Sarcomatoid carcinoma of the prostate: Progression from adenocarcinoma is associated with p53 over-expression

Background: The pathogenesis of sarcomatoid metaplasia of prostatic adenoca rcinoma is uncertain. The histologic features of sarcomatoid carcinoma aris ing in two patients with previously irradiated prostatic adenocarcinoma are reported and the relationship between prostatic adenocarcinoma non subsequ ent sarcomatoid carcinoma is investigated by immunohistochemical detection of epithelial and soft tissue tumor markers, and p53 protein. Methods and R esults: Two patients, aged 72 and 67 years, underwent localized radiotherap y for prostatic adenocarcinoma and represented with sarcomatoid carcinoma 4 1 months and 60 months late,; respectively. In both cases the tumor consist ed of anaplastic spindle cells with occasional osteoclast-like giant cells. The initial tumors showed immunohistochemical staining typical of prostati c adenocarcinoma with absence of expression of p53 protein. The subsequent sarcomatoid carcinomas were positive for vimentin and negative for epitheli al cell markers. In both cases serial biopsies showed a temporal increase i n tumor expression of p53 protein. Conclusions: The development of sarcomat oid carcinoma in prostatic adenocarcinoma is associated with progressive ac cumulation of p53 This is suggestive of increasing clonal dominance of dedi fferentiated tumor cells carrying p53 mutations.