Genitourinary Case of the Day
Richard C. Pfister1, Laura E. Kunberger1, David B. Chalpin1, Yazan Kaakaji1, Juan Carlos Mena1, Suzanne Meleg-Smith2
Case I A 38-year-old woman with several weeks of vague mild abdominal pain and pelvic dis- comfort.
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1 Department of Radiology, Division of Abdominal Imaging, Louisiana State University Medical Center, 1542 Tulane Ave., New Orleans, LA 70112. Address correspondence to L. Kunberger. 2 Department of Pathology and Laboratory Medicine, Tulane University Medical Center, New Orleans, LA 70112. AJR 1998;171:826-834 0361-803X/98/1713-826 @ American Roentgen Ray Society
Genitourinary Case of the Day
Case 2
A 66-year-old woman with bloody vaginal discharge and suspected anterior vaginal mass.
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A, Sagittal T2-weighted fast spin-echo MR image of pelvis.
B, Sagittal gadolinium-enhanced T1-weighted gradient echo MR image of pelvis.
C, Axial enhanced CT scan of pelvis.
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Fig. 4 .- 21-year-old previously healthy man with abrupt onset of oliguria. A, Unenhanced CT scan through kidneys. B, Sagittal sonogram of right kidney. Sonographic examination of left kidney (not shown) showed similar findings.
Genitourinary Case of the Day
Case I: Horseshoe Kidney with Severe Congenital Hydronephrosis (Ureteropelvic Junction Obstruction)
The horseshoe kidney is the most common type of renal fusion anomaly, occurring in 0.1- 0.2% of births. In more than 90% of cases. the lower poles of the kidneys join across the mid-
line via an isthmus that is composed of soft tissue (ranging from functioning renal paren- chyma to a thin stringlike band of fibrous tis- sue) and that lies anterior to the aorta and inferior vena cava. In rare cases, the upper renal poles fuse. presenting as an inverted horseshoe kidney with a superior isthmus. After embry-
onic fusion, the cephalad renal ascent from the fetal pelvis is arrested by the superior mesen- teric artery or the inferior mesenteric artery [1].
The typical radiographic features of horse- shoe kidney include caudal renal position, malrotation with reversed longitudinal axis of each kidney, and anterior extrarenal pelves
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with malpositioned upper ureters passing anterior to the isthmus. Angiography usually shows multiple aberrant renal blood vessels arising from the distal aorta and iliac arteries that can contribute to the commonly coexistent ureteropelvic junction (UPJ) obstruction.
The horseshoe kidney seldom causes any complications without superimposed trauma or other associated genitourinary anomalies. Coexisting urinary tract diseases may occur slightly more often in patients with this condi- tion. Upper tract duplication, UPJ obstruction, ureterocele, vesicoureteral reflux, and, most commonly, hydronephrosis may all be associ- ated with a horseshoe kidney [1, 2].
Congenital hydronephrosis occurs in 1:100- 300 of all births. The most common causes are UPJ obstruction (25-50%), abnormal posterior urethral valves (18%), ureterocele (14%), and pri- mary megaloureter (8%); severe vesicoureteral reflux and other conditions account for the re- mainder. Approximately 75% of cases of congen- ital hydronephrosis are unilateral; about 55% of cases will be detected by the age of 5 [1, 2].
Congenital UPJ obstruction is the most com- mon cause of hydronephrosis in the horseshoe
kidney. The male:female ratio is 5:1 in congeni- tal UPJ obstruction, and 70% of the cases are unilateral with the left side more often severely involved. The cause of congenital UPJ obstruc- tion or dysfunction is somewhat controversial. An intrinsic ureteral wall abnormality results primarily in a functional disorder. In 70% of those cases, either an anomalous collagen collar or an abnormal muscle arrangement at the level of the UPJ is found. Other less common under- lying causes include urothelial ureteral folds, ureteritis, and ureteral strictures related to is- chemia. Occasionally, the underlying cause is extrinsic and related to aberrant or accessory vessels or to a fibrous adventitial band from the lower pole that may angulate and obstruct the ureter. If infection supervenes, edema or second- ary fibrosis may aggravate the condition [2-4].
