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Renal Cell Carcinoma with Osteosarcomatous Differentiation Simulating Staghorn Calculus: A Case Report and Literature Review
00'.22-5:34 7 /94/!5 lG-1607 $0:1.00/0 \'ol. 151. 1601-1609, ,June 1994
THE ,Jot:RNAL OF UROLOGY
Printed in
Copyright,(: 1994 by AMERICAN UROLOGICAL ASSOCIATION, INC.
RENAL CELL CARCINOMA WITH OSTEOSARCOMATOUS DIFFERENTIATION SIMULATING STAGHORN CALCULUS: A CASE REPORT AND LITERATURE REVIEW K. CHEE SAW, RICHARD Y. BALL,* NAVID H. KHAN, JOHN R. PILLING, IAN EARDLEY AND MICHAEL H. ASHKEN From the Departments of Urology, Histopathology and Radiology, Norfolk and Norwich Hospital, Norwich, Norfolk, United Kingdom
ABSTRACT
We report a case of renal cell carcinoma that showed extensive osteosarcomatous differentiation and simulated a staghorn calculus clinically and radiologically. The literature on osteosarcomatous differentiation in renal cell carcinoma is reviewed. KEY WORDS: kidney neoplasms, osteosarcoma, carcinosarcoma, calculi
Sarcomatous differentiation in renal cell carcinoma is uncommon 1 ·" and osteosarcomatous differentiation is exceptionally rare. 1 ·:1 Staghorn calculus and renal cell carcinoma may occur in the same kidney, and cause diagnostic difficulty.4·s We report a case of renal cell carcinoma that showed extensive osteosarcomatous differentiation, and simulated a staghorn calculus clinically and radiologically.
CASE REPORT
A 69-year-old woman presented with a 3-week history of back pain and hematuria. The pain, which was mainly in the left lower back and radiated to the suprapubic region, was severe, sharp and worsened by movement. She had recently become lethargic and anorexic, and weight had decreased by 4 kg. She was nauseated and vomited before hospitalization. Abdominal examination revealed no abnormality but tenderness in the left loin. Cardiovascular, respiratory and neurological evaluations were normal. Complete blood count, serum urea, electrolytes, calcium and liver function tests were normal except for a normochromic, normocytic anemia with hemoglobin of 10.5 gm./dl. (normal 11.5 to 16.5), serum alkaline phosphatase 179 IU /1. (normal 30 to 120), gamma glutamyl transferase 44 IU /1. (normal 2 to 35) and alanine aminotransferase 26 IU/1. (normal 2 to 24). Urine contained 50 million erythrocytes per L but no leukocytes or casts and it was sterile on culture. Abdominal x-ray showed left renal calcification (fig. 1). Ultrasound revealed a small left kidney with a calcified mass that filled the collecting system. A 99 mtechnetium-dimercaptosuccinic acid scan showed no evidence of left renal function. Findings were consistent with a staghorn calculus in a nonfunctioning kidney. An excretory urogram performed 19 years previously was normal. Simple nephrectomy was done. A "calculus" was palpable within a small kidney. The patient was discharged home after an uneventful convalescence but rehospitalized 3 weeks later with low back and right loin pain. The lumbar spine was tender to palpation. The patient was anemic with a hemoglobin of 10.4 gm./dl., serum alkaline phosphatase 206 IU/1. and calcium 2.79 mmol./ l. (normal 2.1 to 2.6). A chest x-ray showed an elevated right hemidiaphragm with normal lung fields. Radiography of the lumbar spine and bone scans were abnormal, and consistent Accepted for publication October 29, 1993. * Requests for reprints: Norfolk and Norwich Hospital, Norwich, Norfolk NRl 3SR, United Kingdom.
with spinal metastatic disease. Despite a course of palliative radiotherapy to the lumbar spine complete paraplegia gradually developed. The condition deteriorated and the patient died 2 months after nephrectomy. No postmortem examination was performed. PATHOLOGY
The 10 X 6 X 6 cm., 158 gm. kidney showed external lobulation. The central part contained a fleshy gray and white, 6.3 X 3.8 cm. tumor that appeared to arise in close association with the pelvicaliceal system to form an imperfect cast (fig. 2). The mass diffusely permeated much of the renal parenchyma, left normal tissue at the poles, and extended into the hilus and perinephric fat. Much of the tumor was bony hard, and sawing and decalcification were needed to obtain sections for histological examination. Tumor invaded the renal vein and projected into the ureter.
