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Urinary Bladder Pseudolesions on Contrast-Enhanced Helical CT: Frequency and Clinical Implications
IMAGING
Materials and methods. We reviewed the US, CT and MR images of 29 cases of histopathologically confirmed nephroblastomatosis sent to our department for reference evaluation (German nephroblastorna study). The series included 17 kidneys with NR, 6 kidneys with WT and 32 kidneys with both NR and WT. Results. NR presented as multinodular, peripheral, cortical lesions, the diffuse form of distribution being less common. Foci were homogeneous and of low echogenicity, density or signal intensity. The lesions were most clearly depicted with contrast-enhanced CT and T1-weighted (Tl-W)MR images. Lesions smaller than 1 cm were rarely identified by US. The most reliable criterion to differentiate NR from WT was their homogeneity. Conclusions. Contrast-enhanced CT and T1-W MR images are of similar potential and superior to US in the diagnosis of nephroblastomatosis. Due to the significant radiation dose of serial CT, MR imaging should be the method of choice wherever it is available. The cost-effectiveness and availability of US makes it ideal for serial follow-up of known lesions.
Editorial Comment: The authors review 29 cases of histopathologicallyproved nephroblastomatosis, including 17 kidneys with nephrogenic rests, 6 with Wilms tumor, and 32 with nephrogenic rests and Wilms tumor. They report that the multinodular peripheral form of nephrogenic rests was f a r more common than the diffuse form. Nephrogenic rests were homogeneous and of low echogenicity, density or signal intensity. Contrast enhanced computerized tomography and T1-weighted magnetic resonance imaging (MRI) more clearly depicted involvement of the kidney with nephrogenic rests than ultrasound. Lesions smaller than 1 cm. were often missed on ultrasound. The authors recommend that MRI be the method of choice because of the radiation exposure concern. However, the costmenefit factor must be included in choosing between these 2 studies at any institution. Ultrasound may be suitable for followup of patients with nephroblastomatosisfirst detected on computerized tomography or MRI. The major difficulty is differentiating Wilms tumor from nephrogenic rests. The problem is compounded by the fact that biopsy differentiation also can be extremely difficult from a microscopic point of view and because small lesions may be missed on biopsy. The authors suggest that the most reliable method to differentiate nephrogenic rests from Wilms tumor is that Wilms tumor tends to be inhomogeneous. However, in practice this differentiation is often difficult to make. Stanford M. Goldman, M.D.
Urinary Bladder Pseudolesions on Contrast-EnhancedHelical C T Frequency and Clinical Implications E. W. ~ L c o M. ~ , NINO-MURCIA AND J. S. RHEE,Departments of Radiology, Veterans AffairsPalo Alto Health Care System, Palo Alto and Stanford University School of Medicine, Stanford, California AJR, 171:1349-1354, 1998 OBJECTIVE. The goals of this study were to define the distinguishing characteristics and frequency of urinary bladder pseudolesions that are produced as opacified urine enters the bladder during contrastenhanced helical CT of the abdomen and to evaluate the usefulness of delayed imaging in differentiating pseudolesions from true lesions. SUBJECTS AND METHODS. Contrast-enhanced routine CT scans of 184 patients were obtained prospectively. For each patient, we also obtained 5-min delayed images of the bladder. The images were evaluated for apparent focal thickening or polypoid lesions involving the bladder wall, findings that may represent bladder neoplasia, without knowledge of the indications for the scan, the patient’s clinical history, or the patient’s diagnosis. Apparent lesions that were visible on routine images and entirely absent on delayed images were considered to be pseudolesions. RESULTS. Apparent lesions were identified on 20 (10.9% 2 4.5% [limits of the 95%confidence interval]) of the routine CT scans. Using delayed images, the 21 apparent lesions in these 20 patients were resolved as 13 pseudolesions and eight true lesions. Pseudolesions were present in 6.5% f 3.6% of patients. CONCLUSION. Pseudolesions of the bladder that are indistinguishable from true lesions pose a significant clinical problem in routine contrast-enhanced helical CT of the abdomen. Delayed imaging of the bladder is useful in distinguishing pseudolesions from true lesions.
