“Cobra Head” Stone
A
7-year-old female presented with a 3-month history of episodic lower abdominal pain, associated with urgency, frequency, and dysuria. Dipstick urinalysis revealed microscopic hematuria, however, urine culture was sterile. Renal ultrasound revealed a right-sided duplex collecting system with concomitant intravesical ureterocele containing a calculus measuring 11 mm (Figure 1; available at www.jpeds.com). On the control radiograph during subsequent intravenous urography, the calculus projected over the right side of the bladder (Figure 2, A). Imaging 15 minutes postintravenous contrast injection demonstrated the classical “cobra head” sign (Figure 2, B). The prevalence of pediatric ureterocele is 1 in 4000, with a marked female preponderance.1 The “cobra head” sign seen during intravenous urography is the classical radiographic appearance resulting from bulbous dilatation of the distal end of the ureter with a surrounding radiolucent halo formed by the double mucosal wall of an intravesical ureterocele, seen within the contrast material–enhanced bladder. A dilated ureterocele may impede urine flow,
with the resultant stasis potentially precipitating ureteric stone formation. A solitary stone within a ureterocele has a prevalence in adults of 4%-39% depending on geographical location.2 Urolithiasis within a ureterocele is sufficiently rare in children2-4 that some reviews have erroneously declared that this clinical entity occurs exclusively in adults.5 n
Aisling M. Stafford, MB, BCh Department of Pediatrics
Hugh Logan, MRCP, FFR, RCSI Department of Radiology
Michael J. O’Grady, MRCPI Department of Pediatrics Midland Regional Hospital Mullingar, Ireland
References available at www.jpeds.com
Figure 2. A, Control radiograph with radiopaque calculus projected over the bladder. B, “Cobra head” sign (arrows) on intravenous urography.
J Pediatr 2014;164:428. 0022-3476/$ - see front matter. Copyright ª 2014 Mosby Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpeds.2013.09.043
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Vol. 164, No. 2 February 2014
References 1. Stephens FD. Aetiology of ureteroceles and effects of ureteroceles on the urethra. Br J Urol 1968;40:483-7. 2. Messing EM, Henry SC. Stones in orthotopic, nonobstructing ureteroceles. J Urol 1979;122:403-4. 3. Moskovitz B, Bolkier M, Levin DR. Ureterocele containing calcified stone. J Pediatr Surg 1987;22:1047-8.
4. Scuderi MG, Yankovic F, Featherstone N, Smeulders N. Voluminous “cobra-head” stone in a duplex system ureterocele: combined cystoureteroscopic and percutaneous cystolithotomy approach. J Laparoendosc Adv Surg Tech A 2013;23:484-5. 5. Cooper CS, Arlen AM. Ureterocele. Available at: http://emedicine. medscape.com/article/451105-overview. Accessed August 28, 2013.
Figure 1. Sonographic image of right-sided ureterocele containing calculus (arrow).
428.e1
A
7-year-old female presented with a 3-month history of episodic lower abdominal pain, associated with urgency, frequency, and dysuria. Dipstick urinalysis revealed microscopic hematuria, however, urine culture was sterile. Renal ultrasound revealed a right-sided duplex collecting system with concomitant intravesical ureterocele containing a calculus measuring 11 mm (Figure 1; available at www.jpeds.com). On the control radiograph during subsequent intravenous urography, the calculus projected over the right side of the bladder (Figure 2, A). Imaging 15 minutes postintravenous contrast injection demonstrated the classical “cobra head” sign (Figure 2, B). The prevalence of pediatric ureterocele is 1 in 4000, with a marked female preponderance.1 The “cobra head” sign seen during intravenous urography is the classical radiographic appearance resulting from bulbous dilatation of the distal end of the ureter with a surrounding radiolucent halo formed by the double mucosal wall of an intravesical ureterocele, seen within the contrast material–enhanced bladder. A dilated ureterocele may impede urine flow,
with the resultant stasis potentially precipitating ureteric stone formation. A solitary stone within a ureterocele has a prevalence in adults of 4%-39% depending on geographical location.2 Urolithiasis within a ureterocele is sufficiently rare in children2-4 that some reviews have erroneously declared that this clinical entity occurs exclusively in adults.5 n
Aisling M. Stafford, MB, BCh Department of Pediatrics
Hugh Logan, MRCP, FFR, RCSI Department of Radiology
Michael J. O’Grady, MRCPI Department of Pediatrics Midland Regional Hospital Mullingar, Ireland
References available at www.jpeds.com
Figure 2. A, Control radiograph with radiopaque calculus projected over the bladder. B, “Cobra head” sign (arrows) on intravenous urography.
J Pediatr 2014;164:428. 0022-3476/$ - see front matter. Copyright ª 2014 Mosby Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpeds.2013.09.043
428
Vol. 164, No. 2 February 2014
References 1. Stephens FD. Aetiology of ureteroceles and effects of ureteroceles on the urethra. Br J Urol 1968;40:483-7. 2. Messing EM, Henry SC. Stones in orthotopic, nonobstructing ureteroceles. J Urol 1979;122:403-4. 3. Moskovitz B, Bolkier M, Levin DR. Ureterocele containing calcified stone. J Pediatr Surg 1987;22:1047-8.
4. Scuderi MG, Yankovic F, Featherstone N, Smeulders N. Voluminous “cobra-head” stone in a duplex system ureterocele: combined cystoureteroscopic and percutaneous cystolithotomy approach. J Laparoendosc Adv Surg Tech A 2013;23:484-5. 5. Cooper CS, Arlen AM. Ureterocele. Available at: http://emedicine. medscape.com/article/451105-overview. Accessed August 28, 2013.
Figure 1. Sonographic image of right-sided ureterocele containing calculus (arrow).
428.e1