FIG. 1. Plain abdominal x-ray shows large, inhomogenous, faint left renal calcification (arrows).
1607
1608
RENAL CELL CARCINOMA WITH OSTEOSARCOMATOUS DIFFERENTIATION DISCUSSION
FIG. 2. Renal tumor fills renal pelvis, forms imperfect cast and extends into proximal ureter (arrow).
Histological examination showed various patterns of tumor differentiation. A few small areas of malignant epithelial cells were consistent with poorly differentiated renal cell carcinoma (fig. 3, A). Much of the mass was composed of sarcomatous tissue made up of pleomorphic spindle-shaped cells. Part of this had a storiform pattern that resembled malignant fibrous histiocytoma and other areas had a fibrosarcomatous arrangement. Large portions of the tumor, mainly in relation to the pelvicaliceal system, were composed of plump osteoblast-like cells, and showed extensive formation of osteoid and bone (fig. 3, B ). In some areas the various elements were closely juxtaposed and appeared to merge. Immunocytochemical investigation indicated widespread reactivity for vimentin in epithelioid and spindle cell components, and focal positivity for epithelial membrane antigen. Cytokeratins were not demonstrated but internal controls, that is normal renal tubules, were positive for the different markers.
The tumor in our case was renal cell carcinoma that showed extensive sarcomatous differentiation, predominantly osteosarcomatous in type. Sarcomatous differentiation in renal cell carcinoma was first described as a separate entity in 1968 by Farrow et al. 1 It is uncommon and occurs in 1 to 1.5 % of renal parenchymal tumors. 1·2 Average patient age at diagnosis is 56 years. The tumor is usually large (mean diameter 10 cm.), soft, and gray and tan with necrotic and hemorrhagic areas. Histologically, it consists of a typical renal cell carcinoma intimately associated with a sarcomatous component that is characterized predominantly by a spindle cell pattern, which often resembles malignant fibrous histiocytoma or fibrosarcoma. 2·3 Of the sarcomatoid renal cell carcinomas 80% invade the renal pelvis. 1 These tumors usually present late and behave aggressively. Local invasion and distant metastasis are common. The disease has a poor prognosis with a median survival of approximately 6 months 2 · 3 and few patients survive more than a year. Pathological stage, degree of tumor necrosis and the proportion of sarcomatous components appear to be important prognostic factors. 3 Osteosarcomatous differentiation in renal cell carcinoma is rare even in the context of sarcomatoid renal cell carcinoma. In 3 series osteoid differentiation was found in only 5 of 92 cases of sarcomatoid carcinoma. 1-3 Apart from these 5 cases 10 cases (including our own) have been reported in the literature6-12 (see table). These patients present similarly to those with other renal tumors with loin or abdominal pain, hematuria, constitutional disturbances and a palpable mass. However, the extremely poor outlook in most cases is probably related to the aggressive nature of the tumor and its advanced stage at presentation. Radiography may provide a clue to the presence of osteosarcomatous elements. 11 Many reported cases showed calcifications within the tumor and 1 had a typical sunburst appearance. 10 The tumor in our case was present in a small nonfunctioning kidney and had a complex calcified structure, which led us to believe that it was a staghorn calculus. Renal tumors may coexist with staghorn calculi; which may present diagnostic difficulty. In all cases a calculus was evident when the kidney was removed. In our case the tumor that invaded and filled the renal pelvis was mainly osteosarcomatous in differentiation and, therefore, mimicked a staghorn calculus. Recently, primary osteosarcoma of the kidney was reported to present in a similar way. 13 The nosology of primary osteosarcoma of the kidney 14·15 should be considered when discussing osteosarcomatous differentiation in renal cell carcinoma. The diagnosis of primary
FIG. 3. A, poorly differentiated adenocarcinoma consistent with renal cell carcinoma. H & E, reduced from X250. B, sarcomatous differentiation with areas of osteoid and bone matrix at periphery of tumor. H & E, reduced from Xl25.
