511 12. White RP, Samson FE Jr (1954) Determinations of inulin in plasma and urine by use of anthrone. J Lab Clin Med 43:475 -478 13. Brown D (1982) Creatinine Analyzer 2 operating manual. Beckman Instruments, Brea, California 14. Mak RHK, Dahhan JA, Azzopardi D, Bosque M, Chanter C, Haycock GB (1983) Measurement of glomerular filtration rate in children after renal transplantation. Kidney Int 23: 410 - 413 15. Hagstam KE, Nordenfelt I, Svensson TL, Svensson SE (1974) Comparison of different methods for determination of glomenflar filtration rate in renal disease. Scan J Clin Lab Invest 34:31 - 36 16. Counahan R, Chanter C, Ghazali S, Kirkwood B, Rose F, Ban'att TM (1976) Estimation of glomerular filtration rate from plasma creatinine concentration in children. Arch Dis Child 51: 875- 878 17. Schwartz GJ, Haycock GB, Edelmann CM Jr, Spitzer A (1976) A simple estimate of glomerular filtration rate in children derived from body length and plasma creatihine. Pediatrics 58: 259- 263 18. Schwartz GJ, Feld LG, Langford DJ (1984) A simple estimate of glomerular filtration rate in full-term infants during the first year of life. J Pediatr 104:849 -854
19. Schwm'tz GJ, Gauthier B (1985) A simple estimate of glomerular filtration rate in adolescent boys. J Pediatr 106:522 - 526 20. Brion LP, Fleischman AR, McCarton C, Schwartz GJ (1986) A simple estimate of glomerular filtration rate in low birth weight infants daring the first year of life: noninvasive assessment of body composition and growth. J Pediatr 109:698-707 21. Brion LP, Boeck MA, Gauthier B, Nussbaum MP, Schwartz GJ (1989) Estimation of glomerular filtration rate in anorectic adolescents. Pediatr Nephrol 3:16 - 21 22, Morris MC, Allanby CW, Toseland P, Haycock GB, Chantler C (1982) Evaluation of a height/plasma creatihine formuIa in the measurement of glomerular filtration rate. Arch Dis Child 57:611 - 615 23. Davies JG, Taylor CM, White RHR, Marshall T (1982) Clinical limitations of the estimation of glomeru/ar filtration rate from height/plasma creatinine ratio: a comparison with simultaneous Cr edetic acid slope clearance. Arch Dis Child 57:607-610 24. Chantler C, Barratt TM (1972) Estimation of glomernlar filtration rate from plasma clearance of 51-chromium edetic acid. Arch Dis Child 47:613 -617
Ask the expert* Should asymptomatic unilateral multicystic dysplastic kidneys be removed because of the future risk of neoplasia ? Key words: Muhicystic dysplastic kidneys - Neoplasia risk The occasional discovery of apparent precursor lesions of nephroblastoma, which we have termed "nephrogenic rests" (NR) [ 1], in rnulticystic dysplastic kidneys (MCDK) has spurred concern about a possibly increased risk of tumor formation in these kidneys. The prevalence of NR in MCDK has been variously reported to be between 2% and 6.7% [2, 3]. The significance of this finding depends upon the rate at which NR become nephroblastomas, since a large proportion of NR are known to undergo spontaneous sclerosis and obsolescence [1]. In a retrospective review of kidney sections from 1,035 routine perinatal and infant necropsies~ we found 9 cases with NR (0.9%) [4]. This figure doubtless underestimates the true prevalence of NR in the general infant population, but provides a foundation for estimating the risk of tumor development in NR amongst the general pediatric population. In the United States, neophroblastoma develops in 1 of every 8-10,000 children. If NR are present in approximately 1% of liveborn infants, and 1 infant in 8,000 develops a nephroblastoma, it follows that no more than 1 in 80 infants born with NR will develop nephroblastoma. (This figure is presumably higher for Nit in infants with constitutional genetic anomalies predisposing to nephroblastoma, such as hemihypertrophy. WAGR complex (Wilms' tumor, aniridia, genital anomalies, mental retardation), and Drash syndrome, where the incidence of nephroblastoma is far higher than in the general infant population). Applying the crude estimate of 1 in 80 as the risk of tumor formation in patients with Nit, what is the risk of tumor formation in MCDK? If we use a rest prevalence of 5% in MCDK for purposes of argument, the following figures emerge concerning the efficacy of prophylactic removal of MCD/s (I) removal of 20 MCDK would be required to ablate 1
* The editors invite questions for this section
with NR; (2) removal of 80 x 2 = 1,600 MCDK would prevent 1 case of nephroblastoma; (3) given an approximate current cure rate for nephroblastoma of 90%, removal of 16,000 MCDK would be required to save 1 life. I claim no expertise in medical economics, allocation of medical resources, ethics, or nephrectomy hazards, so instead of answering the question verbally, I will let the numbers speak for themselves. I would simply add, in closing, that among more than 6,000 cases of nephroblastoma in my files, I can recall only 1 that occurred in a MCDK. This suggests to me that the NR in MCDK are not especially predisposed toward nephroblastoma formation. J. B r u c e B e c k w i t h
Division of Pediatric Pathology Loma Linda University School of Medicine Loma Linda, CA 92 350, USA
References
