•
Ureteroceles
Diagnostic Radiology
vs. Pseudoureteroceles in Adults UrographicDiagnosis 1
John R. Thornbury, M.D., Terry M. Sliver, M.D., and Robert K. Vinson, M.D. Simple ureteroceles discovered In adults on excretory urography have long been regarded as congenital anomalies, usually innocuous. Pseudoureteroceles are acquired dilatations of the submucosal portion of the distal ureter that mimic simple ureteroceles. The authors compared 5 pseudoureteroceles and 13 simple ureteroceles and found that the former were distinguished by asymmetry of the dilated ureteral lumen, moderate to severe obstruction of the upper tract, and evidence of an acquired cause such as a calculus or abnormal vesical mucosal pattern. The distinction is Important, since most pseudoureteroceles were related to malignancy involving the bladder. INDEX TERM: Ureter, ureterocele, 8[25] .1454 Radiology 122:81-84, January 1977
•
• ECENTLY WE encountered 5 adults in whom cystic
Table I:
R dilatation of the intravesical portion of the ureter
Protocol for Uroradiological Studies
A. Excretory urogram 1. Amount and concentration of contrast material used 2. Evidence of a urinary calculus, and its location 3. Bladder a. Largest size of the bladder (length X width) b. Amount of residual urine after voiding c. Bladder deformities (e.g., diverticula) d. Wall thickness e. Trigone delineation 1. Symmetry 2. Length of the interureteric ridge 4. Intravesical ureter a. Size of the dilated portion (maximum width) and change during examination b. Shape of the dilated portion (bulbous, fusiform, or other) c. Distance between ureteral orifices d. Distance between the ureteral orifice and the midline e. Appearance of the opposite ureter f. Presence and width of a "halo" 5. Upper urinary tract a. Dilatation and extent b. Duplication or other anomaly c. Evidence of pyelonephritis 6. Comparison with other urograms B. Findings on other uroradiological examinations
simulated a simple ureterocele on excretory urography. In all cases, the dilatation was secondary to obstruction of the ureteral orifice, caused by invasion of the floor of the bladder by squamous-cell carcinoma of the cervix, transitional-cell carcinoma of the bladder, radiation cystitis, or a calculus confined within the intravesical portion of the ureter. We have elected to follow the lead of Datta et al. (2) and call these dilatations "pseudoureteroceles." Other authors have reported a similar finding (1-3, 5-7), citing stricture of the ureteral orifice tollowlnq transurethral resection of the prostate (4) or ureteral catheterization (7) and pheochromocytoma originating in the intravesical ureter (1) in addition to the etiologies noted above. We have reviewed our radiological material in adults who had cystoscopic evaluation following the discovery of a ureterocele-like dilatation on the excretory urogram to determine whether there might be some urographic clue that would facilitate distinction between simple ureteroceles and pseudoureteroceles.
was repeated once in 2 patients, twice in 3, and four times in 2. Voiding cystourethrography was performed in one patient. None had had retrograde pyelography of the upper tract involved by the ureterocele or pseudoureterocele. These uroradiological studies were reviewed using the protocol indicated in TABLE I.
MATERIALS AND METHODS
Of all adult patients in whom a ureterocele was diagnosed on the basis of urographic findings during 19681975,18 (15 women aged 27-68 and 3 men aged 41-61) had undergone cystoscopy a few days later. Five of them were found to have a pseudoureterocele. The patients' records were reviewed, with emphasis on age and sex; reason for admission; congenital or acquired abnormalities of the urinary tract; a history of urinary tract instrumentation or surgery, calculus disease, recurrent urinary tract infections, or hematuria; the results of urinalysis, urine culture, BUN, serum creatinine, cystometry, and/or cystoscopy; and tollow-up information (including surgery or autopsy). Eleven patients had had excretory urography; this
RESULTS
On the basis of the cystoscopic findings, we divided the patients into three categories: A. No cystoscopic evidence of ureterocele (8 patients) B. Cystoscopic diagnosis of ureterocele (5 patients) C. Cystoscopic evidence of an abnormal ureteral orifice, but not a ureterocele (5 patients).
1 From the Departments of Radiology (J.R.T.,T.M.S.)and Surgery, Section of Urology (R.K.V.), University of Michigan Medical School, Ann Arbor, Mich. Accepted for publication in August 1976. sjh
81
82
JOHN
R.
