International Urology and Nephrology 24 (4), pp. 347--351 (1992)
Multiple Fibroepithelial Polyps of the Renal Pelvis and Calyces" A Case Report T. ALKIBAY,* (~. ATAOGLU,** T. TECIMER,** S. I,SIK,*** I. BOZKIRLI* Departments of *Urology, **Pathology and ***Radiology, Faculty of Medicine, Gazi University, Ankara, Turkey (Accepted August 16, 1991) Fibroepithelial polyp of the renal pelvis is an extremely rare entity. We report a case of multiple fibroepithelial polyps of the renal pelvis and calyces and discuss this rare and confusing condition with its clinical, radiological and pathological findings.
Fibroepithelial polyps are benign tumours of mesodermal origin that arise in the wail of the renal pelvis [1 ], ureter [2], bladder and urethra [3]. These benign tumours are reported in all age groups [3] and their most common occurrence site in adults is the upper urinary tract [1, 4]. There are numerous reports offibroepithelial polyps in the ureter [2, 5-9], but to our knowledge there are only 14 reported cases in the renal pelvis and/or calyces [1, 4, 10-20]. We herein report another case with multiple fibroepithelial polyps of the renal collecting system and discuss this rare and confusing benign tumour with its clinical, radiological and pathologic findings. Case report A 38-year-old female patient was hospitalized for right flank pain and right abdominal mass. Intravenous urography showed a poorly visualizing enlarged right kidney shadow. Computerized tomography scan of the abdomen demonstrated an excessively enlarged kidney which particularly grew in the anterior direction. A tumour of heterogeneous density was observed to fill the entire renal pelvis and calyceal regions (Fig. 1). Multiple cystic pouches were noticed in adjacent areas in the enhanced scans and contrast material was identified inside the collecting system indicating that filtration function was still present. However, the lesion did not show a significant contrast by itself (Fig. 2). Right nephroureterectomy was performed with a preoperative diagnosis of transitional renal cell turnout and the material was sent for pathological examination. The material submitted for histopathological study consisted of a right nephrectomy specimen and an ureter. The nephrectomy specimen measured 15 • 13 cm and included perirenal adipose tissue. When sectioned, the calyces were found to be dilated and numerous polyps were apparently arising from the VSP, Utrecht Akaddmiai Kiad6, Budapest
348
Alkibay et aL : Fibroepithelial polyps
renal pelvis and calyces (Fig. 3), The largest polyp measured 5 x 1 cm and the polyps had papillary projections. All of the polyps had relatively smooth outlines and were firm and greyish-white in colour. The thickness of the cortex varied from 0.5 to 1 cm. There was apparently no gross pathology in the ureter. Various
Fig. 1. Tumour of heterogeneous density filling the entire renal collecting system
Fig. 2, Contrast medium (arrow) indicating renal function International Urolo9y and Nephrolooy 24, 1992
Alkibay et al. : Fibroepithelial polyps
349
Fig. 3. Macroscopic appearance of kidney with multiple polyps (arrows) and dilated calyces
Fig. 4. Polyps covered by transitional epithelium. The stroma shows foci of inflammatory cells consisting mainly of lymphocytes and plasma cells. Haematoxylin and eosin, X 80
samples were obtained from the polyps, kidney and ureter and the sections were dehydrated through graded alcohols and embedded in paraffin blocks. Sections of 5 # thickness were prepared from these blocks and subsequently stained with haematoxylin and eosin. Microscopic examination showed that the polyps were 2
International Urology and Nephrology 24, 1992
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Alkibay et aL ." Fibroepithelial polyps
covered with transitional epithelium and had a relatively loose stroma containing foci of inflammatory cells consisting mainly of lymphocytes and plasma ceils (Fig. 4). There were also increased numbers of blood vessels, some of them dilated. There were no atypical changes in the covering epithelium. In the other parts of the kidney and ureter there was also a nonspecific mononuclear inflammatory reaction. It was concluded that the renal lesion was consistent with multiple fibroepithelial polyps of the renal pelvis and calyces.
