testicular adrenal rest tumors ( tarts ) are benign intratesticular masses that occur in male patients with congenital adrenal hyperplasia ( cah ) , with more than 90% of cases caused by a deficiency of 21--hydroxylase .
tarts originate from aberrant adrenal cells in the testes and can impair both spermatogenesis and endocrine testicular function .
studies have indicated that tarts may be present in childhood , with an increasing prevalence after the onset of puberty .
therefore , the early detection of tarts is important to preserve testicular function , and scrotal baseline ultrasound ( bus ) screening is recommended beginning in early childhood .
although several reports of tart sonographic features have been described previously , the reports are limited by a small numbers of cases or the old age of the patients .
this situation prompted us to investigate the sonographic features of tarts during puberty , evaluating patients no older than 18 years .
from june 2009 to january 2015 , 79 male patients had been diagnosed as cah and screened for testicular evaluation in our institute , and only 15 patients had tarts in this study .
the prevalence of tarts in our patient population was 19% ( 15/79 ) , which was all bilateral , without unilateral .
written informed consent was obtained from all patients , and the study was approved by the first affiliated hospital of sun yat - sen university institutional review board .
the first machine was an high density interconnector 5000 us machine ( phillips healthcare , tokyo , japan ) equipped with a transducer with a frequency range of 7.0 to12.0  mhz .
the other was an aplio xv machine ( toshiba medical systems , tokyo , japan ) equipped with a transducer with a frequency range of 7.5 to 10.0  mhz .
all bus examinations were performed by 1 of 2 experienced radiologists who had more than 3 years of experience in diagnosing andrological diseases .
the entire testicle was scanned thoroughly using bus , and the target lesions were identified . the location , size , shape , boundary , and echogenicity of the lesion , as well as the testicular size and the presence or absence of the testicular mediastinum were recorded .
afterwards , the transducer was maintained in a stable position and shifted to the color doppler imaging mode , and the blood supply of the lesions was recorded .
from june 2009 to january 2015 , 79 male patients had been diagnosed as cah and screened for testicular evaluation in our institute , and only 15 patients had tarts in this study .
the prevalence of tarts in our patient population was 19% ( 15/79 ) , which was all bilateral , without unilateral .
written informed consent was obtained from all patients , and the study was approved by the first affiliated hospital of sun yat - sen university institutional review board .
the first machine was an high density interconnector 5000 us machine ( phillips healthcare , tokyo , japan ) equipped with a transducer with a frequency range of 7.0 to12.0  mhz .
the other was an aplio xv machine ( toshiba medical systems , tokyo , japan ) equipped with a transducer with a frequency range of 7.5 to 10.0  mhz .
all bus examinations were performed by 1 of 2 experienced radiologists who had more than 3 years of experience in diagnosing andrological diseases .
the entire testicle was scanned thoroughly using bus , and the target lesions were identified . the location , size , shape , boundary , and echogenicity of the lesion , as well as the testicular size and the presence or absence of the testicular mediastinum were recorded .
afterwards , the transducer was maintained in a stable position and shifted to the color doppler imaging mode , and the blood supply of the lesions was recorded .
fifteen male patients involved in this study were aged 4 to 17 years ( mean age , 8.8    3.8 years ) , height 104.6 to 172.5  cm ( mean height , 138.7    22.5 years ) , and weighted 15 to 57  kg ( mean weight , 36.5    14.0  kg ) .
all of the patients had been diagnosed with cah for at least 1 year ; the blood pressure and blood glucose of the cases were all at normal levels ; 33.3% ( 5/15 ) of the cases exhibited normal bone age , and nearly 66.7% ( 10/15 ) of the cases exhibited advanced bone age ; and the andrological evaluation of these cases were listed in table 1 . in addition , 80% ( 12/15 ) of the cases were confirmed by pathological examination using surgical specimens , and immunohistochemistry showed that cd56 , inhibin , and vimentin were all positive , which were the pathological characteristics of adrenal gland ( figure 1 ) .
