accessory scrotum is the rarest developmental anomaly of scrotum . because it is usually associated with perineal lipomatous mass or anomalies in the anorectal and genitourinary system , early diagnosis and proper treatment are important to improve the quality of patients ' lives .
, we report a case of perineal accessory scrotum with a lipomatous hamartoma in a 46-year - old man .
it is a good opportunity to know the natural course of both accessory scrotum and lipomatous hamartoma in an adult patient .
a 46-year - old male patient was admitted to dongguk university gyeongju hospital because of a perineal mass .
the patient was born with the mass but he did n't undergo any treatment . there was no history of rapid growth or other complications .
he was a hepatitis b virus carrier and he had a 20-year history of rheumatoid arthritis .
physical examination revealed a round , pedunculated mass arising from the left lateral aspect of the anus .
the mass was soft , nontender and movable , measuring 5 cm  4 cm . there was a 3.5 cm  1.5 cm sized elongated skin - tag - like protuberance on the left lateral portion of the main mass .
the rugated skin of the protuberance was contiguous with the covering skin of the main mass .
there were no abnormalities in the anorectal and genitourinary system . under the impression of a lipoma , we completely excised the mass . on section , the main mass was a lump of ill - defined yellow adipose tissue partly divided by whitish fibrous septa .
the elongated small protuberance was composed of whitish soft tissue and had a rubbery texture ( fig .
microscopically , the main mass consisted of predominant mature adipose tissue that was neither encapsulated nor well circumscribed from surrounding tissue ( fig .
small bundles of bland smooth muscle fibers , mature neural tissue and blood vessels were scattered within the adipose tissue mass ( fig .
the main mass was diagnosed as a hamartoma with predominant adipose tissue ( lipomatous hamartoma ) .
the skin - tag - like protuberance was composed of numerous , irregularly oriented smooth muscle bundles , resembling the tunica dartos ( fig .
there are four representative developmental anomalies of the scrotum ; penoscrotal transposition , bifid scrotum , ectopic scrotum , and accessory scrotum . among them , accessory scrotum is extremely rare .
more than 40 cases have been reported in the english - language literature [ 2 - 6 ] .
accessory scrotum is a kind of ectopic scrotal tissue but never containing a testicle within it .
most of them are diagnosed in early childhood , especially in boys , and always arise in the perineum posterior to a normally developed original scrotum .
accessory scrotum may occur as an isolated anomaly but some could be associated with perineal lipoma / hamartoma or anomalies in the anorectal and genitourinary system . in a review of 23 cases of accessory scrotum , 19 cases ( 83% )
six out of 19 cases ( 32% ) had anomalies such as anorectal malformations or penoscrotal transposition .
even though there was no perineal mass , accessory scrotum was associated with genitourinary and anorectal anomalies including vacterl ( vertebral , anal , cardiac , tracheoesophageal , renal and limb anomalies ) association .
although accessory scrotum itself is a benign lesion , thorough physical examination and imaging studies to detect coexistent other anomalies is necessary .
prenatal early diagnosis can be made by an ultrasound examination , if we are aware of these rare congenital anomalies . when accessory scrotum is accompanied with a perineal lipomatous mass ,
accessory scrotum is usually attached to a lipomatous mass as a pedunculated skin tag or an incompletely separated protruding second nodule .
close anatomic relationship as well as frequent coexistence of two lesions suggest the possibility that the lipomatous mass is involved in the pathogenesis of accessory scrotum .
we support the hypothesis of sule et al .   emphasizing the role of mesenchymal tissue within the perineal mass in the formation of accessory scrotum .
embryologically , scrotal tissue is derived from the labioscrotal swellings that are lateral to the genital tubercle .
after 12 weeks of gestation , both labioscrotal swellings migrate inferomedially and fuse to form the scrotum . in our opinion , aberrantly developed fat tissue in the perineum may disrupt only minor cellular population in the inferior portion of a labioscrotal swelling .
but , continuous growth of intervening fat tissue forms a tumor - like mass and pushes the disrupted precursor scrotal cells .
however , we are not sure how some accessory scrotum is developed without perineal mass . in these cases ,
perineal lipomatous masses are interesting in pathologic aspect as well as clinical presentation . they have been diagnosed as lipoma   or hamartoma .
many authors named this lesion lipoma but detailed microscopic features and biologic nature were seldom described in the previous reports . in the present case ,
we noted some scattered mature neural tissue and smooth muscle bundles within the lipomatous mass .
hamartoma is a benign tumor - like malformation and is composed of abnormally proliferated mature cells and tissue that normally present in the affected regions .
hamartoma is usually asymptomatic but enlarged hamartoma can lead to complications such as mechanical obstruction , pressure effect , hemorrhage and fracture .
especially , clinicians and pathologists should take more interest when it is encountered in adult patients , because malignant transformation of hamartoma has been reported , albeit rarely . in the present case
, the hamartoma did n't cause any complications except discomfort . here , we present a 46-year - old man who was born with a perineal mass that consisted of accessory scrotum and lipomatous hamartoma .
this case will be helpful for evaluation of perineal mass and the possibility of accessory scrotum should be kept in mind .
the clinicopathologic features of accessory scrotum and lipomatous hamartoma in our adult patient were similar to those of children 's cases .
 accessory scrotum is a rare congenital anomaly that is often associated with perineal tumor or other developmental abnormalities . because most cases are diagnosed and treated in early childhood , little is known about the natural biologic course of this entity and associated lesions through time . 
 we present a case of accessory scrotum associated with lipomatous hamartoma in a 46-year - old man who was born with a perineal mass . 
 we evaluate the clinicopathologic features and discuss the pathogenesis with a review of the literature . 
INTRODUCTION
CASE REPORT
DISCUSSION