[en] PURPOSE: We define guidelines for the exploration and treatment of adult mullerian duct cysts. MATERIALS AND METHODS: From January 1988 through September 1999 a diagnosis of enlarged prostatic utricle was made in 65 adults based on transrectal ultrasound findings. Echographic criteria to define simple versus complicated cysts were detailed. We reviewed the clinical presentation, diagnostic modalities, indications for invasive procedures and postoperative outcome. RESULTS: The usual clinical presentations were hematospermia in 40% of cases, other ejaculatory disturbances in 20%, recurrent testicular or pelviperineal pain in 33%, lower urinary tract irritation symptoms in 25%, lower urinary tract infection in 18.5%, male infertility in 12% and incidental finding in 18.5%. Cyst dimensions did not influence the indication for invasive procedures, which were performed in only 27 of the 65 patients (41.5%) to treat disabling symptoms in 28% and obstructive infertility in 5%, and investigate complicated cysts on transrectal ultrasound in 6%. These procedures included transperineal or transrectal puncture in 9 patients, simple endoscopic section of the utricle meatus in 12 and large marsupialisation in 6. Complete and sustained cure was noted in half of the patients treated with cyst puncture only, although echographic relapse was the rule. Endoscopic procedures definitely improved or cured 82% of the patients at a mean followup of 51 months, during which neither early nor late complications were noted. CONCLUSIONS: Since almost 60% of adults diagnosed with a mullerian duct cyst did not experience any cyst related symptoms or ejaculatory-fertility impairment, we recommend that investigation and/or treatment should only be done in symptomatic or infertile patients.