短期間に急速な直腸浸潤が認められた未治療前立腺癌の1例

Abstract

A case with non-treated prostate cancer, which showed rapid rectal involve- ment in 3 months, is reported. A 62-year-old man visited our out-patient clinic for periodic follow-up studies for urolithiasis in, August 1997. In spite of having no symptoms on urination, a Tandem-R (RIA) prostatic specific antigen (PSA) level was 5.8 ng/ml. Although transrectal ultrasonography demonstrated no signs of malignancy, endorectal MR imaging done in November showed a low intensity area of 15 mm in diameter in the right peripheral zone of the prostate. Stage T2 prostate cancer was strongly suspected. At the time of needle biopsy of the prostate done in 3 months, a solid mass was detected on ultrasonography at the posterior, distal side of the prostate, which was clearly distinguished from the prostate. The selectively obtained biopsy specimens from the prostate and the mass were histopathologically diagnosed as poorly differentiated adenocarcinoma. Thick- ening of the rectal wall was recognized in MR imaging. From the findings of recto- sigmoidal colonoscopy and immunohistochemical staining with PSA of both biopsy speci- mens, the rectal mass was judged to be an invasion of prostate cancer. With a combination therapy with maximum androgen blockade and radiation, the tumor was reduced in size and PSA level decreased from 73 ng/ml at the therapy initiation to 0.3 ng/ml. Although prostate cancer, in general, shows slow growth, a prompt diagnosis might be required, even when early prostate cancer is suspected.