Editorial Comment: The authors report 8 true and 13 pseudo lesions of the bladder among 184 patients who underwent contrast enhanced routine computerized tomography. The pseudo lesions were present in 6.5 f 3.6% of patients and represented apparent wall thickening as the result of mixing opacified and nonopacified urine in the bladder. These lesions appear as wall thickening or plypoid on computerized tomography, and are subsequently pmved by v-g imaging techniques not to represent any other pathological procesa True and pseudo lesions tend to be posterior, although they can be right or left anterior, and there is considerable overlap. It is important to recognize that wall thickening should not be readily dismissed as a pseudo lesion but rather must be confirmed as a true or pseudo lesion. Ipsilated hydronephro-
1403
1404
PEDIATRIC UROLOGY
sis or hydroureter is seen only with true lesions. Because this study was done predominantly in elder men, the incidence of pseudo lesions in those younger than 40 years or in women is unknown. Early image or further delayed acquisition should allay any doubts as to the presence or absence of a true lesion. I believe that this observation is important and practical, and proper initial radiological imaging should preclude a misdiagnosis. Stanford M. Goldman, M.D.
Atypical Cystic Renal Masses
N. S. CURRY,Department of Uroradiology, Medical University of South Carolina, Charleston, South Carolina Abdom. Imag., 2 3 230-236, 1998
No Abstract
Renal Neoplasms in Patients With Renal Cystic Diseases E. A. P. REICHARD, M. A. RO~BIDOLJX AND N. R. DUNNICK, Department
of
Radiology, University of Michigan
Medical Center, Ann Arbor, Michigan Abdom. Imag., 2 3 237-248, 1998
No Abstract
The Small Renal Mass: Detection, Characterization, and Management
R. J. ZAGORIAAND R. B. DYER,Department
of
Radiology, Bowman Gray School of Medicine, Wake Forest
University, Winston-Salem, North Carolina Abdom. Imag., 2 3 256-265,1998 No Abstract
Editorial Comment: A n excellent series of review articles has recently appeared in Abdominal Imaging under the guest editorship of Dr. Reed Dunnick. I recommend this featured section, especially these articles. They will acquaint you with the latest in current thinking regarding the management of these difficult cases. Stanford M. Goldman, M.D.
PEDIATRIC UROLOGY Study of a Rindred With Classic Congenital Adrenal Hyperplasia: Diagnostic Challenge Due to Phenotypic Variance D. CHIN,P. W. SPEISER, J. IMPERATO-MCGINLEY, N. DWT, N. ULI, R. DAVIDAND S. E. OBERFIELD, Departments of Pediatrics, New York University Medical Center and North Shore University Medical Center, and Department of Medicine, Cornell University Medical Center, New York, New York J. Clin. Endocr. Metab., 83: 1940-1945, 1998 We sought to determine the concordance of the phenotype and genotype in a kindred with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The variation in phenotypic expression within this family underscores the difficulty of establishing the diagnosis in the absence of newborn screening, even with a heightened index of suspicion. Steroidogenic profiles were obtained for the three affected siblings. The available clinical history of the two affected aunts was retrieved. Genotyping was performed on several members of the kindred. Detailed sequencing of the entire CYPPl gene of two clinically dissimilar subjects in this family was undertaken to explore the possibility of other mutations or polymorphisms. PCR with ligase detection reaction analysis of CYP2l revealed that the affected family members 111-2, III-3,III-4, 11-3, and 11-4, all were compound heterozygotes carrying the intron 2 point mutation known to interfere with splicing (nucleotide 656 A to G)and the exon 4 point mutation causing a nonconservative substitution of asparagine for isoleucine at codon 172 (1172N). Detailed sequencing of the gene was
Materials and methods. We reviewed the US, CT and MR images of 29 cases of histopathologically confirmed nephroblastomatosis sent to our department for reference evaluation (German nephroblastorna study). The series included 17 kidneys with NR, 6 kidneys with WT and 32 kidneys with both NR and WT. Results. NR presented as multinodular, peripheral, cortical lesions, the diffuse form of distribution being less common. Foci were homogeneous and of low echogenicity, density or signal intensity. The lesions were most clearly depicted with contrast-enhanced CT and T1-weighted (Tl-W)MR images. Lesions smaller than 1 cm were rarely identified by US. The most reliable criterion to differentiate NR from WT was their homogeneity. Conclusions. Contrast-enhanced CT and T1-W MR images are of similar potential and superior to US in the diagnosis of nephroblastomatosis. Due to the significant radiation dose of serial CT, MR imaging should be the method of choice wherever it is available. The cost-effectiveness and availability of US makes it ideal for serial follow-up of known lesions.