Yazan Kaakaji Richard C. Pfister
References
1. Grainger R. Murphey DM, Lane V. Horseshoe kidney: a review of presentation, associated con- genital anomalies, and complications in 73 pa- tients. Ir Med J 1983;76:315-317
2. Clark WR, Malek RS. Ureteropelvic junction ob- struction I: observations on the classic type in adults. J Urol 1987;138:276-279
3. Koff SA, Hayden LJ, Cirulli C. Pathophysiology of ureteropelvic junction obstruction: experimental and clinical observations. J Urol 1984;136:336-338
4. Pfister RC, Papanicolaou N, Yoder IC. Diagnostic morphologic and urodynamic antegrade pyelog- raphy. Radiol Clin North Am 1986;24:561-571
Case 2: Adenocarcinoma of the Female Urethra
MR imaging has improved the ability to vi- sualize abnormalities of the urethra and peri- urethral tissues, particularly with the advent of higher resolution imaging using local coils. Al- though generally rare, urethral cancer is twice as common in women as in men. The classic presentation initially includes hematuria or ure- thral bleeding, followed by frequency of urina- tion and dysuria [1]. A mass may be palpable in the vagina or may be visible projecting from the urethra. Late-stage presentations include urinary retention, urethrovaginal fistula, peri- urethral abscess, and pelvic pain.
In one series of 546 malignant urethral tu- mors, 74% were squamous cell carcinoma, 16% were adenocarcinoma, and 9% were
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Fig. 2 .- 66-year-old woman with bloody vaginal discharge and suspected anterior vaginal mass. A, Sagittal T2-weighted MR image shows high-signal-intensity mass with slight heterogene- ity (straight solid arrow). Epicenter of mass is within urethra, where Foley catheter is seen. Fluid-fluid level (curved arrow) is seen in expanded vagina, caused by hemorrhage from fis- tula between urethra and vagina. Abnormal high signal intensity is seen in L5 vertebra (open arrow). Multiple osseous lesions in sacrum and ilia were seen (not shown). Most of these osseous lesions were not identified on initial 9”Tc-MDP planar bone scan; follow-up scan 1 month later revealed new metastatic focus in left femur.
B, Sagittal T1-weighted MR image obtained after IV administration of gadolinium chelate shows portions of urethral mass enhancing (arrow), confirming its solid nature.
C, Axial enhanced CT scan shows fistula (arrowhead). No osseous lesions identified on MR imaging are apparent on CT scan, even when displayed with bone window settings.
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Genitourinary Case of the Day
transitional cell carcinoma [2]. Squamous cell carcinoma affects the distal urethra, and adenocarcinoma and transitional cell carci- noma are found in the proximal urethra [3]. Adenocarcinoma, in particular, has a poor prognosis; one study reported 64% patient mortality within 24 months of diagnosis [4]. This case study and others have subdivided adenocarcinoma of the urethra into the sub- types clear cell and mucinous [5, 6].
Although it was traditionally hypothesized that mucinous adenocarcinoma arose from the periurethral Skene’s glands (a homologue of the male prostate gland), histologic and immu- nohistologic staining showed that most of the tumors resemble adenocarcinoma of the en- dometrium, prostate, or colon (intestinal re- semblance in this patient), which suggests that female urethral adenocarcinoma has more than one tissue of origin [5]. Immunohistochemical staining of these tumors was positive for pros- tate-specific antigen; the corresponding ele- vated serum prostate-specific antigen levels in the patients decreased after surgical resection, which suggests that monitoring serum pros- tate-specific antigen titers may be useful in monitoring response to therapy [6]. The diag- nosis was mucinous adenocarcinoma of the urethra invading the bladder neck, with ure- throvaginal fistula and osseous metastases.