Discussion
Fibroepithelial polyp of the renal pelvis and/or calyces is an extremely rare mesodermal tumour. As observed in our case, histology always reveals a fibrous tissue covered with transitional epithelium that is singly or multiply layered and the stroma shows oedema and sometimes chronic mononuclear infiltration [4, 21 ]. Several theories concerning the pathogenesis of fibroepithelial polyps have been proposed. Infection [7], chronic irritation and urinary lithiasis [20], obstruction [7], hormonal imbalance [22], allergic factors [23, 24] and developmental defects [25] have been suggested but the aetiology of these lesions is still obscure. Analysis of the previously reported 14 cases reveals that these benign tumours have a predilection for women over man and commonly occur in the third or fourth decade [1, 4]. Predilection for the right kidney has also been noted [1, 4]. Flank pain, dysuria, frequency, fever, abdominal mass, haematuria and cloudy urine have been reported as symptoms and signs of the previous cases [1], but pain and haematuria have been the most common of all [I, 4]. Radiologically, urographies of the previously reported cases have shown pyelectasis, calyectasis, hydronephrosis, filling defects and nonvisualization of the affected side [1, 4, 18, 19]. Retrograde pyelography has been helpful for showing the filling defects [1]. Similar to our case, de Jonge et al. have clearly shown intrapelvic tumours with computerized tomography scans [4]. Most of the previously reported cases have been misdiagnosed as transitional cell tumours [4, 11, 14] and one case was treated as a radiolucent stone [19]. In many cases either nephrectomy or nephroureterectomy has been done [11, 12, 13, 14, 18, 19] and the diagnosis was ascertained on pathological examination. Our case illustrated most of the typical clinical and radiological features of fibroepithelial polyps, but because of the rarity of this entity it was also handled as a transitional cell tumour. Conservatism and a wide local excision of fibroepithelial polyps are advocated [1, 4, 20], and only one recurrence has been observed after local resection [4]. In conclusion: When a right renal pelvic filling defect is encountered in a female patient in her third or fourth decade, fibroepithelial polyp should be considered at the differential diagnosis in order to avoid an unnecessary nephrectomy.
International Urology and Nephrology 24, 1992
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351
References 1. Wolgel, C. D., Parris, A. C., Mitty, H. A., Schapira, H. E. : Fibroepithelial polyp of renal pelvis. Urology, 19, 436 (1982). 2. Van Poppel, H., Nuttin, B., Oyen, R., Stessens, R., Van Damme, B., Verduyn, H.: Fibroepithelial polyps of the ureter. Fur. UroL, 12, 174 (1986). 3. Musselman, P., Kay, R. : The spectrum of urinary tract fibroepithelial polyps in children. J. UroL, 136, 476 (1986). 4. de Jonge, J. P. A., von Kortfleisch, D., Blessing, M. H., Str~3ker, W. : Fibroepithelioma of the renal pelvis. Urol. Int., 43, 56 (1988). 5. Bahnson, R. R., Blum, M. D., Carter, M. T.: Fibroepithelial polyps of the ureter. J. Urol., 132, 343 (1984). 6. Banner, M. P., Pollack, H. M. : Fibrous ureteral polyps. Radiology, 130, 73 (1979). 7. Berger, R. M., Lebowitz, J. M., Carrol, A.: Ureteral polyps presenting as ureteropelvic junction obstruction in children. J. Urol., 128, 805 (1982). 8. Ney, C., Yerubandi, S., Levy, J.: Fibroureteral polyps of the ureter. Urology, 21, 393 (1983). 9. Williams, P. R., Feggetter, J., Miller, R. A., Wickham, J. E. A. : The diagnosis and management of benign fibrous ureteric polyps. Br. J. Urol., 52, 253 (1980). 10. Bernier, L., Bedard, A., Narcisse, R. : Fibrome du bassinet. Can. J. Sur#., 13, 315 (1970). 11. Cassirnally, K. A. I. : Fibrorna filling the renal pelvis : A report of a case. Can. J. Sur#., 14, 350 (1971). 12. Evans, A. T., Stevens, R. K. : Fibroepithelial polyps of ureter and renal pelvis: A case report. J. UroL, 86, 313 (1961). 13. HiJsch, P.: Ober einen Fall vom Myxom des Nierenbeckens. Z. UroL, 42, 286 (1942). 