Distal seminal vesicle invasion by prostate adenocarcinoma does not occur in isolation of proximal seminal vesicle invasion or lymphovascular infiltration.Pathology. 2010 Jun; 42(4):330-3.P
Seminal vesicle (SV) invasion by prostatic adenocarcinoma is a poor prognostic indicator. Despite this, there are currently no guidelines regarding SV sampling in radical prostatectomy specimens. This study examines the distribution of invasive prostatic adenocarcinoma in SVs and makes recommendations regarding sampling procedures.
The SVs from 773 consecutive radical prostatectomy specimens were serially sectioned and blocked entirely, with sections grouped into the proximal, mid and distal thirds of the glands. The site of invasive prostatic carcinoma within the muscular wall of the SV and its presence in the ejaculatory duct was recorded.
SV invasion (pT3b) was present in 56 (7.2%) cases. Patients ranged in age from 52 to 73 years (mean 64 years), with a serum prostatic specific antigen ranging from 3.7 to 46 ng/mL (mean 10.6 ng/mL). Fourteen patients (25%) had a palpable nodule or induration on digital rectal examination. Ejaculatory duct involvement was present in 49 cases. Forty-seven of 49 (95.9%) cases with ejaculatory duct involvement also had SV invasion. The mean tumour volume was 5.53 cm(3) (range 1.0-12.1 cm(3)). The tumours had a Gleason score of 4 + 3 in five cases, 4 + 3 with tertiary pattern 5 in 12 cases, 8 in two cases and 5 + 4/4 + 5 in 37 cases. All but one of the SV positive cases (98.2%) had involvement of the proximal third (15 right, 17 left and 23 both) of the gland, 35 of which (63.6%) had infiltration only of the proximal SV. For the remainder, 11 also had mid third and nine had mid and distal third involvement. Lymphovascular invasion within the prostate was seen in 71.4% of cases. In one of these cases involvement of the distal right SV was present in the absence of involvement of the proximal or mid SV.
In this study, as distal SV invasion in the absence of proximal SV invasion was found in <2% of cases, we conclude that sampling of the proximal third of the SVs is sufficient to identify virtually all cases of tumour infiltration into the SVs. If lymphovascular invasion is present in the absence of proximal SV invasion, then the remaining parts of the SV must be examined. Also, in cases with involvement of the ejaculatory duct, thorough examination of the SV is warranted.