THORNBURY AND OTHERS
PSEUDOURETEROCELE
URETEROCELE Group A Cystoscopy: No Ureterocele
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Group B Cystoscopy: Ureterocele
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Group C Cystoscopy: Abnormal Ureteral Region, Not Ureterocele
RADIATION CYSTITIS
@
®
January 1977
W5~
CARCINOMA OF CERVIX
@)
~WIO
CARCINOMA OF BLADDER
Tracings of ureteral deformities from urograms.
An opaque calculus (arrow) is impacted in the intramural portion of the ureter, simulating a simple uretero-
Radiological Size and Shape of the Terminal Ureteral Dilatation Among the 13 patients in Groups A and B, there were no predominant characteristics of size or shape of the
dilated terminal portion of the ureter that distinguished those ureteroceles seen at cystoscopy (B) from those that were not (A) (Fig. 1). However, the pattern of change in the size of the ureterocele during urography was different in the two groups. In Group A, most ureteroceles were largest
Vol. 122
URETEROCELES
83
VS. PSEUDOURETEROCELES IN ADULTS
Diagnostic Radiology
Fig. 3. CASE 14. Pseudoureterocele secondary to radiation cystitis, distinguishable by its small beak-like projection (closed arrow) and asymmetric "halo" (open arrows).
on the five-minute radiograph and tended to decrease rapidly in size thereafter. In Group S, they generally remained enlarged longer. However, these tendencies were not uniform throughout each group. Turning to Group C, we found that most (3/5) of the pseudoureteroceles varied considerably from the symmetrical fusiform or bulbous shape seen in the ureteroceles; overall, they also tended to be larger. Each of the three asymmetric pseudoureteroceles remained enlarged throughout the examination. The other two had the same overall patterns of size, shape, and change in size as the ureteroceles in Groups A and S; however, they could be identified by the contained stone in one case (Fig. 2) and by the small bladder with edematous mucosa (due to radiation cystitis) plus a beak-like medial projection of the lumen and asymmetric "halo" in the other case (Fig. 3). Dilatation of the Ureter and Collecting System Of the 13 ureteroceles in Groups A and S, 4 were associated with mild dilatation of the ureter, restricted to the distal third in 3 of them. None of the 4 demonstrated dilatation of the renal collecting system or renal parenchymal atrophy. Four of the 5 pseudoureteroceles were associated with dilatation of the upper urinary tract, involving the distal third of the ureter in 1 (CASE 14), the entire ureter in 1 (CASE 17), and the entire ureter and collecting system in 2 (CASES 16 and 18) (Fig. 4). The pseudoureterocele containing a calculus (CASE 15) was not associated with dilatation or renal abnormality: a urogram taken-one year before the development of the stone showed a normal distal ureter, and a urogram taken after the stone was passed showed a return to a normal anatomical configuration.
Fig. 4. CASE 16. Pseudoureterocele secondary to invasive carcinoma of the cervix, seen as a knob-like dilatation of the terminal ureter. Severe dilatation of the left upper tract is present.
"Halo Sign II
A "halo" sign was present in 6 of the 8 cases in Group A, all 5 cases in Group S, and 4 of the 5 cases in Group C. In CASES 5 and 6, the excreted contrast material entering the bladder was greatly diluted by the large volume of previously present urine, so that the outer margin of the dilated distal ureter could not be delineated and a "halo" sign was not seen. Rectal gas also obscured detail. In CASE 16, gross bullous edema of the vesical mucosa obscured anatomical detail in the trigone region. Other Radiological Criteria The remaining criteria evaluated in our protocol provided no predominant patterns that would aid in distinguishing ureteroceles from pseudoureteroceles. We had hoped that measurements of the distance between ureteral orifices or from one ureteral orifice to the midline would show a difference among the groups as a reflection of the degree of protrusion of the dilated ureter into the bladder; however, none was found.
84
JOHN
R.
