophic cystic kidney (double arrows); Inset: Solid foci of papil- lary RCC (arrow). Figure 2. Microphotograph of the kidney showing multiple foci of tubulopapillary adenomatosis along with changes of chronic pyelonephritis (Hematoxylin and Eosin stain, ×4). Figure 3. (A) Microphotograph showing papillary RCC with psammomatous calcification (Hematoxylin and Eosin stain, 10×); (B) Kidney showing xanthogranulomatous pyelonephritis com- prising foamy cells along with inflammatory cells (Hematoxylin and Eosin stain, ×20) 908 | - induction of fatty proliferation, which in turn compensates the loss of renal tissue, thus leading to RRL.(9,10) Although there are only limited data available, it is known that the kidneys harboring RCC could reveal various pre- malignant lesions ranging from dysplasia to adenoma.(11,12) in PRCC. In a study of 542 nephrectomy specimens, 7% showed papillary adenoma, out of which 47% arose in the setting of PRCC and 15.7% in association with clear cell RCC.(12) Adenomas associated with PRCC are usually mul- tiple.(12) The present subject had PRCC with presence of multiple tubulopapillary adenomatosis, thereby corroborat- ing adenoma-carcinoma sequence. Furthermore, our patient had the unique coexistence of RRL with XGP, probably secondary to renal calculi. In conclusion, apart from the novelty of being a rare case, predisposing factors and pathogenesis of RRL and PRCC. We hope more urologists, radiologists, and pathologists be- come aware of this unique entity for its early diagnosis and proper management. CONFLICT OF INTEREST None declared. REFERENCES 1. Setty NHA, Uma K, Narvekar VN, Desai RS. Bilateral idiopathic replacement lipomatosis of the kidney with posterior mediastinal lipomatosis. Indian J Radiol Imaging. 2002;12:251-2. 2. Kuthman A. Replacement lipomatosis of the kidney. Surg Gynecol Obstet. 1931;52:690-701. 3. Kiris A, Kocakoc E, Poyraz AK, Dagli F, Boztosun Y. Xan- thogranulomatous pyelonephritis with nephrocutanous fistula and coexisting renal replacement lipomatosis: the report of a rare case. Clin Imaging. 2005;29:356-8. 4. Ambos MA, Bosniak MA, Gordon R, Madayag MA. Replace- ment lipomatosis of the kidney. AJR Am J Roentgenol. 1978;130:1087-91. 5. Hurwitz RS, Benjamin JA, Cooper JF. Excessive proliferation of peripelvic fat of the kidney. Urology. 1978;11:448-56. 6. Peacock AH, Balle A. Renal Lipomatosis. Ann Surg. 1936;103:395-401. 7. Kocaoglu M, Bozlar U, Sanal HT, Guvenc I. Replacement lipomatosis: CT and MRI findings of a rare renal mass. Br J Radiol. 2007;80:e287-9. 8. Waligore MP, Stephens DH, Soule EH, McLeod RA. Li- pomatous tumors of the abdominal cavity: CT appear- ance and pathologic correlation. AJR Am J Roentgenol. 1981;137:539-45. 9. Sakata Y, Kinoshita N, Kato H, Yamada Y, Sugimura Y. Coex- istence of renal replacement lipomatosis with xanthogran- ulomatous pyelonephritis. Int J Urol. 2004;11:44-6. 10. Prasad KK, Pandey R, Kathuria M, Pradhan PK. Co-existent massive renal replacement lipomatosis and xanthogranu- lomatous pyelonephritis--a case report. Indian J Pathol Microbiol. 2003;46:674-5. 11. Van Poppel H, Nilsson S, Algaba F, et al. Precancerous le- sions in the kidney. Scand J Urol Nephrol Suppl. 2000;136- 65. 12. Wang KL, Weinrach DM, Luan C, et al. Renal papillary adenoma--a putative precursor of papillary renal cell carci- noma. Hum Pathol. 2007;38:239-46. Case Report