99mtc pertechnetate scintigraphy is routinely used to detect testicular torsion and differentiate this condition from acute epididymo - orchitis .
however , differentiation of torsion from hydrocele and testicular or scrotal abscess may be difficult . in this report ,
we present a 5-year old child in whom epididymitis with hydrocele was misdiagnosed as testicular torsion on scrotal scintigraphy .
a 5-year - old boy presented to the pediatric emergency department with a complaint of left scrotal swelling and local tenderness for 7 h. doppler ultrasound ( us ) imaging showed mild hydrocele of the left scrotum with no e / o torsion of the left testis .
static images at 5 and 10 min showed a halo - like pooling of tracer in the periphery of the left hemi - scrotum with a photopenic center and normal tracer uptake in the right hemi - scrotum [ figure 1 ] .
a scintigraphic diagnosis of mid - phase testicular torsion of the left testis was made and the patient was immediately operated .
however , it was discovered intraoperatively that the patient had epididymitis with a hydrocele and not torsion of the left testis .
static images at 5 and 10 min show a halo - like pooling of tracer in the periphery of the left hemi - scrotum ( arrow ) with a photopenic centre .
normal tracer uptake is seen in the right hemi - scrotum differentiation by scintigraphy between acute torsion , hydrocele , testicular or scrotal abscess , or even inguinal hernia can be difficult , and images must be interpreted in conjunction with clinical findings from scrotal transillumination .
in this situation , sonography can provide useful complementary information.[14 ] in a previous study comparing scintigraphy and us in children with scrotal pain , doppler us was able to provide the diagnosis of epididymo - orchitis in cases of false - positive scintigraphy . a peri - testicular hyperemic rim on radionuclide scrotal scintigraphy
epididymitis and hydrocele have also been reported to mimic testicular torsion on scintigraphy in adults.[68 ] the present study describes a halo - like appearance on scrotal scintigraphy caused by epididymitis with co - existing hydrocele in a clinical setting , suggestive of testicular torsion in a child .
 scintigraphic differentiation between acute torsion , hydrocele and testicular or scrotal abscess can be difficult . 
 doppler sonography may provide useful complimentary information toward diagnosis . 
 the authors describe a 5-year - old child where epididymitis with hydrocele was misdiagnosed as testicular torsion on scrotal scintigraphy . 
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