Editorial Comment: The authors review 29 cases of histopathologicallyproved nephroblastomatosis, including 17 kidneys with nephrogenic rests, 6 with Wilms tumor, and 32 with nephrogenic rests and Wilms tumor. They report that the multinodular peripheral form of nephrogenic rests was f a r more common than the diffuse form. Nephrogenic rests were homogeneous and of low echogenicity, density or signal intensity. Contrast enhanced computerized tomography and T1-weighted magnetic resonance imaging (MRI) more clearly depicted involvement of the kidney with nephrogenic rests than ultrasound. Lesions smaller than 1 cm. were often missed on ultrasound. The authors recommend that MRI be the method of choice because of the radiation exposure concern. However, the costmenefit factor must be included in choosing between these 2 studies at any institution. Ultrasound may be suitable for followup of patients with nephroblastomatosisfirst detected on computerized tomography or MRI. The major difficulty is differentiating Wilms tumor from nephrogenic rests. The problem is compounded by the fact that biopsy differentiation also can be extremely difficult from a microscopic point of view and because small lesions may be missed on biopsy. The authors suggest that the most reliable method to differentiate nephrogenic rests from Wilms tumor is that Wilms tumor tends to be inhomogeneous. However, in practice this differentiation is often difficult to make. Stanford M. Goldman, M.D.
Urinary Bladder Pseudolesions on Contrast-EnhancedHelical C T Frequency and Clinical Implications E. W. ~ L c o M. ~ , NINO-MURCIA AND J. S. RHEE,Departments of Radiology, Veterans AffairsPalo Alto Health Care System, Palo Alto and Stanford University School of Medicine, Stanford, California AJR, 171:1349-1354, 1998 OBJECTIVE. The goals of this study were to define the distinguishing characteristics and frequency of urinary bladder pseudolesions that are produced as opacified urine enters the bladder during contrastenhanced helical CT of the abdomen and to evaluate the usefulness of delayed imaging in differentiating pseudolesions from true lesions. SUBJECTS AND METHODS. Contrast-enhanced routine CT scans of 184 patients were obtained prospectively. For each patient, we also obtained 5-min delayed images of the bladder. The images were evaluated for apparent focal thickening or polypoid lesions involving the bladder wall, findings that may represent bladder neoplasia, without knowledge of the indications for the scan, the patient’s clinical history, or the patient’s diagnosis. Apparent lesions that were visible on routine images and entirely absent on delayed images were considered to be pseudolesions. RESULTS. Apparent lesions were identified on 20 (10.9% 2 4.5% [limits of the 95%confidence interval]) of the routine CT scans. Using delayed images, the 21 apparent lesions in these 20 patients were resolved as 13 pseudolesions and eight true lesions. Pseudolesions were present in 6.5% f 3.6% of patients. CONCLUSION. Pseudolesions of the bladder that are indistinguishable from true lesions pose a significant clinical problem in routine contrast-enhanced helical CT of the abdomen. Delayed imaging of the bladder is useful in distinguishing pseudolesions from true lesions.
