The overwhelming majority of prostate cancers are conventional acinar adenocarcinomas. Although architectural and cytological variants are common such as atrophic, pseudohyperplastic or foamy gland variants, unusual histological variants such as adenosquamous carcinoma, sarcomatoid carcinoma and pleomorphic giant-cell carcinoma are exceedingly rare and are known to behave aggressively.1,2 Approximately half of adenosquamous and sarcomatoid carcinomas have been reported in the setting of previous treatment for conventional prostatic adenocarcinoma, suggesting evolution from the conventional carcinoma component.3 However, our understanding of the molecular characteristics o these rare variants is currently limited.
To our knowledge, only a few studies assessing a handful of cases have examined the molecular characteristics of these rare variants.4-7 A better understanding of the molecular features of these tumour variants could shed light on the clinical and biological diversity of prostate cancer, and potentially have therapeutic significance. We studied a cohort of rare prostati carcinoma variants, including adenosquamous carcinoma, sarcomatoid carcinoma, and pleomorphic giant-cell carcinoma, for their molecular profiles, using fluorescence in-situ hybridisation (FISH) and next-generation sequencing (NGS).