THORNBURY AND OTHERS
DISCUSSION
Stoeckel's original application of the term "ureterocele" to cystic dilatation of the distal ureter which protruded into the bladder (8) has long been accepted in radiological and urologic diagnosis. Disagreement among authorities as to whether this dilatation was congenital or acquired has never been totally resolved (10), though most favor a congenital origin: Tanagho specifically defined a ureterocele as "a congenital cystic dilatation of the submucosal segment of the intravesical ureter" (9). Whether a simple ureterocele is seen at cystoscopy or not does not correlate with its urographic size or shape. The main determining factor is whether or not the ureterocele is distended at the time the cystoscopist inspects the ureteral orifices; another factor would be whether or not the cystoscopist knew that a ureterocele-like dilatation of the distal ureter was present on the urogram. Our urologists always review the urogram prior to cystoscopy, and the radiographic findings are coded on the film jacket in case personal consultation is not sought. For years, dilatation of the intravesical ureter and a surrounding radiolucent "halo" were considered pathognomonic of a simple ureterocele (10), with the halo considered to represent the thickness of the wall of the ureterocele. Recent reports of pseudoureteroceles show the halo sign and describe its presence in 10 of 12 cases (1-3, 5, 7). In our series of 18 cases it was present in 11 of 13 ureteroceles and 4 of 5 pseudoureteroceles. Thus the presence or absence of a halo does not distinguish a pseudoureterocele from a ureterocele with any certain-
ty. Dilatation of the upper urinary tract on the involved side was much more common with pseudoureteroceles (4 of 5 cases) than ureteroceles (4 of 13 cases) in our series. Recently reported pseudoureteroceles were commonly associated with dilatation of the upper tract (10 of 12 cases). If one excludes calculi, dilatation of the upper tract with pseudoureteroceles involved the ureter and collecting system in 3 of 4 cases in our series and 3 of 6 cases in the literature. Otherwise dilatation was mild and restricted to the distal third of the involved ureter. When dilatation was present with simple ureterocele in our series, it was mild and restricted to the distal third of the ureter in most cases. Thus dilatation of the upper tract strongly favors pseu-
January 1977
doureterocele, particularly when it is more extensive than mild distal ureteral dilatation. It is of clinical importance that a pseudoureterocele not be mistakenly dismissed as a simple ureterocele on the basis of the urographic evidence. Four of our 5 pseudoureteroceles were associated with carcinoma or the effects of cancerocidal irradiation. It is also important for radiologists and clinicians to remember that the cause of the dilatation is often impaction of calculi in the dilated submucosal portion of the ureter, not in a previously existing simple ureterocele. On the basis of our experience, the urographic diagnosis of pseudoureterocele should be much more likely than ureterocele when the following criteria are present: (a) Asymmetry of the dilated intravesical ureter (b) Dilatation of the upper urinary tract of any degree greater than minimal dilatation of the distal third of the ureter (c) Radiological evidence of an acquired cause for the ureteral obstruction, such as a calculus or abnormal bladder mucosa. Department of Radiology University Hospital Ann Arbor, Mich. 48109
REFERENCES 1. Cabanas VY, Faulconer RJ, Fekete AM: Pheochromocytoma presenting as a ureterocele. J Urol 110:389-390, Oct 1973 2. Datta NS, Ito Y, Eisenman .Jl,et al: "Cobra head" deformity. Its relationship to ureterocele and' 'pseudo-ureterocele.' J Can Assoc Radiol 23:284-286, Dec 1972 3. Datta NS, Singh SM, Bapna BC: False ureterocele: lower ureteral stone simulating ureterocele. Br J Urol 43:301-304, Jun 1971 4. Davis JP: Ureteral injury by transurethraLelectroresection and coagulation. J Urol 68: 168-177, Jul 1952 5. Morse FP III, Sears B, Brown HP: Carcinoma of the bladder presenting as simple adult ureterocele. J UroI111:36-37, Jan 1974 6. Raper FP: Ureterocele in adults. Proc R Soc Mad 51:781-782, Sep 1958 7. Sherwood T, Stevenson JJ: Ureteroceles in disguise. Br J Radiol 42:899-901, Dec 1969 8. Stoeckel W: Gynakoloqische Urologie. [In] Veit J, ed: Handbuch der Gynakoloqie. Munchen, Bergmann, 3d Ed, 1938, Vol 10, Part 1, pp 356-375 9. Tanagho EA: Anatomy and management of ureteroceles. J UroI107:729-736, May 1972 10. Wershub LP, Kirwin TJ: Ureterocele, its etiology, pathogenesis and diagnosis. Am J Surg 88:317-327, Aug 1954
