1492 | Pictorial

Spinning Top Urethra on Voiding Cystourethrogram
Pankaj Gupta, Akshay Kumar Saxena, Kushaljit Singh Sodhi

Corresponding Author:

Akshay Kumar Saxena, MD
Department of Radiodiagnosis and 
Imaging, Post Graduate Institute of 
Medical Education and Research, 
Chandigarh 160012, India.

Tel: +91 172 2756381
E-mail: fatakshay@yahoo.com

Received March 2013
Accepted June 2013

Department of Radiodiagnosis 

and Imaging, Post Graduate 

Institute of Medical Education 

and Research, Chandigarh 

160012, India.

A 10-year-old‎girl‎was‎referred‎for‎a‎voiding‎cystourethrogram‎(VCUG)‎with‎a‎history‎of‎recurrent‎urinary‎tract‎infections.‎Examination‎including‎neurological‎evaluation‎was‎unremarkable.‎Ultrasonography‎of‎the‎kidneys‎and‎bladder‎was‎normal.‎Voiding‎phase‎of‎VCUG‎was‎subsequently‎performed.‎Bladder‎
capacity‎and‎outline‎were‎normal‎(Figure‎1).‎There‎was‎marked‎dilatation‎of‎posterior‎urethra‎(Figure‎2)‎with‎smooth‎tapering‎towards‎
distal‎end‎resembling‎a‎“spinning‎top”.‎No‎vesicoureteral‎reflux‎or‎post-void‎residual‎urine‎was‎noted.‎Spinning‎top‎urethra‎(STU)‎
represents‎a‎widened‎posterior‎urethra‎seen‎mainly‎in‎girls.‎For‎a‎long‎time,‎it‎was‎considered‎a‎normal‎variation,‎due‎to‎contraction‎
of‎transverse‎fibers‎of‎urethral‎sphincter‎located‎in‎the‎distal‎urethra.(1)‎Proponents‎of‎STU‎as‎a‎pathological‎entity‎have‎attributed‎it‎
variably‎to‎meatal‎stenosis,‎urethral‎ring,‎distal‎sphincter‎dyssynergia,‎bladder‎instability‎and‎congenital‎wide‎bladder‎neck‎anomaly‎
(CWBNA).(2)‎‎Former‎three‎mechanisms‎were‎refuted‎by‎studies‎showing‎high‎urine‎flow‎rates‎in‎subjects‎with‎STU.‎For‎the‎latter‎two‎
mechanisms,‎controversy‎exists‎because‎majority‎of‎cases‎with‎instability‎and‎CWBNA‎do‎not‎show‎STU.‎Thus,‎one‎should‎consider‎
STU‎a‎normal‎variant,‎sometimes‎occurring‎in‎children‎with‎instability‎or‎CWBNA.‎Differential‎diagnosis‎includes‎Lyon¹s‎(fibrous)‎
ring‎in‎girls‎and‎urethral‎valves‎in‎males.‎(3) 

PICTORIAL

REFERENCES

1. Shopfner CE, Hutch JA. The normal urethrogram. Radiol Clin North Am. 1968;6:165-89.

2. Saxton HM, Borzyskowski M, Mundy AR, Vivian GC. Spinning top urethra: not a normal variant. Radiology. 
1988;168:147-50.

3. Lyon RP, Tanagho EA. Distal urethral stenosis in little girls. J Urol. 1965;93:379-88.

Figure 1. Voiding phase of voiding cystoure-
throgram demonstrates normal ladder capac-
ity and outline.

Figure 2. Marked dilatation of posterior ure-
thra with smooth tapering towards distal end 
resembling a “spinning top”.