1609
REl'.TAL CELL CARCINOMA VVITH OSTEOSARCOMATOUS DIFFERENTJ:ATION
Renal cell carcinoma with osteosarcomatous differentiation Presentation
Reference Hou and Willis:' Case 2 Case 3* Newman and Vellios, case 17 Cecil et al 8 Moon et al9 • * Macke et al, case 1 10 • t
79-F 78-F 72-M
50-F 65-F
71-M
Mucci et al:n Case 4 Case 6 Sugarman et al 12 Present case
74-M
70-F
Side
Outcome
Pain, mass Pain, hematuria Pain, wt. loss, malaise, varicocele Pain, mass Pain, mass Hematuria, pain, fatigue, anorexia, wt. loss, mass
Lt. Rt. Lt. Lt. Rt. Rt.
Died 2 mos. Not known Died 10 mos. Died 2 mos. Alive 3 yrs. Died 22 mos.
Hematuria Hematuria
Unknown Unknown Lt. Lt.
Died Died Died Died
47-F
Hematuria, pain, mass
69-F
Pain, hematuria, lethargy, an·
2 mos. 3 mos. 5 mos. 2 mos.
orexia, wt. loss
* These cases should be included although the original authors had a different interpretation.
t This case was also published by Ferris, E. J., Harmon, B. H., Tonkin, I. L., Becker, G. J., Edeiken, B. S., Pfister, R. G. and Osborn, A. G.: Image interpretation session. Case 4. Radiographies, 9: 85, 1989.
renal osteosarcoma requires the absence of epithelial elements in the tumor after extensive sampling,6 and the use of electron microscopy 10 and immunocytochemical methods.'3, 14 ' 15 Some re· ported cases of primary renal osteosarcomas were not sampled sufficiently to exclude a small focus of renal cell carcinoma and even fewer had electron microscopy and immunocytochemical evaluations performed. Even if these studies were done some putative renal osteosarcoma may have originated as sarcomatoid renal cell carcinoma before the sarcomatous element overran and destroyed the epithelial component. Possible explanations for the presence of sarcomatous foci in renal cell carcinoma are metaplastic differentiation within the carcinoma, initial malignant transformation of a single primi· tive stem cell with the potential to differentiate along epithelial and mesenchymal pathways, simultaneous occurrence of separate but related carcinoma and sarcoma, and later development of sarcoma from the stroma of preexisting carcinoma. The pathogenesis of this disease is still unknown but the first of these explanations, which was advocated by Farrow et al, 1 currently seems to be the most acceptable. It is supported by the presence of epithelial characteristics evident in the sarcomatous areas on electron microscopy.rn Immunocytochemical studies could conceivably shed light on this problem but were uninformative in our case. In conclusion, osteosarcomatous differentiation of malignant tumor in the kidney is extremely rare and associated with a dismal prognosis. Exceptionally, it may present in a manner that mimics a staghorn calculus, which leads to confusion in diagnosis.
REFERENCES
l. Farrow, G. M., Harrison, E. G., Jr. and Utz, D. C.: Sarcomas and sarcomatoid and mixed malignant tumors of the kidney in adults-part III. Cancer, 22: 556, 1968.
