Morphologic Pattern, Frequency, and Spatial Distribution of Lymphovascular Invasion Foci in Radical Prostatectomy Specimens

Introduction. Lymphovascular invasion (LVI) is an adverse pathological finding in radical prostatectomy (RP) specimens associated with increased risk of metastatic disease. Its variable incidence may be attributed to underreporting. We characterized the location, quantity, and morphology of LVI foci in RP specimens and assessed the relationship between LVI and cribriform and intraductal carcinoma and metastatic risk. Methods. Two pathologists reviewed retrospectively 54 RP specimens reported as positive for LVI. Ambiguous cases were confirmed by immunostaining for ERG, CD31 and D2-40. Results. In 4/54 (7.4%), LVI could not be confirmed. Main mimickers of LVI were retraction artifact and dislodged tumor cells. Based on our review, the most important criteria to distinguish LVI from its mimickers were a corrugated lining of vascular spaces, endothelial nuclei bulging into the lumen, and presence of proteinaceous material. The LVI frequency per case ranged from 1 to 109 (median 7.5). In 47/50 (94%) cases with LVI, the associated carcinoma comprised cribriform pattern and/or intraductal carcinoma. The most common morphology of LVI foci was cribriform, occurring in 43/50 specimens, representing 469/843 (56%) of LVI foci. Most LVI foci were intraprostatic and located at the carcinoma-stroma interface. Particularly the risk of bone metastases during follow-up was independently associated with higher frequency of LVI foci (P = .009). Conclusions. The detailed description of prostatic LVI, and awareness of their predominant location and morphology may help its identification and improve the diagnostic accuracy of LVI in pathology reporting. The clinical impact of LVI quantification in prostate cancer needs validation by further studies.