嚢胞形成を伴った前立腺癌の1例

Abstract

73歳男.排尿困難, 残尿感を自覚していた.狭心症発作で入院中に施行した腹部超音波断層法(US)で, 骨盤腔内膀胱後方に嚢胞性腫痛を指摘された.嚢胞形成を伴う前立腺癌を疑い, 経直腸的超音波(TRUS)ガイド下に経会陰的嚢胞内容液試験吸引及び経直腸的前立腺針生検を施行した.針生検の結果, 左側の膀胱頸部及び精嚢付近の前立腺組織から中分化型腺癌が検出された.嚢胞形成を伴う前立腺癌と診断し, 全身麻酔下に恥骨後式前立腺全摘除術を施行した.術後経過は良好で, 1ヵ月後にPSA値が0.03ng/mlまで低下した為, 補助療法を施行せずに退院し, 同年に人工肛門閉鎖術を施行した.術後10ヵ月を経過した現在, 尿失禁や排尿困難はなく, 直腸を含めて明らかな局所再発, 遠隔転移は認めず, PSAの上昇も認めていない

A 73-year-old man with the complaint of dysuria of 2 years' standing was admitted to our hospital for further examination of an intrapelvic cystic mass, 8.6 cm in diameter, detected incidentally by abdominal ultrasonography. The serum concentration of prostate specific antigen (PSA) was elevated to 44.9 ng/ml. Pelvic computed tomography (CT) and magnetic resonance imaging (MRI) revealed a cystic mass with an irregular thick cyst wall posterior to the urinary bladder originating from the prostate. Transrectal needle biopsy presented a moderately differentiated adenocarcinoma of the prostate. The bloody fluid of the cyst obtained by transperineal aspiration contained a significantly increased level of PSA, but no cancer cells were detected by cytological examination. Total prostatectomy was performed under the diagnosis of clinical stage C (cT3N0M0) prostate cancer. Pathological diagnosis was that cancer cells were present in the prostate tissue and had partly infiltrated the cyst wall. These results suggest that the present cyst was associated with the development of prostate cancer as a pseudocyst without an epithelial lining. The patient has remained free from the disease for over ten months. We review 56 cases of this rare condition that have been reported in Japan.