leiomyoma is a benign tumor , which is made up of smooth muscle cells and located mostly in uterus , small bowel , and esophagus . herein , a prostatic leiomyoma that was pathologically reported after a robot - assisted radical prostatectomy ( rarp ) procedure is presented . a 70-year - old male patient with a serum prostate specific antigen value of 9.8  ng / ml underwent a transrectal ultrasound ( trus ) guided prostate biopsy . pathology revealed prostatic adenocarcinoma with 3  +  3 gleason score in 1 core on the left side . the patient had a history of irritable bowel syndrome and had bilateral inguinal herniorrhaphy operation performed 8 years ago . a transperitoneal rarp procedure with bilateral pelvic lymph node dissection was performed ( by dr . briefly , an incision was made on the anterior peritoneal covering of the douglas ' pouch , 1  cm proximal to its reflection on the rectum . seminal vesicles ( svs ) and vasa deferentia were dissected . at this stage , a 3    3  cm sized posterior mass lesion protruding from the prostate between svs was identified and dissected ( fig . figure 2 shows the removed specimen with a mass lesion protruding from the prostate located between svs . postoperative follow - up was uneventful , abdominal drain was removed at the postoperative second day , and patient was discharged on the third day . transurethral catheter was removed on postoperative day-10 followed by obtaining a cystography that demonstrated no leakage . pathology was reported as prostate adenocarcinoma , gleason score 3  +  3 , tumor size of 5    4    3  mm , left apex , and single focus with clear surgical margins . posteriorly located mass pathology was reported as a leiomyoma with a size of 3.5    3    2.8  cm . prostate had a weight of 210  g. microscopy of this mass lesion revealed a fascicular pattern of smooth muscle bundles separated by well - vascularized connective tissue ( fig . smooth muscle cells were elongated with eosinophilic or occasional fibrillar cytoplasm and distinct cell membranes . one to 2 mitotic figures per 10 high power fields in most mitotically active area were observed , and there was no significant atypia ( fig . also a single focus of prostate adenocarcinoma with gleason score 3  +  3 , size of 5    4    3  mm , located on left apex , with clear surgical margins was reported . a mass lesion , made up of smooth muscle bundles , is well demarcated from prostate tissue on the left ( h&e    4 ) . smooth muscle cells with bland cytology form fascicules ( h&e    40 ) . immunohistochemically smooth muscle actin is positive ( inset    40 ) . at postoperative ninth - month follow - up , patient is fully urinary continent with no safety pad usage . he is able to have penile erection for sexual intercourse with use of phosphodiesterase type 5 inhibitors . although pure prostatic leiomyoma is rarely seen , it was reported initially in 1876 in the autopsy material by lebel et al . in 1951 , kaufman and berneike defined prostatic leiomyomas . in 2016 , kristensen et al . stated that prostatic leiomyomas were reported in < 100 cases since it was defined . in addition , the origin of prostatic leiomyoma may reveal as wastes of mllerian duct . however , a certain mechanism of formation of prostatic leiomyoma is still not clearly presented . robotic surgery for the surgical management of a leiomyoma was previously performed by aoun et al . however , in our case the whole prostate with the posteriorly located leiomyoma was removed with the rarp procedure . the console surgeon in our case was challenged with the identification of a large mass lesion located between the svs as this area has already a limited space . therefore , it was surgically not difficult to dissect and isolate this mass lesion . however , the presence of this mass lesion made it challenging to open the denonvilliers ' fascia due to its close proximity with rectum . at this stage , intra - abdominal pressure was elevated as much as 18  mmhg temporarily to better see the area and a 4 close up magnification was used with the da vinci xi surgical robot . fourth arm of the robot holding a prograsp forceps was effectively used to lift up the prostate by holding from the svs in an attempt to make the console surgeon to see the area below the mass lesion . it is important to keep in mind that this maneuver might lead to tearing off the svs if too much force is applied as there is no tactile sensation in robotic surgery . a further trick that might also be applied could be using a 30 up lens to better see the area below the mass lesion . leiomyoma is a benign tumor and has excellent prognosis when complete resection is applied and atypia is not detected . on our case , vandoros et al . stated that negative surgical margins and absence of metastatic disease at presentation were the only factors predictive of long - term survival . therefore , prostatic leiomyosarcomas should also be kept in mind in the differential diagnosis . in conclusion , prostatic leiomyomas that are benign mesenchymal smooth muscle tumors might present as a posteriorly located mass lesion between svs that could challenge the surgeon during surgery , which should be kept in mind .
abstractbackground : prostatic leiomyoma is a benign and rare condition of the prostate . 
 robotic surgery is increasingly being applied in the surgical management of prostate cancer.case presentation : herein , a mass lesion that was located in the posterior part of the prostate between seminal vesicles that was identified during robotic surgery is presented . 
 this lesion further challenged the console surgeon during performing a robotic radical prostatectomy procedure for a 200  g large prostate with prostate cancer.conclusion : prostatic leiomyomas that are benign mesenchymal smooth muscle tumors might present as a posteriorly located mass lesion between seminal vesicles that could challenge the surgeon during surgery , which should be kept in mind .