Sacral distribution of prostatic lymph nodes visualized on spiral computed tomography with three-dimensional reconstruction.

Abstract

To evaluate the involvement of sacral lymph nodes in prostatic lymphatic drainage, using contemporary radiological imaging techniques. The study included six patients (mean age 61.8 years, range 51-75) with suspected prostate cancer. First, an oil-based contrast medium was injected into the prostate under transrectal ultrasonographic and fluoroscopic guidance, after which a standard ultrasound-guided sextant biopsy was taken. Before injecting the contrast medium, and 20 min and 24 h thereafter, the patients underwent spiral computed tomography of the pelvic region with three-dimensional reconstruction. In all patients the prostate drained via the sacral lymphatic region. Compared with the iliac lymphatic drainage system, there were fewer and narrower sacral lymph nodes. Prostatic sacral lymph nodes were located at S2 to S5, with an emphasis on S3-4. Lymph nodes were detected as presacral and in the sacral foramen, suggesting a direct lymphatic connection to the bony pelvis. These results suggest that sacral prostatic lymphatics are a potential route of spread of prostate cancer cells.