David B. Chalpin Juan Carlos Mena
References
1. McCallum RW. Urethral neoplasms. In: Pollack HM, ed. Clinical urography, vol. 2. Philadelphia: Saunders, 1990:1404-1413
2. McCrea LE. Carcinoma of the female urethra. Urol Surv 1952;2:85-149
3. Hayes WS. The urethra. In: Davidson AJ, Hart- man DS, eds. Radiology of the kidney and urinary tract. Philadelphia: Saunders, 1994:649-667
4. Meis JM, Ayala AG, Johnson DE. Adenocarci- noma of the urethra in women: a clinicopatho- logic study. Cancer 1987;60:1038-1052
5. Dodson MK, Cliby WA, Pettavel PP, Keeny GL, Podratz KC. Female urethral adenocarcinoma: evidence for more than one tissue of origin? Gy- necol Oncol 1995:59:352-357
6. Dodson MK, Cliby WA, Keeny GL, Peterson MF, Podratz KC. Skene’s gland adenocarcinoma with increased serum level of prostate-specific antigen. Gynecol Oncol 1994;55:304-307
Case 3: Adrenocortical Carcinoma
Adrenocortical carcinoma is uncommon, ac- counting for only 0.2% of all cancer deaths [1]. These tumors are usually larger than 5 cm at the time of diagnosis and often contain intratumoral hemorrhage and necrosis. Symptoms may be produced in association with metastatic disease
(bone pain or peripheral adenopathy), mass ef- fect (abdominal fullness, pain, or early satiety), or excess hormone production by the tumor in 50% of patients [1]. “Functioning” tumors are detected at an earlier stage because of the effects of excess circulating hormones, with Cushing’s syndrome being the most common presenta- tion. Other manifestations include adrenogenital syndrome (virilization or feminization) or al- dosteronism [1]. “Nonfunctioning” tumors may produce hormones that are not sufficient in quantity or differentiation to produce clinical symptoms. Patients with nonfunctioning tumors are usually older men who have larger neo- plasms at presentation. Functioning tumors are more common in women; overall, adrenocorti- cal carcinoma occurs more often in women [2].
Adrenocortical carcinomas may be seen on radiography because of their large size and mass effect. On excretory urography, displacement of the ipsilateral kidney may be seen with the up- per pole displaced laterally and the entire kidney displaced inferiorly. The characteristic appear- ance of adrenocortical carcinoma on sonogra- phy and CT is a mass of large size (9-22 cm) with areas of central necrosis, hemorrhage, and tumoral calcifications 30% of the time [3, 4]. Contrast enhancement on CT is irregular, and echo-texture on sonography is heterogeneous. The mass may be well circumscribed despite its size, and a well-defined capsulelike rim has been described [4].
Adrenocortical carcinomas spread by direct tumor invasion, by venous extension, and by he- matogenous and lymphatic routes. Approxi- mately 35% of patients have distant metastases at the time of diagnosis [5]. A clearly defined fat plane around the primary mass (Figs. 3A and 3B) indicates that no tumor invasion to adjacent organs has occurred. CT is used in the detection of lymphadenopathy (usually paraaortic and pa- racaval) and hematogenous metastases, usually to the liver, lungs, and bone. Adrenocortical car- cinomas may invade the adrenal vein with ex- tension into the inferior vena cava and heart [6]. Vena cava involvement may be detected on du- plex sonography and CT (Fig. 3C). Cephalad delineation of the extent of tumor is necessary for planning surgery because phlebotomy and tumor thrombectomy may be attempted and cardiac surgery would be needed for intratho- racic tumor. Venacavography or MR imaging may be performed to define the extent of intra- vascular extension (Figs. 3E and 3F); MR imag- ing is particularly valuable in assessing the possibility of intracardiac extension [7].