Editorial Comment: The authors report 8 true and 13 pseudo lesions of the bladder among 184 patients who underwent contrast enhanced routine computerized tomography. The pseudo lesions were present in 6.5 f 3.6% of patients and represented apparent wall thickening as the result of mixing opacified and nonopacified urine in the bladder. These lesions appear as wall thickening or plypoid on computerized tomography, and are subsequently pmved by v-g imaging techniques not to represent any other pathological procesa True and pseudo lesions tend to be posterior, although they can be right or left anterior, and there is considerable overlap. It is important to recognize that wall thickening should not be readily dismissed as a pseudo lesion but rather must be confirmed as a true or pseudo lesion. Ipsilated hydronephro-
1403
1404
PEDIATRIC UROLOGY
sis or hydroureter is seen only with true lesions. Because this study was done predominantly in elder men, the incidence of pseudo lesions in those younger than 40 years or in women is unknown. Early image or further delayed acquisition should allay any doubts as to the presence or absence of a true lesion. I believe that this observation is important and practical, and proper initial radiological imaging should preclude a misdiagnosis. Stanford M. Goldman, M.D.
Atypical Cystic Renal Masses
N. S. CURRY,Department of Uroradiology, Medical University of South Carolina, Charleston, South Carolina Abdom. Imag., 2 3 230-236, 1998
No Abstract
Renal Neoplasms in Patients With Renal Cystic Diseases E. A. P. REICHARD, M. A. RO~BIDOLJX AND N. R. DUNNICK, Department
of
Radiology, University of Michigan
Medical Center, Ann Arbor, Michigan Abdom. Imag., 2 3 237-248, 1998
No Abstract
The Small Renal Mass: Detection, Characterization, and Management
R. J. ZAGORIAAND R. B. DYER,Department
of
Radiology, Bowman Gray School of Medicine, Wake Forest
University, Winston-Salem, North Carolina Abdom. Imag., 2 3 256-265,1998 No Abstract
Editorial Comment: A n excellent series of review articles has recently appeared in Abdominal Imaging under the guest editorship of Dr. Reed Dunnick. I recommend this featured section, especially these articles. They will acquaint you with the latest in current thinking regarding the management of these difficult cases. Stanford M. Goldman, M.D.
PEDIATRIC UROLOGY Study of a Rindred With Classic Congenital Adrenal Hyperplasia: Diagnostic Challenge Due to Phenotypic Variance D. CHIN,P. W. SPEISER, J. IMPERATO-MCGINLEY, N. DWT, N. ULI, R. DAVIDAND S. E. OBERFIELD, Departments of Pediatrics, New York University Medical Center and North Shore University Medical Center, and Department of Medicine, Cornell University Medical Center, New York, New York J. Clin. Endocr. Metab., 83: 1940-1945, 1998 We sought to determine the concordance of the phenotype and genotype in a kindred with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The variation in phenotypic expression within this family underscores the difficulty of establishing the diagnosis in the absence of newborn screening, even with a heightened index of suspicion. Steroidogenic profiles were obtained for the three affected siblings. The available clinical history of the two affected aunts was retrieved. Genotyping was performed on several members of the kindred. Detailed sequencing of the entire CYPPl gene of two clinically dissimilar subjects in this family was undertaken to explore the possibility of other mutations or polymorphisms. PCR with ligase detection reaction analysis of CYP2l revealed that the affected family members 111-2, III-3,III-4, 11-3, and 11-4, all were compound heterozygotes carrying the intron 2 point mutation known to interfere with splicing (nucleotide 656 A to G)and the exon 4 point mutation causing a nonconservative substitution of asparagine for isoleucine at codon 172 (1172N). Detailed sequencing of the gene was