14. Immergut, S., Cottler, Z. R. : Intrapelvic fibroma. J. UroL, 66, 673 (1951). 15. Ritchey, M. L., McDonald, E. C., Novicki, D. E.: Fibroepithelial polyp in calyceal diverticulum. J. Urol., 133, 79 (1985). 16. Shucksmith, H. S. : Fibroma of the renal pelvis. Br. J. UroL, 35, 485 (1952). 17. Pimental, M. C., Pedrosa, C. S., Silmi, A., Nacarino, U : Giant fibrous polyp of a calix. Urol. RadioL, 7, 51 (1985). 18. Edelman, R., Kim, E. S., Bard, R. H.: Benign fibroepithelial polyp of the renal pelvis. Br. J. Urol., 54, 321 (1982). 19. Blank, C., Lissmer, L., Kaneti, J., Glikman, L., Moroko, I., Krugliak, L. : Fibroepithelial polyp of the renal pelvis. J. Urol., 137, 962 (1987). 20. Murshidi, M. S.: Calculous disease and its relationship to fibroepithelial polyps of the renal pelvis and ureter. Acta UroL Belg., 56, 47 (1988). 21. Millan, J. C.: Tumors of the kidney, In: Gary S. Hill (ed.): Uropathology. 1989, p. 745. 22. Debruyne, F. M. J., Moonen, W. A., Daenekindt, A. A., Daleare, K. P. J. : Fibroepithelial polyp of the ureter. Urology, 16, 355 (1980). 23. Desbiens, R., Thibert, R., Belanger, P. M., Roinescu, I., Fleurent, B.: Polypes b6nins de uret6re. J. UroL NephroL, 84, 17 (1978). 24. Dufr6not, A., Aubert, J. : Le polype fireux de l'uret6re. Acta UroL Belg., 47, 20 (1979). 25. Soderdahl, D. W., Schuster, S. R.: Benign fibroepithelial polyp in the newborn JAMA, 207, 1714 (1969).
2*
International Urology and Nephrology 24, 1992
Multiple Fibroepithelial Polyps of the Renal Pelvis and Calyces" A Case Report T. ALKIBAY,* (~. ATAOGLU,** T. TECIMER,** S. I,SIK,*** I. BOZKIRLI* Departments of *Urology, **Pathology and ***Radiology, Faculty of Medicine, Gazi University, Ankara, Turkey (Accepted August 16, 1991) Fibroepithelial polyp of the renal pelvis is an extremely rare entity. We report a case of multiple fibroepithelial polyps of the renal pelvis and calyces and discuss this rare and confusing condition with its clinical, radiological and pathological findings.
Fibroepithelial polyps are benign tumours of mesodermal origin that arise in the wail of the renal pelvis [1 ], ureter [2], bladder and urethra [3]. These benign tumours are reported in all age groups [3] and their most common occurrence site in adults is the upper urinary tract [1, 4]. There are numerous reports offibroepithelial polyps in the ureter [2, 5-9], but to our knowledge there are only 14 reported cases in the renal pelvis and/or calyces [1, 4, 10-20]. We herein report another case with multiple fibroepithelial polyps of the renal collecting system and discuss this rare and confusing benign tumour with its clinical, radiological and pathologic findings. Case report A 38-year-old female patient was hospitalized for right flank pain and right abdominal mass. Intravenous urography showed a poorly visualizing enlarged right kidney shadow. Computerized tomography scan of the abdomen demonstrated an excessively enlarged kidney which particularly grew in the anterior direction. A tumour of heterogeneous density was observed to fill the entire renal pelvis and calyceal regions (Fig. 1). Multiple cystic pouches were noticed in adjacent areas in the enhanced scans and contrast material was identified inside the collecting system indicating that filtration function was still present. However, the lesion did not show a significant contrast by itself (Fig. 2). Right nephroureterectomy was performed with a preoperative diagnosis of transitional renal cell turnout and the material was sent for pathological examination. The material submitted for histopathological study consisted of a right nephrectomy specimen and an ureter. The nephrectomy specimen measured 15 • 13 cm and included perirenal adipose tissue. When sectioned, the calyces were found to be dilated and numerous polyps were apparently arising from the VSP, Utrecht Akaddmiai Kiad6, Budapest
348
Alkibay et aL : Fibroepithelial polyps