the remaining 3 cases were clinically confirmed ( diagnostic criteria : the testicular lesions near the mediastinum were gradually diminishing with an increasing amount of hormone therapy in patients who had been diagnosed with cah ) .
the hormone levels of these 15 patients with tarts before and after operation and hormone therapy were showed in table 2 .
basic characteristics of pubescent patients with congenital adrenal hyperplasia and testicular adrenal rest tumors testicular adrenal rest tumor was growing into testis ( a ) .
and immunohistochemistry showed that cd56 ( b ) , inhibin ( c ) , and vimentin ( d ) were all positive , which was the pathological characteristics of adrenal gland .
the basic hormone levels of pubescent patients with congenital adrenal hyperplasia and testicular adrenal rest tumors before and after operation and hormone therapy all 15 cases were bilateral , and there were 30 lesions in total .
the lesions were 1.4    0.8  cm ( range : 0.23.8  cm ) in diameter on average .
in 93.3% of the patients ( 14/15 ) , the testicular mediastinum were clearly visualized , and only 1 mediastinum exhibited a fuzzy appearance .
all of the lesions had clear boundaries and were located near the testicular mediastinum or the testicular hilum ; 83.3% ( 25/30 ) of the lesions had an irregular shape , whereas 5 ( 5/30 , 16.7% ) lesions were round .
furthermore , 56.7% ( 17/30 ) of the tart lesions exhibited homogeneous hypoechogenicity ( figure 2 ) , 36.7% ( 11/30 ) of the tart lesions exhibited heterogeneous hypoechogenicity ( figure 3 ) , and 6.6% ( 2/30 ) of the tart lesions exhibited heterogeneous isoechogenicity ( figure 4a ) .
color doppler revealed that 76.7% ( 23/30 ) of the lesions had a rich blood supply and that 23.3% ( 7/30 ) of the lesions had a scarce blood supply .
testicular adrenal rest tumor in a 4-year - old patient with congenital adrenal hyperplasia ( patient 13 ) .
sonographic examination of the left testis revealed a homogeneous hypoechoic lesion ( arrow ) with a round clear boundary , 4  mm in diameter , adjacent to the mediastinum of the testis ( a , b ) .
testicular adrenal rest tumor in a 10-year - old patient with congenital adrenal hyperplasia ( patient 5 ) .
( a ) sonographic examination of the right testis revealed a clearly defined heterogeneous hypoechoic lesion ( arrow ) , 14  mm in diameter , adjacent to the mediastinum of testis .
( b ) color doppler demonstrated marked vascularization compared with the normal testicular parenchyma ( arrow ) .
testicular adrenal rest tumor in a 15-year - old patient with congenital adrenal hyperplasia ( patient 4 ) .
( a ) sonographic examination of the left testis revealed a heterogeneous isoechoic lesion with a lobulated boundary ( arrow ) , 31  mm in diameter , adjacent to the mediastinum of testis .
( b ) sonographic examination of the left testis half a year later after operation revealed no tart lesion in the heterogeneous echoic testis caused by operation ( arrow ) .
sonographic features of pubescent patients with congenital adrenal hyperplasia and testicular adrenal rest tumors the follow - up period was from 3 to 12 months , and the tart lesions were almost disappeared after operation and hormone therapy .
the testis exhibited heterogeneous echogenicity , which might be caused by operation ( figure 4b ) .
fifteen male patients involved in this study were aged 4 to 17 years ( mean age , 8.8    3.8 years ) , height 104.6 to 172.5  cm ( mean height , 138.7    22.5 years ) , and weighted 15 to 57  kg ( mean weight , 36.5    14.0  kg ) .
all of the patients had been diagnosed with cah for at least 1 year ; the blood pressure and blood glucose of the cases were all at normal levels ; 33.3% ( 5/15 ) of the cases exhibited normal bone age , and nearly 66.7% ( 10/15 ) of the cases exhibited advanced bone age ; and the andrological evaluation of these cases were listed in table 1 . in addition , 80% ( 12/15 ) of the cases were confirmed by pathological examination using surgical specimens , and immunohistochemistry showed that cd56 , inhibin , and vimentin were all positive , which were the pathological characteristics of adrenal gland ( figure 1 ) .
