Welcome to Health care magic.
1.It would have been good if you have mentioned age and gender of the male, so i will try to explain both male and female pathology. ( take only what you are).
2. Tubular cystic lesion in the pelvic region and repeat scan after a week time - in females i would have suspect
fallopian tube obstruction with collection - hydro-salpinx.
3.Both in males and females - it could be dilated
ureter due to vesico-ureteric junction obstruction. Which will appears as tubular cystic structures.
4.Other possible causes could be bladder diverticula - out pouching of the bladder.
5.Another cause which could be congenital - bladder duplication.
6. Next time please mention Age, Sex - that will help to serve you better.
Hope it helps you. Wish you a good health.
Anything to ask ? do not hesitate. Thank you.