2. Tomera, K. M., Farrow, G. M. and Lieber, M. M.: Sarcomatoid renal carcinoma. J. Urol., 130: 657, 1983. 3. Ro, J. Y., Ayala, A. G., Sella, A., Samuels, M. L. and Swanson, D. A.: Sarcomatoid renal cell carcinoma: clinicopathologic. A study of 42 cases. Cancer, 59: 516, 1987. 4. Oesterling, J.E., Kerr, L.A. and Segura, J. W.: Branched, struvite calculus and clear cell carcinoma in same kidney. Rare condition with significant implications for management. Urology, 36: 273, 1990. 5. Cowley, J. P., Connolly, C. E., Hehir, M. and O'Beirn, S. F.: Renal carcinoma with staghorn calculus, perinephric abscess, and xanthogranulomatous pyelonephritis in same kidney. Subcutaneous abscess of thigh as initial presentation. Urology, 21: 635, 1983. 6. Hou, L. T. and Willis, R. A.: Renal carcino-sarcoma, true and false. J. Path. Bacteriol., 85: 139, 1963. 7. Newman, D. and Vellios, F.: Adult carcinosarcoma (adult Wilms' tumor) of the kidney. Amer. J. Clin. Path., 42: 45, 1964. 8. Cecil, B., Woodard, B., Mickey, D. D. and Pizzo, S.: Renal carcinosarcoma. Ultrastructure and transplantation into athymic mice. Arch. Path. Lab. Med., 104: 276, 1980. 9. Moon, T. D., Dexter, D. F. and Morales, A.: Synchronous inde· pendent primary osteosarcoma and adenocarcinoma of kidney. Urology, 21: 608, 1983. 10. Macke, R. A., Hussain, M. B., Imray, T. J., Wilson, R. B. and Cohen, S. M.: Osteogenic and sarcomatoid differentiation of a renal cell carcinoma. Cancer, 56: 2452, 1985. 11. Mucci, B., Lewi, H. J. and Fleming, S.: The radiology of sarcomas and sarcomatoid carcinomas of the kidney. Clin. Rad., 38: 249, 1987. 12. Sugarman, I., Birch, P. and Carter, M.: Osteogenic differentiation in a sarcomatoid renal carcinoma. Brit. J. Urol., 66: 663, 1990. 13. Ah-Chong, A. K. and Yip, A. W. C.: Primary osteogenic sarcoma of the kidney presenting as staghorn calculus. Brit. J. Urol., 71: 233, 1993. 14. Eble, J. N., Young, R.H., Stiirkel, C. S. and Thoenes, W.: Primary osteosarcoma of the kidney: a report of three cases. J. Urogen. Path., l: 83, 1991. 15. O'Malley, F. P., Grignon, D. J., Shepherd, R. Rand Harker, L.A.: Primary osteosarcoma of the kidney. Report of a case studied by immunohistochemistry, electron microscopy, and DNA flow cytometry. Arch. Path. Lab. Med., 115: 1262, 1991.
THE ,Jot:RNAL OF UROLOGY
Printed in
Copyright,(: 1994 by AMERICAN UROLOGICAL ASSOCIATION, INC.
RENAL CELL CARCINOMA WITH OSTEOSARCOMATOUS DIFFERENTIATION SIMULATING STAGHORN CALCULUS: A CASE REPORT AND LITERATURE REVIEW K. CHEE SAW, RICHARD Y. BALL,* NAVID H. KHAN, JOHN R. PILLING, IAN EARDLEY AND MICHAEL H. ASHKEN From the Departments of Urology, Histopathology and Radiology, Norfolk and Norwich Hospital, Norwich, Norfolk, United Kingdom
ABSTRACT
We report a case of renal cell carcinoma that showed extensive osteosarcomatous differentiation and simulated a staghorn calculus clinically and radiologically. The literature on osteosarcomatous differentiation in renal cell carcinoma is reviewed. KEY WORDS: kidney neoplasms, osteosarcoma, carcinosarcoma, calculi
Sarcomatous differentiation in renal cell carcinoma is uncommon 1 ·" and osteosarcomatous differentiation is exceptionally rare. 1 ·:1 Staghorn calculus and renal cell carcinoma may occur in the same kidney, and cause diagnostic difficulty.4·s We report a case of renal cell carcinoma that showed extensive osteosarcomatous differentiation, and simulated a staghorn calculus clinically and radiologically.