Ureteroceles
Diagnostic Radiology
vs. Pseudoureteroceles in Adults UrographicDiagnosis 1
John R. Thornbury, M.D., Terry M. Sliver, M.D., and Robert K. Vinson, M.D. Simple ureteroceles discovered In adults on excretory urography have long been regarded as congenital anomalies, usually innocuous. Pseudoureteroceles are acquired dilatations of the submucosal portion of the distal ureter that mimic simple ureteroceles. The authors compared 5 pseudoureteroceles and 13 simple ureteroceles and found that the former were distinguished by asymmetry of the dilated ureteral lumen, moderate to severe obstruction of the upper tract, and evidence of an acquired cause such as a calculus or abnormal vesical mucosal pattern. The distinction is Important, since most pseudoureteroceles were related to malignancy involving the bladder. INDEX TERM: Ureter, ureterocele, 8[25] .1454 Radiology 122:81-84, January 1977
•
• ECENTLY WE encountered 5 adults in whom cystic
Table I:
R dilatation of the intravesical portion of the ureter
Protocol for Uroradiological Studies
A. Excretory urogram 1. Amount and concentration of contrast material used 2. Evidence of a urinary calculus, and its location 3. Bladder a. Largest size of the bladder (length X width) b. Amount of residual urine after voiding c. Bladder deformities (e.g., diverticula) d. Wall thickness e. Trigone delineation 1. Symmetry 2. Length of the interureteric ridge 4. Intravesical ureter a. Size of the dilated portion (maximum width) and change during examination b. Shape of the dilated portion (bulbous, fusiform, or other) c. Distance between ureteral orifices d. Distance between the ureteral orifice and the midline e. Appearance of the opposite ureter f. Presence and width of a "halo" 5. Upper urinary tract a. Dilatation and extent b. Duplication or other anomaly c. Evidence of pyelonephritis 6. Comparison with other urograms B. Findings on other uroradiological examinations
simulated a simple ureterocele on excretory urography. In all cases, the dilatation was secondary to obstruction of the ureteral orifice, caused by invasion of the floor of the bladder by squamous-cell carcinoma of the cervix, transitional-cell carcinoma of the bladder, radiation cystitis, or a calculus confined within the intravesical portion of the ureter. We have elected to follow the lead of Datta et al. (2) and call these dilatations "pseudoureteroceles." Other authors have reported a similar finding (1-3, 5-7), citing stricture of the ureteral orifice tollowlnq transurethral resection of the prostate (4) or ureteral catheterization (7) and pheochromocytoma originating in the intravesical ureter (1) in addition to the etiologies noted above. We have reviewed our radiological material in adults who had cystoscopic evaluation following the discovery of a ureterocele-like dilatation on the excretory urogram to determine whether there might be some urographic clue that would facilitate distinction between simple ureteroceles and pseudoureteroceles.
was repeated once in 2 patients, twice in 3, and four times in 2. Voiding cystourethrography was performed in one patient. None had had retrograde pyelography of the upper tract involved by the ureterocele or pseudoureterocele. These uroradiological studies were reviewed using the protocol indicated in TABLE I.
MATERIALS AND METHODS
Of all adult patients in whom a ureterocele was diagnosed on the basis of urographic findings during 19681975,18 (15 women aged 27-68 and 3 men aged 41-61) had undergone cystoscopy a few days later. Five of them were found to have a pseudoureterocele. The patients' records were reviewed, with emphasis on age and sex; reason for admission; congenital or acquired abnormalities of the urinary tract; a history of urinary tract instrumentation or surgery, calculus disease, recurrent urinary tract infections, or hematuria; the results of urinalysis, urine culture, BUN, serum creatinine, cystometry, and/or cystoscopy; and tollow-up information (including surgery or autopsy). Eleven patients had had excretory urography; this
RESULTS
On the basis of the cystoscopic findings, we divided the patients into three categories: A. No cystoscopic evidence of ureterocele (8 patients) B. Cystoscopic diagnosis of ureterocele (5 patients) C. Cystoscopic evidence of an abnormal ureteral orifice, but not a ureterocele (5 patients).
1 From the Departments of Radiology (J.R.T.,T.M.S.)and Surgery, Section of Urology (R.K.V.), University of Michigan Medical School, Ann Arbor, Mich. Accepted for publication in August 1976. sjh
81
82
JOHN
R.
