Histopathological findings after treatment of prostate cancer using high-intensity focused ultrasound (HIFU).

BACKGROUND: High-intensity focused ultrasound (HIFU) treatment is a novel minimally invasive therapeutic option for patients with localized prostate cancer. Little is known about the histological findings in prostate biopsies upon HIFU treatment. METHOD: We examined the spectrum of histological changes in prostate biopsies of 25 prostate cancer patients who were previously treated with HIFU. The biopsies were taken 180 days after HIFU treatment. RESULTS: Seventy-two percent of the cases showed necrosis, often accompanied by acute, chronic, or granulomatous inflammation. Mild or moderate fibrosis was present in all biopsies. In benign glands, histological examination revealed a heterogeneous cellular damage and cellular response including cytologic atypia and basal cell hyperplasia. Eleven patients (44%) had residual prostatic carcinoma after treatment. In cases with residual adenocarcinoma, the majority of the cases (9/11, 88%) do no have apparent treatment effects. Two cases showed nuclear pyknosis. In summary, we report the histological findings in benign and malignant prostatic tissues after HIFU treatment. These findings include a spectrum of morphological changes ranging from apparent necrosis to more subtle cellular damage can be observed in benign prostatic tissue after HIFU treatment. There were minimal morphologic changes in residual adenocarcinoma after HIFU treatments. CONCLUSION: The pathologist should be aware of common histologic findings in prostatic biopsies after HIFU treatment. We recommend routine reporting of Gleason scores in post-HIFU needle biopsies.