Radiology, Vol 185, 373-376, Copyright © 1992 by Radiological Society of North America
Seminal vesicles: biopsy-related hemorrhage simulating tumor invasion at endorectal MR imaging
SA Mirowitz
Department of Radiology, Jewish Hospital at Washington University Medical Center, Washington University School of Medicine, MO 63110.
The diagnosis of seminal vesicle invasion by prostatic carcinoma is based
on observation of foci of relatively decreased signal intensity on
T2-weighted magnetic resonance (MR) images. Similar findings were observed
in the absence of tumor invasion in nine patients who had recently
undergone prostatic needle biopsy. Noncorresponding foci of abnormally
increased signal intensity were also present on T1-weighted images in eight
patients. These signal intensity abnormalities were of variable location
and extent, and usually did not follow the expected pattern of spread from
the primary prostatic tumor site. Radical prostatectomy in all patients
showed the seminal vesicles to be normal. Signal intensity patterns
observed on MR images appear to represent hemorrhagic breakdown products
related to prostatic needle biopsy, which may result in direct trauma to
the seminal vesicles. Another potential mechanism is retrograde transport
of blood products from the site of prostatic biopsy to the seminal vesicles
via the ejaculatory ducts. Awareness of this phenomenon will assist in
accurate interpretation of MR images for staging of prostate cancer.