the remaining 3 cases were clinically confirmed ( diagnostic criteria : the testicular lesions near the mediastinum were gradually diminishing with an increasing amount of hormone therapy in patients who had been diagnosed with cah ) .
the hormone levels of these 15 patients with tarts before and after operation and hormone therapy were showed in table 2 .
basic characteristics of pubescent patients with congenital adrenal hyperplasia and testicular adrenal rest tumors testicular adrenal rest tumor was growing into testis ( a ) .
and immunohistochemistry showed that cd56 ( b ) , inhibin ( c ) , and vimentin ( d ) were all positive , which was the pathological characteristics of adrenal gland .
the basic hormone levels of pubescent patients with congenital adrenal hyperplasia and testicular adrenal rest tumors before and after operation and hormone therapy
the lesions were 1.4    0.8  cm ( range : 0.23.8  cm ) in diameter on average . in 93.3% of the patients ( 14/15 )
, the testicular mediastinum were clearly visualized , and only 1 mediastinum exhibited a fuzzy appearance .
all of the lesions had clear boundaries and were located near the testicular mediastinum or the testicular hilum ; 83.3% ( 25/30 ) of the lesions had an irregular shape , whereas 5 ( 5/30 , 16.7% ) lesions were round .
furthermore , 56.7% ( 17/30 ) of the tart lesions exhibited homogeneous hypoechogenicity ( figure 2 ) , 36.7% ( 11/30 ) of the tart lesions exhibited heterogeneous hypoechogenicity ( figure 3 ) , and 6.6% ( 2/30 ) of the tart lesions exhibited heterogeneous isoechogenicity ( figure 4a ) .
color doppler revealed that 76.7% ( 23/30 ) of the lesions had a rich blood supply and that 23.3% ( 7/30 ) of the lesions had a scarce blood supply .
testicular adrenal rest tumor in a 4-year - old patient with congenital adrenal hyperplasia ( patient 13 ) .
sonographic examination of the left testis revealed a homogeneous hypoechoic lesion ( arrow ) with a round clear boundary , 4  mm in diameter , adjacent to the mediastinum of the testis ( a , b ) .
testicular adrenal rest tumor in a 10-year - old patient with congenital adrenal hyperplasia ( patient 5 ) .
( a ) sonographic examination of the right testis revealed a clearly defined heterogeneous hypoechoic lesion ( arrow ) , 14  mm in diameter , adjacent to the mediastinum of testis .
( b ) color doppler demonstrated marked vascularization compared with the normal testicular parenchyma ( arrow ) .
testicular adrenal rest tumor in a 15-year - old patient with congenital adrenal hyperplasia ( patient 4 ) .
( a ) sonographic examination of the left testis revealed a heterogeneous isoechoic lesion with a lobulated boundary ( arrow ) , 31  mm in diameter , adjacent to the mediastinum of testis .
( b ) sonographic examination of the left testis half a year later after operation revealed no tart lesion in the heterogeneous echoic testis caused by operation ( arrow ) .
sonographic features of pubescent patients with congenital adrenal hyperplasia and testicular adrenal rest tumors the follow - up period was from 3 to 12 months , and the tart lesions were almost disappeared after operation and hormone therapy .
the testis exhibited heterogeneous echogenicity , which might be caused by operation ( figure 4b ) .
in male patients with cah , tarts are relatively common , especially in adult males , with a prevalence of nearly 94% . in recent years
, it has become evident that some of these lesions can be detected in childhood , with a prevalence ranging from 18.3% to 29% in studies performed on children .
a similar prevalence of 19% ( 15/79 ) was found in our patient population . to the best of our knowledge
, few reports have described the imaging characteristics of tarts in puberty and adolescent ; the present study is the first to evaluate the sonographic features of tarts in a large pediatric cah population from 0 to 18 years of age .
we retrospectively analyzed the imaging features of 30 tart lesions that had been pathologically or clinically confirmed within the past 5 years .