CASE REPORT
A 69-year-old woman presented with a 3-week history of back pain and hematuria. The pain, which was mainly in the left lower back and radiated to the suprapubic region, was severe, sharp and worsened by movement. She had recently become lethargic and anorexic, and weight had decreased by 4 kg. She was nauseated and vomited before hospitalization. Abdominal examination revealed no abnormality but tenderness in the left loin. Cardiovascular, respiratory and neurological evaluations were normal. Complete blood count, serum urea, electrolytes, calcium and liver function tests were normal except for a normochromic, normocytic anemia with hemoglobin of 10.5 gm./dl. (normal 11.5 to 16.5), serum alkaline phosphatase 179 IU /1. (normal 30 to 120), gamma glutamyl transferase 44 IU /1. (normal 2 to 35) and alanine aminotransferase 26 IU/1. (normal 2 to 24). Urine contained 50 million erythrocytes per L but no leukocytes or casts and it was sterile on culture. Abdominal x-ray showed left renal calcification (fig. 1). Ultrasound revealed a small left kidney with a calcified mass that filled the collecting system. A 99 mtechnetium-dimercaptosuccinic acid scan showed no evidence of left renal function. Findings were consistent with a staghorn calculus in a nonfunctioning kidney. An excretory urogram performed 19 years previously was normal. Simple nephrectomy was done. A "calculus" was palpable within a small kidney. The patient was discharged home after an uneventful convalescence but rehospitalized 3 weeks later with low back and right loin pain. The lumbar spine was tender to palpation. The patient was anemic with a hemoglobin of 10.4 gm./dl., serum alkaline phosphatase 206 IU/1. and calcium 2.79 mmol./ l. (normal 2.1 to 2.6). A chest x-ray showed an elevated right hemidiaphragm with normal lung fields. Radiography of the lumbar spine and bone scans were abnormal, and consistent Accepted for publication October 29, 1993. * Requests for reprints: Norfolk and Norwich Hospital, Norwich, Norfolk NRl 3SR, United Kingdom.
with spinal metastatic disease. Despite a course of palliative radiotherapy to the lumbar spine complete paraplegia gradually developed. The condition deteriorated and the patient died 2 months after nephrectomy. No postmortem examination was performed. PATHOLOGY
The 10 X 6 X 6 cm., 158 gm. kidney showed external lobulation. The central part contained a fleshy gray and white, 6.3 X 3.8 cm. tumor that appeared to arise in close association with the pelvicaliceal system to form an imperfect cast (fig. 2). The mass diffusely permeated much of the renal parenchyma, left normal tissue at the poles, and extended into the hilus and perinephric fat. Much of the tumor was bony hard, and sawing and decalcification were needed to obtain sections for histological examination. Tumor invaded the renal vein and projected into the ureter.
FIG. 1. Plain abdominal x-ray shows large, inhomogenous, faint left renal calcification (arrows).
1607
1608
RENAL CELL CARCINOMA WITH OSTEOSARCOMATOUS DIFFERENTIATION DISCUSSION
FIG. 2. Renal tumor fills renal pelvis, forms imperfect cast and extends into proximal ureter (arrow).
Histological examination showed various patterns of tumor differentiation. A few small areas of malignant epithelial cells were consistent with poorly differentiated renal cell carcinoma (fig. 3, A). Much of the mass was composed of sarcomatous tissue made up of pleomorphic spindle-shaped cells. Part of this had a storiform pattern that resembled malignant fibrous histiocytoma and other areas had a fibrosarcomatous arrangement. Large portions of the tumor, mainly in relation to the pelvicaliceal system, were composed of plump osteoblast-like cells, and showed extensive formation of osteoid and bone (fig. 3, B ). In some areas the various elements were closely juxtaposed and appeared to merge. Immunocytochemical investigation indicated widespread reactivity for vimentin in epithelioid and spindle cell components, and focal positivity for epithelial membrane antigen. Cytokeratins were not demonstrated but internal controls, that is normal renal tubules, were positive for the different markers.
