penile epidermal cysts in children are usually congenital and are caused by abnormal embryologic closure of the median raphe ; these cysts are termed median raphe cysts [ 2 - 4 ] . penile epidermal cysts in adults commonly develop after trauma or surgery . during wound healing , when shedding of the epithelium occurs within a closed space , cysts are formed by squamous epithelium undergoing keratinization [ 5 - 7 ] . according to this theory , an augmentation penoplasty using a dermal fat graft can cause a penile epidermal cyst . here a 44-year - old male patient who was diagnosed with liver cirrhosis was referred to the urologic department because of a slowly growing penoscrotal swelling . the patient had a history of augmentation penoplasty with a dermal fat graft 20 years previously . the mass was recognized 4 years ago , but it was very small and asymptomatic at that time . as the swelling slowly increased in size , however , the patient had difficulty with sexual intercourse . it was round , firm , and nontender and the penile skin overlying the lesion was intact and mobile . a scrotal ultrasonography to rule out any scrotal disorder showed a 5 cm3 cm5 cm heterogeneous echoic extratesticular mass with an internal linear hypoechoic lesion with no communication with the spermatic cord ( fig . the capsule of the mass was preserved and enucleated from the surrounding tissues ( fig . histologic findings showed the mass to be a cyst lined by stratified squamous epithelium ( fig . penile epidermal cysts are broadly classified into congenital cysts and secondary cysts caused by trauma or surgery . congenital cysts , such as median raphe cysts , can arise from an abnormal embryological closure of the median raphe [ 2 - 4 ] . secondary cysts can occur because of occluded hair follicles , mechanical implantation involving the injection of epidermal fragments , and obstructed eccrine ducts [ 5 - 7 ] . because the patient in this case had undergone an augmentation penoplasty with a dermal fat graft , we suspect that the cyst originated from the dermal fat graft . amid controversies regarding the indications , the demand for and supply of augmentation penoplasty techniques in korea has increased for the improvement of personal satisfaction and self - confidence . these techniques include subcutaneous injection of fat , dermal fat grafts , autologous tissue engineering , and a fasciocutaneous flap . penile epidermal cysts can be diagnosed by careful examination and radiological evaluation , including ultrasonography and computed tomography [ 5 - 7 ] . magnetic resonance imaging may be useful in cases of suspected extension into the pelvis , although such cases are rare . if a urethral diverticula or urethrocutaneous fistula is suspected , retrograde urethrography or voiding cystourethrography should be carried out [ 5 - 7 ] . in addition , the differential diagnosis of an epidermal cyst includes teratoma and dermoid cyst . however , skin and its appendages are present in a dermoid cyst , and derivatives of other germ cells are present in a teratoma . in the present case , no appendages of skin or derivatives of other germ cells were found in the surgical specimen . the patient was misdiagnosed with a hydrocele at the time of referral . physical examination and scrotal ultrasonography surprisingly , the mass was not cystic on ultrasound , but was heterogeneous in character with an internal hypoechoic lesion . surgical excision of penile epidermal cysts is the treatment of choice [ 4 - 7 ] . although no cases of malignancy arising in the wall of an epidermal cyst of the penis have previously been reported , patients with epidermal cysts should be followed up after complete cyst removal . to our knowledge , there is little literature regarding penile epidermal cysts after augmentation penoplasty , and the incidence of cyst development related to augmentation penoplasty is also unknown . we believe the present study may be helpful to further our understanding of penile epidermal cysts after augmentation penoplasty .
a 44-year - old male patient who had undergone augmentation penoplasty 20 years previously presented with a slowly growing penoscrotal mass . the penile mass was excised totally and the pathologic diagnosis was an epidermal cyst . 
 epidermal cysts are benign disorders that can occur in any part of the body . however , an epidermal cyst as a late complication of augmentation penoplasty is extremely rare . 
 we report this case of a penile epidermal cyst that developed after augmentation penoplasty .