our results revealed that all 15 cases were bilateral in onset , similar to previous reports .
although the results of delfino et al indicated that 2 of 11 cases were unilateral , we believe that this result might be influenced by lesions too small to detect ; in our series , the size of the smallest lesion was 2  mm in diameter , and it is sometimes difficult to detect lesions smaller than 2  mm .
ultrasonography revealed that all 30 lesions in our series were located adjacent to the testicular mediastinum and had clear boundaries .
the location in the mediastinum has previously been described and is considered a typical feature of tarts in cah .
the results of stikkelbroeck et al revealed blurring of the margins in 36% of lesions , but all of our lesions had clearly defined margins , which may be due to the advanced ultrasonic technology compared with that used a decade ago . in our study , 83.3% ( 25/30 ) of the lesions had an irregular , lobulated shape , and ranged from 0.7 to 3.8  cm in size .
five ( 5/30 , 16.7% ) lesions were round , ranging from 0.2 to 0.6  cm in size .
we believe the tarts begin as small , distinct lesions that could grow and coalesce to form 1 large , lobulated lesion .
the histopathological hypothesis of the development of these lesions was that they originated from aberrant adrenal rest cells ; when stimulated by adrenocorticotropic hormone , these adrenal rest cells in the testicular tissue were activated and became hyperplastic , subsequently appearing as confluent lesions .
the tarts in cah in our group exhibited hypoechogenicity compared with normal testicular tissue except in 6.6% ( 2/30 ) of the lesions , which exhibited isoechogenicity .
by contrast , with respect to lesion size , stikkelbroeck et al reported that 17 of 20 lesions < 2  cm were hypoechoic , whereas all lesions > 2  cm were hypoechoic with hyperechoic reflections .
the significant difference in the echogenicity of tarts was likely due to the selection of patients , who were all adults in stikkelbroeck 's report and might have had a longer disease course compared with the pubescent patients ; furthermore , hyperechogenicity might indicate fibrotic changes or calcifications in the lesions .
color doppler revealed that 76.7% ( 23/30 ) of the lesions exhibited a rich blood supply , whereas 23.3% ( 7/30 ) of the lesions exhibited a scarce blood supply .
in addition , the vessels coursing through the lesions did not deviate or change in caliber .
the latter observation has also been made by avila et al and stikkelbroeck et al , who suggested that this appearance may be useful in distinguishing tarts because it has not been described with other testicular tumors .
therefore , tart screening by scrotal bus beginning from early childhood is important in male patients with cah to prevent the development of future complications , especially infertility .
notably , the high tart prevalence in adult patients is due to failure of detection during childhood .
our study still has a limitation , which is the uncertain relationship between tarts size and abnormal hormone levels .
so , a well designed clinical study is needed to get the relationship between them . in conclusion ,
the sonographic characteristics of tarts are bilateral growth , location adjacency to the testicular mediastinum , hypoechogenicity , and a rich blood supply .
we recommend that ultrasound be performed from the onset of puberty in all boys with classic cah to avoid the risk of infertility .
 abstractthe aim of this study was to evaluate the imaging features of testicular adrenal rest tumors ( tarts ) on baseline ultrasound ( bus).the imaging features of 30 tart lesions pathologically or clinically confirmed in 15 patients who had undergone bus were evaluated , and the sonographic characteristics of the lesions were analyzed.all 15 cases were bilateral and located near the testicular mediastinum . 
 approximately 56.7% ( 17/30 ) of the tart lesions exhibited homogeneous hypoechogenicity , 36.7% ( 11/30 ) of the lesions exhibited heterogeneous hypoechogenicity , and 6.6% ( 2/30 ) of the lesions exhibited heterogeneous isoechogenicity . 
 in addition , 76.7% ( 23/30 ) of the lesions exhibited a rich blood supply , whereas 23.3% ( 7/30 ) of the lesions exhibited a scarce blood supply.the sonographic characteristics of the tarts were bilateral growth , location adjacent to the testicular mediastinum , hypoechogenicity , and rich blood supply , which may play important roles in early clinical diagnosis . 