The tumor in our case was renal cell carcinoma that showed extensive sarcomatous differentiation, predominantly osteosarcomatous in type. Sarcomatous differentiation in renal cell carcinoma was first described as a separate entity in 1968 by Farrow et al. 1 It is uncommon and occurs in 1 to 1.5 % of renal parenchymal tumors. 1·2 Average patient age at diagnosis is 56 years. The tumor is usually large (mean diameter 10 cm.), soft, and gray and tan with necrotic and hemorrhagic areas. Histologically, it consists of a typical renal cell carcinoma intimately associated with a sarcomatous component that is characterized predominantly by a spindle cell pattern, which often resembles malignant fibrous histiocytoma or fibrosarcoma. 2·3 Of the sarcomatoid renal cell carcinomas 80% invade the renal pelvis. 1 These tumors usually present late and behave aggressively. Local invasion and distant metastasis are common. The disease has a poor prognosis with a median survival of approximately 6 months 2 · 3 and few patients survive more than a year. Pathological stage, degree of tumor necrosis and the proportion of sarcomatous components appear to be important prognostic factors. 3 Osteosarcomatous differentiation in renal cell carcinoma is rare even in the context of sarcomatoid renal cell carcinoma. In 3 series osteoid differentiation was found in only 5 of 92 cases of sarcomatoid carcinoma. 1-3 Apart from these 5 cases 10 cases (including our own) have been reported in the literature6-12 (see table). These patients present similarly to those with other renal tumors with loin or abdominal pain, hematuria, constitutional disturbances and a palpable mass. However, the extremely poor outlook in most cases is probably related to the aggressive nature of the tumor and its advanced stage at presentation. Radiography may provide a clue to the presence of osteosarcomatous elements. 11 Many reported cases showed calcifications within the tumor and 1 had a typical sunburst appearance. 10 The tumor in our case was present in a small nonfunctioning kidney and had a complex calcified structure, which led us to believe that it was a staghorn calculus. Renal tumors may coexist with staghorn calculi; which may present diagnostic difficulty. In all cases a calculus was evident when the kidney was removed. In our case the tumor that invaded and filled the renal pelvis was mainly osteosarcomatous in differentiation and, therefore, mimicked a staghorn calculus. Recently, primary osteosarcoma of the kidney was reported to present in a similar way. 13 The nosology of primary osteosarcoma of the kidney 14·15 should be considered when discussing osteosarcomatous differentiation in renal cell carcinoma. The diagnosis of primary
FIG. 3. A, poorly differentiated adenocarcinoma consistent with renal cell carcinoma. H & E, reduced from X250. B, sarcomatous differentiation with areas of osteoid and bone matrix at periphery of tumor. H & E, reduced from Xl25.
1609
REl'.TAL CELL CARCINOMA VVITH OSTEOSARCOMATOUS DIFFERENTJ:ATION
Renal cell carcinoma with osteosarcomatous differentiation Presentation
Reference Hou and Willis:' Case 2 Case 3* Newman and Vellios, case 17 Cecil et al 8 Moon et al9 • * Macke et al, case 1 10 • t
79-F 78-F 72-M
50-F 65-F
71-M
Mucci et al:n Case 4 Case 6 Sugarman et al 12 Present case
74-M
70-F
Side
Outcome
Pain, mass Pain, hematuria Pain, wt. loss, malaise, varicocele Pain, mass Pain, mass Hematuria, pain, fatigue, anorexia, wt. loss, mass
Lt. Rt. Lt. Lt. Rt. Rt.
Died 2 mos. Not known Died 10 mos. Died 2 mos. Alive 3 yrs. Died 22 mos.
Hematuria Hematuria
Unknown Unknown Lt. Lt.
Died Died Died Died
47-F
Hematuria, pain, mass
69-F
Pain, hematuria, lethargy, an·
2 mos. 3 mos. 5 mos. 2 mos.
orexia, wt. loss
* These cases should be included although the original authors had a different interpretation.
t This case was also published by Ferris, E. J., Harmon, B. H., Tonkin, I. L., Becker, G. J., Edeiken, B. S., Pfister, R. G. and Osborn, A. G.: Image interpretation session. Case 4. Radiographies, 9: 85, 1989.