Treatment is usually surgical; chemother- apy with agents that block adrenal steroid pro- duction is used for residual or recurrent tumor
or for patients with metastatic disease [7]. Vas- cular embolization may be used instead of or before surgery to decrease the vascularity or size of the tumor. Prognosis is dismal for un- treated patients; with therapy, 10% of patients may survive for 10 years.
A mass in the adrenal gland is statistically likely to be an adenoma or a metastasis. Find- ings suggestive of primary adrenal malignancy include large size, central necrosis or hemor- rhage, irregular contrast enhancement on CT, and metastatic lesions in the liver or lungs. Ac- curate differential diagnosis of a small adrenal mass may often be accomplished using CT or MR imaging. Cysts have attenuation similar to that of water; adenomas and myelolipomas con- tain lipids and have attenuation of less than 10 H on unenhanced CT. Chemical shift MR imaging may also be used to show fat density.
Laura E. Kunberger
References
1. Lipsett M, Hertz R, Ross G. Clinical and patho- physiologic aspects of adrenocortical carcinoma. Am J Med 1963;35:374-383
2. Sullivan M, Boileau M, Hodges C. Adrenal corti- cal carcinoma. J Urol 1978;120:660-665
3. Dunnick N, Heaston D, Halvorsen R, Moore A, Ko- robkin M. CT appearance of adrenal cortical carci- noma. J Comput Assist Tomogr 1982;6:978-982
4. Hamper UM, Fishman EK, Hartman DS, Roberts JL, Sanders RC. Primary adrenocortical carcinoma: sonographic evaluation with clinical and pathologic correlation in 26 patients. AJR 1987; 148:915-919
5. Nader S, Hickey R, Sellin R, Samaan N. Adrenal cortical carcinoma: a study of 77 cases. Cancer 1983;52:707-711
6. Dunnick N, Doppman J, Geelhoed G. Intravenous ex- tension of endocrine tumors. AJR 1980;135:471-476
7. Dunnick N. Adrenal carcinoma. Radiol Clin North Am 1994;32:99-108
Case 4: Acute Oliguric Renal Failure Caused by Hyperparathyroid Hypercalcemic Nephrocalcinosis Nephropathy
Hypercalcemia has many causes, the most common of which are hyperparathyroidism, as in the present case, and neoplasms such as mul- tiple myeloma and lymphoma. Acute hypercal- cemia can disturb the function of multiple organs in the body, particularly when the serum calcium level exceeds 13 mg/dl. Acute hyper- calcemia may lead to polyuria, polydipsia, gas- trointestinal symptoms, and changes in mental state. These symptoms may also be present to a lesser degree in chronic hypercalcemia.
Elevated serum levels of calcium insult the kidney in several ways [1]. The vasoconstrictive effect of calcium decreases renal blood flow with a subsequent decrease in the filtration rate of the
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A, Longitudinal sonogram of right upper quadrant shows 18-cm echogenic mass (calipers) containing punctate calcifications (arrowhead) with associated posterior acoustic shadow- ing. Well-defined fat plane (arrows) separates mass from liver (L).
B, Longitudinal sonogram of right kidney shows inferior aspect of mass (M) with clear tissue plane interposed between it and kidney (arrows); this indicates suprarenal origin for mass. Kidney is markedly displaced medially and inferiorly.
C, Color Doppler longitudinal image of inferior vena cava (IVC) shows echogenic tumor thrombus in IVC.
D, CT scan shows heterogeneous enhancement of mass with low-density areas of necrosis. Tumor is inseparable from intrahepatic IVC, and irregular opacification of caval lumen in- dicates tumor thrombus or direct invasion by mass (arrow).
E, Venacavogram with catheter in distal IVC shows tapering of intrahepatic IVC (curved arrow) consistent with extrinsic compression and obstruction by large tumor mass and collateral filling of azygous and hemiazygous systems (straight arrows).
