Sarcomatoid carcinoma after radiation treatment of prostatic adenocarcinoma.

We report 2 patients with conventional prostatic adenocarcinoma who developed sarcomatoid carcinoma of probable prostatic origin 6 and 2.5 years after radiation treatment (seed implantation and external beam). Our cases had histologic features consistent with those cases previously reported in the literature. The tumors consisted of spindle cells with large hyperchromatic nuclei and a pattern mimicking a sarcoma. Immunohistochemical studies showed the tumors to be weakly positive for EMA, CK7, and vimentin. Ki67 staining showed positivity in more than 50% of tumor cells. The tumors also stained diffusely positive for p53 and p63. PSA and PAP were negative. Clinically, the sarcomatoid carcinomas appeared to be of prostatic origin. The pathogenesis of the tumors is still uncertain but most likely represent a radiation-induced dedifferentiation of prostatic adenocarcinoma.

The nested variant of urothelial carcinoma: clinicopathology of 2 cases.

The nested variant of urothelial carcinoma is a recently described bladder tumor entity with a rare incidence. Two cases of this disease are presented in this report; the patients in both cases were elderly men, with a predominant involvement of the trigone region. Histologically, the tumor cells were arranged in ill-defined nests and had low-grade nuclear features. Both cases had a diffusely infiltrating growth pattern with widespread local disease at cystectomy. Strong immunohistochemical staining for p63 in the neoplastic cells supports the urothelial cell nature of this neoplasm. High p53 and Ki-67 indices of this tumor correlate with the aggressiveness of this subtype.