renal pelvis and calyces (Fig. 3), The largest polyp measured 5 x 1 cm and the polyps had papillary projections. All of the polyps had relatively smooth outlines and were firm and greyish-white in colour. The thickness of the cortex varied from 0.5 to 1 cm. There was apparently no gross pathology in the ureter. Various
Fig. 1. Tumour of heterogeneous density filling the entire renal collecting system
Fig. 2, Contrast medium (arrow) indicating renal function International Urolo9y and Nephrolooy 24, 1992
Alkibay et al. : Fibroepithelial polyps
349
Fig. 3. Macroscopic appearance of kidney with multiple polyps (arrows) and dilated calyces
Fig. 4. Polyps covered by transitional epithelium. The stroma shows foci of inflammatory cells consisting mainly of lymphocytes and plasma cells. Haematoxylin and eosin, X 80
samples were obtained from the polyps, kidney and ureter and the sections were dehydrated through graded alcohols and embedded in paraffin blocks. Sections of 5 # thickness were prepared from these blocks and subsequently stained with haematoxylin and eosin. Microscopic examination showed that the polyps were 2
International Urology and Nephrology 24, 1992
350
Alkibay et aL ." Fibroepithelial polyps
covered with transitional epithelium and had a relatively loose stroma containing foci of inflammatory cells consisting mainly of lymphocytes and plasma ceils (Fig. 4). There were also increased numbers of blood vessels, some of them dilated. There were no atypical changes in the covering epithelium. In the other parts of the kidney and ureter there was also a nonspecific mononuclear inflammatory reaction. It was concluded that the renal lesion was consistent with multiple fibroepithelial polyps of the renal pelvis and calyces.
Discussion
Fibroepithelial polyp of the renal pelvis and/or calyces is an extremely rare mesodermal tumour. As observed in our case, histology always reveals a fibrous tissue covered with transitional epithelium that is singly or multiply layered and the stroma shows oedema and sometimes chronic mononuclear infiltration [4, 21 ]. Several theories concerning the pathogenesis of fibroepithelial polyps have been proposed. Infection [7], chronic irritation and urinary lithiasis [20], obstruction [7], hormonal imbalance [22], allergic factors [23, 24] and developmental defects [25] have been suggested but the aetiology of these lesions is still obscure. Analysis of the previously reported 14 cases reveals that these benign tumours have a predilection for women over man and commonly occur in the third or fourth decade [1, 4]. Predilection for the right kidney has also been noted [1, 4]. Flank pain, dysuria, frequency, fever, abdominal mass, haematuria and cloudy urine have been reported as symptoms and signs of the previous cases [1], but pain and haematuria have been the most common of all [I, 4]. Radiologically, urographies of the previously reported cases have shown pyelectasis, calyectasis, hydronephrosis, filling defects and nonvisualization of the affected side [1, 4, 18, 19]. Retrograde pyelography has been helpful for showing the filling defects [1]. Similar to our case, de Jonge et al. have clearly shown intrapelvic tumours with computerized tomography scans [4]. Most of the previously reported cases have been misdiagnosed as transitional cell tumours [4, 11, 14] and one case was treated as a radiolucent stone [19]. In many cases either nephrectomy or nephroureterectomy has been done [11, 12, 13, 14, 18, 19] and the diagnosis was ascertained on pathological examination. Our case illustrated most of the typical clinical and radiological features of fibroepithelial polyps, but because of the rarity of this entity it was also handled as a transitional cell tumour. Conservatism and a wide local excision of fibroepithelial polyps are advocated [1, 4, 20], and only one recurrence has been observed after local resection [4]. In conclusion: When a right renal pelvic filling defect is encountered in a female patient in her third or fourth decade, fibroepithelial polyp should be considered at the differential diagnosis in order to avoid an unnecessary nephrectomy.