THORNBURY AND OTHERS
PSEUDOURETEROCELE
URETEROCELE Group A Cystoscopy: No Ureterocele
CD
® @
Group B Cystoscopy: Ureterocele
Width 6 M M ;
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Fig. 1.
Fig. 2. cele.
Width7MMI
Group C Cystoscopy: Abnormal Ureteral Region, Not Ureterocele
RADIATION CYSTITIS
@
®
January 1977
W5~
CARCINOMA OF CERVIX
@)
~WIO
CARCINOMA OF BLADDER
Tracings of ureteral deformities from urograms.
An opaque calculus (arrow) is impacted in the intramural portion of the ureter, simulating a simple uretero-
Radiological Size and Shape of the Terminal Ureteral Dilatation Among the 13 patients in Groups A and B, there were no predominant characteristics of size or shape of the
dilated terminal portion of the ureter that distinguished those ureteroceles seen at cystoscopy (B) from those that were not (A) (Fig. 1). However, the pattern of change in the size of the ureterocele during urography was different in the two groups. In Group A, most ureteroceles were largest
Vol. 122
URETEROCELES
83
VS. PSEUDOURETEROCELES IN ADULTS
Diagnostic Radiology
Fig. 3. CASE 14. Pseudoureterocele secondary to radiation cystitis, distinguishable by its small beak-like projection (closed arrow) and asymmetric "halo" (open arrows).
on the five-minute radiograph and tended to decrease rapidly in size thereafter. In Group S, they generally remained enlarged longer. However, these tendencies were not uniform throughout each group. Turning to Group C, we found that most (3/5) of the pseudoureteroceles varied considerably from the symmetrical fusiform or bulbous shape seen in the ureteroceles; overall, they also tended to be larger. Each of the three asymmetric pseudoureteroceles remained enlarged throughout the examination. The other two had the same overall patterns of size, shape, and change in size as the ureteroceles in Groups A and S; however, they could be identified by the contained stone in one case (Fig. 2) and by the small bladder with edematous mucosa (due to radiation cystitis) plus a beak-like medial projection of the lumen and asymmetric "halo" in the other case (Fig. 3). Dilatation of the Ureter and Collecting System Of the 13 ureteroceles in Groups A and S, 4 were associated with mild dilatation of the ureter, restricted to the distal third in 3 of them. None of the 4 demonstrated dilatation of the renal collecting system or renal parenchymal atrophy. Four of the 5 pseudoureteroceles were associated with dilatation of the upper urinary tract, involving the distal third of the ureter in 1 (CASE 14), the entire ureter in 1 (CASE 17), and the entire ureter and collecting system in 2 (CASES 16 and 18) (Fig. 4). The pseudoureterocele containing a calculus (CASE 15) was not associated with dilatation or renal abnormality: a urogram taken-one year before the development of the stone showed a normal distal ureter, and a urogram taken after the stone was passed showed a return to a normal anatomical configuration.
Fig. 4. CASE 16. Pseudoureterocele secondary to invasive carcinoma of the cervix, seen as a knob-like dilatation of the terminal ureter. Severe dilatation of the left upper tract is present.
"Halo Sign II
A "halo" sign was present in 6 of the 8 cases in Group A, all 5 cases in Group S, and 4 of the 5 cases in Group C. In CASES 5 and 6, the excreted contrast material entering the bladder was greatly diluted by the large volume of previously present urine, so that the outer margin of the dilated distal ureter could not be delineated and a "halo" sign was not seen. Rectal gas also obscured detail. In CASE 16, gross bullous edema of the vesical mucosa obscured anatomical detail in the trigone region. Other Radiological Criteria The remaining criteria evaluated in our protocol provided no predominant patterns that would aid in distinguishing ureteroceles from pseudoureteroceles. We had hoped that measurements of the distance between ureteral orifices or from one ureteral orifice to the midline would show a difference among the groups as a reflection of the degree of protrusion of the dilated ureter into the bladder; however, none was found.
84
JOHN
R.