1. Beckwith JB, Kiviat NB, Bonadio JF (1990) Nephrogenic rests, nephroblastomatosis, and the pathogenesis of Wilms' tumor. Pediatr Pathol 10:1-36 2. Noe HN, Marshall JH, Edwards OP (1989) Nodular renal blastema in the multicystic lddiaey. J Urol 142:486-488 3. Dimmick JE, Johnson HW, Coleman GU, Carter M (1989) Wilms' tumoflet, nodular renal blastema and multicystic renal dysplasia. J Urol 142:484-485 4. Bermington JL, Beckwith JB (1975) Tumors of the kidney, renal pelvis, and ureter. In: Atlas of tumor pathology. Armed Forces Institute of Pathology, series 2, fascicle 12, p 33
19. Schwm'tz GJ, Gauthier B (1985) A simple estimate of glomerular filtration rate in adolescent boys. J Pediatr 106:522 - 526 20. Brion LP, Fleischman AR, McCarton C, Schwartz GJ (1986) A simple estimate of glomerular filtration rate in low birth weight infants daring the first year of life: noninvasive assessment of body composition and growth. J Pediatr 109:698-707 21. Brion LP, Boeck MA, Gauthier B, Nussbaum MP, Schwartz GJ (1989) Estimation of glomerular filtration rate in anorectic adolescents. Pediatr Nephrol 3:16 - 21 22, Morris MC, Allanby CW, Toseland P, Haycock GB, Chantler C (1982) Evaluation of a height/plasma creatihine formuIa in the measurement of glomerular filtration rate. Arch Dis Child 57:611 - 615 23. Davies JG, Taylor CM, White RHR, Marshall T (1982) Clinical limitations of the estimation of glomeru/ar filtration rate from height/plasma creatinine ratio: a comparison with simultaneous Cr edetic acid slope clearance. Arch Dis Child 57:607-610 24. Chantler C, Barratt TM (1972) Estimation of glomernlar filtration rate from plasma clearance of 51-chromium edetic acid. Arch Dis Child 47:613 -617
Ask the expert* Should asymptomatic unilateral multicystic dysplastic kidneys be removed because of the future risk of neoplasia ? Key words: Muhicystic dysplastic kidneys - Neoplasia risk The occasional discovery of apparent precursor lesions of nephroblastoma, which we have termed "nephrogenic rests" (NR) [ 1], in rnulticystic dysplastic kidneys (MCDK) has spurred concern about a possibly increased risk of tumor formation in these kidneys. The prevalence of NR in MCDK has been variously reported to be between 2% and 6.7% [2, 3]. The significance of this finding depends upon the rate at which NR become nephroblastomas, since a large proportion of NR are known to undergo spontaneous sclerosis and obsolescence [1]. In a retrospective review of kidney sections from 1,035 routine perinatal and infant necropsies~ we found 9 cases with NR (0.9%) [4]. This figure doubtless underestimates the true prevalence of NR in the general infant population, but provides a foundation for estimating the risk of tumor development in NR amongst the general pediatric population. In the United States, neophroblastoma develops in 1 of every 8-10,000 children. If NR are present in approximately 1% of liveborn infants, and 1 infant in 8,000 develops a nephroblastoma, it follows that no more than 1 in 80 infants born with NR will develop nephroblastoma. (This figure is presumably higher for Nit in infants with constitutional genetic anomalies predisposing to nephroblastoma, such as hemihypertrophy. WAGR complex (Wilms' tumor, aniridia, genital anomalies, mental retardation), and Drash syndrome, where the incidence of nephroblastoma is far higher than in the general infant population). Applying the crude estimate of 1 in 80 as the risk of tumor formation in patients with Nit, what is the risk of tumor formation in MCDK? If we use a rest prevalence of 5% in MCDK for purposes of argument, the following figures emerge concerning the efficacy of prophylactic removal of MCD/s (I) removal of 20 MCDK would be required to ablate 1
* The editors invite questions for this section
with NR; (2) removal of 80 x 2 = 1,600 MCDK would prevent 1 case of nephroblastoma; (3) given an approximate current cure rate for nephroblastoma of 90%, removal of 16,000 MCDK would be required to save 1 life. I claim no expertise in medical economics, allocation of medical resources, ethics, or nephrectomy hazards, so instead of answering the question verbally, I will let the numbers speak for themselves. I would simply add, in closing, that among more than 6,000 cases of nephroblastoma in my files, I can recall only 1 that occurred in a MCDK. This suggests to me that the NR in MCDK are not especially predisposed toward nephroblastoma formation. J. B r u c e B e c k w i t h
Division of Pediatric Pathology Loma Linda University School of Medicine Loma Linda, CA 92 350, USA
References
1. Beckwith JB, Kiviat NB, Bonadio JF (1990) Nephrogenic rests, nephroblastomatosis, and the pathogenesis of Wilms' tumor. Pediatr Pathol 10:1-36 2. Noe HN, Marshall JH, Edwards OP (1989) Nodular renal blastema in the multicystic lddiaey. J Urol 142:486-488 3. Dimmick JE, Johnson HW, Coleman GU, Carter M (1989) Wilms' tumoflet, nodular renal blastema and multicystic renal dysplasia. J Urol 142:484-485 4. Bermington JL, Beckwith JB (1975) Tumors of the kidney, renal pelvis, and ureter. In: Atlas of tumor pathology. Armed Forces Institute of Pathology, series 2, fascicle 12, p 33