renal osteosarcoma requires the absence of epithelial elements in the tumor after extensive sampling,6 and the use of electron microscopy 10 and immunocytochemical methods.'3, 14 ' 15 Some re· ported cases of primary renal osteosarcomas were not sampled sufficiently to exclude a small focus of renal cell carcinoma and even fewer had electron microscopy and immunocytochemical evaluations performed. Even if these studies were done some putative renal osteosarcoma may have originated as sarcomatoid renal cell carcinoma before the sarcomatous element overran and destroyed the epithelial component. Possible explanations for the presence of sarcomatous foci in renal cell carcinoma are metaplastic differentiation within the carcinoma, initial malignant transformation of a single primi· tive stem cell with the potential to differentiate along epithelial and mesenchymal pathways, simultaneous occurrence of separate but related carcinoma and sarcoma, and later development of sarcoma from the stroma of preexisting carcinoma. The pathogenesis of this disease is still unknown but the first of these explanations, which was advocated by Farrow et al, 1 currently seems to be the most acceptable. It is supported by the presence of epithelial characteristics evident in the sarcomatous areas on electron microscopy.rn Immunocytochemical studies could conceivably shed light on this problem but were uninformative in our case. In conclusion, osteosarcomatous differentiation of malignant tumor in the kidney is extremely rare and associated with a dismal prognosis. Exceptionally, it may present in a manner that mimics a staghorn calculus, which leads to confusion in diagnosis.
REFERENCES
l. Farrow, G. M., Harrison, E. G., Jr. and Utz, D. C.: Sarcomas and sarcomatoid and mixed malignant tumors of the kidney in adults-part III. Cancer, 22: 556, 1968.
2. Tomera, K. M., Farrow, G. M. and Lieber, M. M.: Sarcomatoid renal carcinoma. J. Urol., 130: 657, 1983. 3. Ro, J. Y., Ayala, A. G., Sella, A., Samuels, M. L. and Swanson, D. A.: Sarcomatoid renal cell carcinoma: clinicopathologic. A study of 42 cases. Cancer, 59: 516, 1987. 4. Oesterling, J.E., Kerr, L.A. and Segura, J. W.: Branched, struvite calculus and clear cell carcinoma in same kidney. Rare condition with significant implications for management. Urology, 36: 273, 1990. 5. Cowley, J. P., Connolly, C. E., Hehir, M. and O'Beirn, S. F.: Renal carcinoma with staghorn calculus, perinephric abscess, and xanthogranulomatous pyelonephritis in same kidney. Subcutaneous abscess of thigh as initial presentation. Urology, 21: 635, 1983. 6. Hou, L. T. and Willis, R. A.: Renal carcino-sarcoma, true and false. J. Path. Bacteriol., 85: 139, 1963. 7. Newman, D. and Vellios, F.: Adult carcinosarcoma (adult Wilms' tumor) of the kidney. Amer. J. Clin. Path., 42: 45, 1964. 8. Cecil, B., Woodard, B., Mickey, D. D. and Pizzo, S.: Renal carcinosarcoma. Ultrastructure and transplantation into athymic mice. Arch. Path. Lab. Med., 104: 276, 1980. 9. Moon, T. D., Dexter, D. F. and Morales, A.: Synchronous inde· pendent primary osteosarcoma and adenocarcinoma of kidney. Urology, 21: 608, 1983. 10. Macke, R. A., Hussain, M. B., Imray, T. J., Wilson, R. B. and Cohen, S. M.: Osteogenic and sarcomatoid differentiation of a renal cell carcinoma. Cancer, 56: 2452, 1985. 11. Mucci, B., Lewi, H. J. and Fleming, S.: The radiology of sarcomas and sarcomatoid carcinomas of the kidney. Clin. Rad., 38: 249, 1987. 12. Sugarman, I., Birch, P. and Carter, M.: Osteogenic differentiation in a sarcomatoid renal carcinoma. Brit. J. Urol., 66: 663, 1990. 13. Ah-Chong, A. K. and Yip, A. W. C.: Primary osteogenic sarcoma of the kidney presenting as staghorn calculus. Brit. J. Urol., 71: 233, 1993. 14. Eble, J. N., Young, R.H., Stiirkel, C. S. and Thoenes, W.: Primary osteosarcoma of the kidney: a report of three cases. J. Urogen. Path., l: 83, 1991. 15. O'Malley, F. P., Grignon, D. J., Shepherd, R. Rand Harker, L.A.: Primary osteosarcoma of the kidney. Report of a case studied by immunohistochemistry, electron microscopy, and DNA flow cytometry. Arch. Path. Lab. Med., 115: 1262, 1991.