THORNBURY AND OTHERS
DISCUSSION
Stoeckel's original application of the term "ureterocele" to cystic dilatation of the distal ureter which protruded into the bladder (8) has long been accepted in radiological and urologic diagnosis. Disagreement among authorities as to whether this dilatation was congenital or acquired has never been totally resolved (10), though most favor a congenital origin: Tanagho specifically defined a ureterocele as "a congenital cystic dilatation of the submucosal segment of the intravesical ureter" (9). Whether a simple ureterocele is seen at cystoscopy or not does not correlate with its urographic size or shape. The main determining factor is whether or not the ureterocele is distended at the time the cystoscopist inspects the ureteral orifices; another factor would be whether or not the cystoscopist knew that a ureterocele-like dilatation of the distal ureter was present on the urogram. Our urologists always review the urogram prior to cystoscopy, and the radiographic findings are coded on the film jacket in case personal consultation is not sought. For years, dilatation of the intravesical ureter and a surrounding radiolucent "halo" were considered pathognomonic of a simple ureterocele (10), with the halo considered to represent the thickness of the wall of the ureterocele. Recent reports of pseudoureteroceles show the halo sign and describe its presence in 10 of 12 cases (1-3, 5, 7). In our series of 18 cases it was present in 11 of 13 ureteroceles and 4 of 5 pseudoureteroceles. Thus the presence or absence of a halo does not distinguish a pseudoureterocele from a ureterocele with any certain-
ty. Dilatation of the upper urinary tract on the involved side was much more common with pseudoureteroceles (4 of 5 cases) than ureteroceles (4 of 13 cases) in our series. Recently reported pseudoureteroceles were commonly associated with dilatation of the upper tract (10 of 12 cases). If one excludes calculi, dilatation of the upper tract with pseudoureteroceles involved the ureter and collecting system in 3 of 4 cases in our series and 3 of 6 cases in the literature. Otherwise dilatation was mild and restricted to the distal third of the involved ureter. When dilatation was present with simple ureterocele in our series, it was mild and restricted to the distal third of the ureter in most cases. Thus dilatation of the upper tract strongly favors pseu-
January 1977
doureterocele, particularly when it is more extensive than mild distal ureteral dilatation. It is of clinical importance that a pseudoureterocele not be mistakenly dismissed as a simple ureterocele on the basis of the urographic evidence. Four of our 5 pseudoureteroceles were associated with carcinoma or the effects of cancerocidal irradiation. It is also important for radiologists and clinicians to remember that the cause of the dilatation is often impaction of calculi in the dilated submucosal portion of the ureter, not in a previously existing simple ureterocele. On the basis of our experience, the urographic diagnosis of pseudoureterocele should be much more likely than ureterocele when the following criteria are present: (a) Asymmetry of the dilated intravesical ureter (b) Dilatation of the upper urinary tract of any degree greater than minimal dilatation of the distal third of the ureter (c) Radiological evidence of an acquired cause for the ureteral obstruction, such as a calculus or abnormal bladder mucosa. Department of Radiology University Hospital Ann Arbor, Mich. 48109
REFERENCES 1. Cabanas VY, Faulconer RJ, Fekete AM: Pheochromocytoma presenting as a ureterocele. J Urol 110:389-390, Oct 1973 2. Datta NS, Ito Y, Eisenman .Jl,et al: "Cobra head" deformity. Its relationship to ureterocele and' 'pseudo-ureterocele.' J Can Assoc Radiol 23:284-286, Dec 1972 3. Datta NS, Singh SM, Bapna BC: False ureterocele: lower ureteral stone simulating ureterocele. Br J Urol 43:301-304, Jun 1971 4. Davis JP: Ureteral injury by transurethraLelectroresection and coagulation. J Urol 68: 168-177, Jul 1952 5. Morse FP III, Sears B, Brown HP: Carcinoma of the bladder presenting as simple adult ureterocele. J UroI111:36-37, Jan 1974 6. Raper FP: Ureterocele in adults. Proc R Soc Mad 51:781-782, Sep 1958 7. Sherwood T, Stevenson JJ: Ureteroceles in disguise. Br J Radiol 42:899-901, Dec 1969 8. Stoeckel W: Gynakoloqische Urologie. [In] Veit J, ed: Handbuch der Gynakoloqie. Munchen, Bergmann, 3d Ed, 1938, Vol 10, Part 1, pp 356-375 9. Tanagho EA: Anatomy and management of ureteroceles. J UroI107:729-736, May 1972 10. Wershub LP, Kirwin TJ: Ureterocele, its etiology, pathogenesis and diagnosis. Am J Surg 88:317-327, Aug 1954
