angiomyxomas are benign , locally infiltrative mesenchymal neoplasms with a predilection for the female pelvis and perineum in their reproductive age group .
these tumours often reach too large dimensions before becoming clinically symptomatic and they usually tend to recur after excision . accurate preoperative diagnosis should alert the surgeon to the need for wide excision , which is essential for prevention of local recurrence .
this is easily done with robotic assistance due to its advantages like three dimentional vision and advanced degree of freedom within the pelvic cavity .
we report here a similar case presenting as a retrovesical tumor in a male patient , which was excised with robotic assistance .
a 62-years - old male presented to us with mild obstructive lower urinary tract symptoms ( luts ) since last 1 year , with a history of acute retention of urine 3 month back with failed catheter free trial .
he underwent holmium laser enucleation of prostate ( holep ) elsewhere with histopathology reporting as benign prostatic hyperplasia .
patient failed to void after catheter removal and on further evaluation he was found to have pelvic mass .
digital rectal examination revealed a cystic mass simulating benign prostatic hyperplasia ( grade 3 ) .
magnetic resonance imaging ( mri ) pelvis revealed a well - marginated lesion within the prostate gland resulting into significant prostatomegaly with no extra prostatic extension [ figure 1 ] .
transrectal biopsy was done , which was inconclusive with no identifiable prostatic tissue . in view of discrepancy between mri report and biopsy report we performed cystoscopy which showed a hump in the prostatic urethra extending into the trigone , with prostatic lobes not visible ( because of previous holep ) .
tumor was ~6 cm  4 cm  2.5 cm in size [ figure 2 ] .
we were not able to separate the mass from bladder due to difficulty in entering into proper plane .
hence we opened bladder deliberately and resected from within the bladder , closed cystostomy and drained bladder .
histo - pathological examination [ figure 3 ] revealed moderately cellular tumor composed of sheets of spindle to stellate shaped cells with vascular channels in between . on immunohistochemistry cells were positive for desmin , focal positivity with smooth muscle antibody ( sma ) , s100 and ki-67 .
magnetic resonance imaging showing a well - marginated lesion within the prostate gland resulting into significant prostatomegaly , with no extra prostatic extension .
also gross specimen of the tumor with gelatinous appearance and size of ~6 cm  4 cm  2.5 cm .
histopathology revealed moderately cellular tumor composed of sheets of spindle to stellate shaped cells with vascular channels in between . on immunohistochemistry cells were positive for desmin , focal positivity with smooth muscle antibody , s100 and ki-67 .
aggressive angiomyxoma was first described in 1983 by steeper and rosai , and fewer than 150 cases have been reported in the world medical literature .
the recurrence rate is high , and often extensive resections are performed with considerable morbidity . in men ,
the tumour involves analogous sites including the scrotum and inguinal area and usually appears at an older age .
there might be a relation with hormonal status that might explain a female to male ratio of slightly more than 6:1 .
these lesions are characterized as soft , non - encapsulated tumours with finger - like projections infiltrating the surrounding soft - tissues .
the tumour grows slowly and is benign as suggested by the histology and by the fact that it shows no tendency to metastasize .
the low attenuation at unenhanced computed tomography ( ct ) and high signal intensity at t2-weighted mri are consistent with a myxoid matrix , high water content within the mass , or both .
the enhancement of t1-weighted mri after administration of gadolinium is related to the vascularity of aggressive angiomyxoma .
there is no evidence of gross fat within the mass , which distinguishes this tumor from other fat - containing tumors that also occur in the pelvis of women .
surgery is usually the first line of treatment ( open , laparoscopic or robotic assisted ) , radical surgery with wide margins and long - term follow - up is advised .
hormonal suppression seems to be a plausible treatment option because these tumours occur predominantly in premenopausal women of reproductive age , may grow rapidly during pregnancy and have been shown to express immunohistochemical positivity for oestrogen and progesterone receptors .
their surgery is challenging because of the infiltration and the difficult dissection . in the past , most authors advocated wide excision along with genito - urinary and digestive tract resections if necessary .
most recently robotic assisted laparoscopic excision has been promising , as seen in our case .
male angiomyxoma , athough a rare benign tumour , should be considered in the diferential diagnosis of pelvic mass in a male patient presenting with severe obstructive luts , and robotic assisted excision should be utilised wherever available .
 angiomyxoma is a rare tumour found predominantly in pelvis of young females . 
 less than 150 cases have been reported , more than 90% in females and only few cases in males . 
 its surgical excision is a big challenge and usually leads to recurrence due to incomplete excision . 
 we report a case of retrovesical angiomyxoma in an elderly male . 
 the aim of this report is to highlight the rarity of this disease , especially in males , and robotic assisted excision as an evolving option of treatment . 