Cystitis cystica- transrectal Ultrasound video

I uploaded this excellent demonstration of a small 5 mm. cyst in the submucosal region of the urinary bladder on youtube. I was intrigued by the appearance of this small bubble close to the upper surface of the prostate and was confused if this was a prostatic lesion or a bladder pathology. Much research on the net confirmed that this was indeed cystitis cystica. See: Ultrasound images and case study of cystitis cystica
Some studies suggest that cystitis cystica or cystitis of the bladder with cyst formation, may not be as rare as one thinks. But I disagree, this being the first case I have come across after many years of urinary bladder and TRUS/ transrectal ultrasound imaging.