F, After catheter is advanced past mass, large intraluminal filling defect is seen (arrow), corresponding to intraluminal mass seen on color Doppler sonography and compatible with tumor thrombus. No direct invasion of IVC walls from tumor was identified at surgery; however, tumor thrombus extended from adrenal vein into IVC.
renal glomeruli. Hypercalcemia may induce hy- pertension, which, in turn, has a well-described deleterious effect on renal perfusion. Elevated se- rum calcium levels can damage renal tubular function: acidification of the urine as a result of enhanced proximal tubular hydrogen ion secre- tion occurs, disturbing the acid-base balance. Parathormone can promote bicarbonate excre- tion, further disturbing the acid base homeosta- sis. Chronic hypercalcemic states lead to tubular structural damage, most severely affecting the proximal convoluted tubules; a linear relationship exists between the severity of renal tubular dam- age and serum calcium concentrations [2, 3]. The
earliest histologic changes consist of calcium ac- cumulation by the mitochondria in the proximal renal tubules and in the tubular basement mem- brane [2, 3] (Fig. 4℃). Cortical glomerular cal- cium deposition, mainly involving Bowman’s capsule, rarely occurs (Fig. 4℃). Renal failure sel- dom occurs in the absence of diffuse glomerular sclerosis [3]. Untreated chronic hypercalcemia in hyperparathyroidism has been reported to cause significant reduction in the glomerular filtration rate in less than 10% of affected patients [3].
The radiographic manifestations in the kid- neys of parathormone-induced hypercalcemia and hypercalciuria have been well described,
with renal stones and nephrocalcinosis repre- senting common manifestations. Chronic hy- percalcemia leads to irreversible calcium deposition in both the cortex and medulla. However, chronic hypercalcemic conditions such as hyperparathyroidism are more com- monly manifested as medullary nephrocalcino- sis, and cortical nephrocalcinosis is more commonly caused by acute cortical necrosis. The present case is intriguing in that the diffuse nephrocalcinosis is predominantly cortical, with relative sparing of the pyramids (Fig. 4B). Shu- man et al. [4] reported a similar case in which diffuse cortical nephrocalcinosis resulted from
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chronic paraneoplastic hypercalcemia. In the last two decades, the sonographic features of nephrocalcinosis have been established as con- sisting of highly echogenic pyramids with or without posterior acoustic shadowing [5]. Sonography has been shown to be more sensi- tive than conventional radiography for the de- tection of nephrocalcinosis [5]; it is estimated that the renal cortical attenuation needs to ex- ceed 100 H before cortical nephrocalcinosis can be detected radiographically. The conventional abdominal radiographs in the present case (not shown) did not show any renal calcifications; however, CT scans of the kidneys (Fig. 4A)
showed increased renal cortical attenuation val- ues of 70 H.
The differential diagnosis of diffuse cortical nephrocalcinosis includes acute cortical necrosis, oxalosis, glomerulonephritis, and rejected renal transplants. The differential diagnosis for diffuse cortical hyperechogenicity in normal-sized kid- neys, as shown in the present case, includes corti- cal nephrocalcinosis as well as several forms of chronic intrinsic renal disease, notably AIDS nephropathy and diabetic glomerulosclerosis.
Yazan Kaakaji Suzanne Meleg-Smith Richard C. Pfister
References
1. Benabe JE, Martinez-Maldonadeo M. Hypercal- cemic nephropathy. Arch Intern Med 1978;138: 777-779
2. Ganote CE, Philipsborn DS, Chen E, Carone FA. Acute calcium nephrotoxicity: an electron micro- scopical and semiquantitative light microscopical study. Arch Pathol 1975;99:650-657
3. Heptinstall RH. Pathology of the kidney, 3rd ed. Boston: Little, Brown, 1983;1601-1607
4. Shuman WP, Mack LA, Rogers JV. Diffuse neph- rocalcinosis: hyperechoic sonographic appear- ance. AJR 1981;136:830-832
5. Glazer GM, Callen PW, Filly RA. Medullary nephrocalcinosis: sonographic evaluation. AJR 1982;138:55-57