International Urology and Nephrology 24, 1992
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351
References 1. Wolgel, C. D., Parris, A. C., Mitty, H. A., Schapira, H. E. : Fibroepithelial polyp of renal pelvis. Urology, 19, 436 (1982). 2. Van Poppel, H., Nuttin, B., Oyen, R., Stessens, R., Van Damme, B., Verduyn, H.: Fibroepithelial polyps of the ureter. Fur. UroL, 12, 174 (1986). 3. Musselman, P., Kay, R. : The spectrum of urinary tract fibroepithelial polyps in children. J. UroL, 136, 476 (1986). 4. de Jonge, J. P. A., von Kortfleisch, D., Blessing, M. H., Str~3ker, W. : Fibroepithelioma of the renal pelvis. Urol. Int., 43, 56 (1988). 5. Bahnson, R. R., Blum, M. D., Carter, M. T.: Fibroepithelial polyps of the ureter. J. Urol., 132, 343 (1984). 6. Banner, M. P., Pollack, H. M. : Fibrous ureteral polyps. Radiology, 130, 73 (1979). 7. Berger, R. M., Lebowitz, J. M., Carrol, A.: Ureteral polyps presenting as ureteropelvic junction obstruction in children. J. Urol., 128, 805 (1982). 8. Ney, C., Yerubandi, S., Levy, J.: Fibroureteral polyps of the ureter. Urology, 21, 393 (1983). 9. Williams, P. R., Feggetter, J., Miller, R. A., Wickham, J. E. A. : The diagnosis and management of benign fibrous ureteric polyps. Br. J. Urol., 52, 253 (1980). 10. Bernier, L., Bedard, A., Narcisse, R. : Fibrome du bassinet. Can. J. Sur#., 13, 315 (1970). 11. Cassirnally, K. A. I. : Fibrorna filling the renal pelvis : A report of a case. Can. J. Sur#., 14, 350 (1971). 12. Evans, A. T., Stevens, R. K. : Fibroepithelial polyps of ureter and renal pelvis: A case report. J. UroL, 86, 313 (1961). 13. HiJsch, P.: Ober einen Fall vom Myxom des Nierenbeckens. Z. UroL, 42, 286 (1942). 14. Immergut, S., Cottler, Z. R. : Intrapelvic fibroma. J. UroL, 66, 673 (1951). 15. Ritchey, M. L., McDonald, E. C., Novicki, D. E.: Fibroepithelial polyp in calyceal diverticulum. J. Urol., 133, 79 (1985). 16. Shucksmith, H. S. : Fibroma of the renal pelvis. Br. J. UroL, 35, 485 (1952). 17. Pimental, M. C., Pedrosa, C. S., Silmi, A., Nacarino, U : Giant fibrous polyp of a calix. Urol. RadioL, 7, 51 (1985). 18. Edelman, R., Kim, E. S., Bard, R. H.: Benign fibroepithelial polyp of the renal pelvis. Br. J. Urol., 54, 321 (1982). 19. Blank, C., Lissmer, L., Kaneti, J., Glikman, L., Moroko, I., Krugliak, L. : Fibroepithelial polyp of the renal pelvis. J. Urol., 137, 962 (1987). 20. Murshidi, M. S.: Calculous disease and its relationship to fibroepithelial polyps of the renal pelvis and ureter. Acta UroL Belg., 56, 47 (1988). 21. Millan, J. C.: Tumors of the kidney, In: Gary S. Hill (ed.): Uropathology. 1989, p. 745. 22. Debruyne, F. M. J., Moonen, W. A., Daenekindt, A. A., Daleare, K. P. J. : Fibroepithelial polyp of the ureter. Urology, 16, 355 (1980). 23. Desbiens, R., Thibert, R., Belanger, P. M., Roinescu, I., Fleurent, B.: Polypes b6nins de uret6re. J. UroL NephroL, 84, 17 (1978). 24. Dufr6not, A., Aubert, J. : Le polype fireux de l'uret6re. Acta UroL Belg., 47, 20 (1979). 25. Soderdahl, D. W., Schuster, S. R.: Benign fibroepithelial polyp in the newborn JAMA, 207, 1714 (1969).
2*
International Urology and Nephrology 24, 1992
