Affiliation:
1. Department of Pathology Indiana University School of Medicine Indianapolis IN USA
2. Department of Anatomical Pathology Melbourne Pathology, Sonic Healthcare Melbourne VIC Australia
3. Department of Anatomical Pathology QML Pathology Brisbane QLD Australia
4. Department of Pathology Brigham and Women's Hospital and Harvard Medical School Boston MA USA
5. Department of Surgery Monash University Melbourne VIC Australia
Abstract
BackgroundCarcinomas of the seminal vesicle are exceedingly rare, with a limited number of cases described in the literature. Reported cases span a relatively wide morphological spectrum, and their genomic features remain unexplored.DesignIn this study, we interrogated five primary epithelial neoplasms of the seminal vesicle using a targeted DNA sequencing platform (OncoPanel, 447 genes).ResultsThe tumours included one adenocarcinoma with intestinal phenotype presenting after external beam radiation (for prostatic adenocarcinoma), one carcinoma with Müllerian‐type clear cell phenotype, two mucinous tumours resembling low‐grade mucinous neoplasms of the appendix (LAMN) and one mucinous cystadenoma. The post‐radiation mucinous adenocarcinoma had genomic findings consistent with bi‐allelic inactivation of TP53, as well as multiple copy‐number changes with regional and chromosomal arm‐level copy‐number losses. The Müllerian‐type clear cell carcinoma exhibited a complex copy‐number profile with numerous regional and arm‐level copy‐number changes, as well as focal amplification events, including copy‐number gain of 8q and amplification of a region within 20q13. Both low‐grade mucinous tumours resembling LAMN harboured hot‐spot gain‐of‐function KRAS variants (p.G12V and p.G13D) as the only genomic alteration. No genomic alterations were detected inthe lesion diagnosed as mucinous cystadenoma.ConclusionOur results suggest that primary low‐grade mucinous neoplasms of the seminal vesicle may represent a distinct entity equivalent to appendiceal counterparts, driven by gain‐of‐function variants of RAS GTPases. The remaining tumours showed genomic features that closely resembled those of neoplasms with comparable phenotypes and/or biological characteristics arising in other sites, suggesting that they could be managed similarly, with special considerations related to their anatomical location.