前立腺放射線療法後, 前立腺壊死を伴った壊疽性膿皮症の1例

Abstract

76歳男.主訴は排尿困難, 頻尿.前立腺生検ではGleason 4+2の腺癌を両葉に認め, 臨床病期T3aN0M0の前立腺癌と診断された.前立腺に対し放射線療法を施行した.排尿困難, 膀胱刺激症状, 無菌性膿尿が出現し, 尿閉となった為TUR-P施行した.手術時の内視鏡所見では前立腺組織は壊死組織で覆われており, 後部尿道は膀胱頸部に粘膜がかろうじて残っているのみであった.皮膚病変が特徴的な無菌性噴火口状潰瘍を呈するようになったことより壊疽性膿皮症の可能性を指摘された.皮膚の生検では真皮内に肉芽組織の形成が著明で中心部にはabscess様の好中球浸潤がみられた.壊疽性膿皮症の診断のもとステロイドの内服を開始した.熱発の改善とCRPの低下を認め, 右上肺野の腫瘤はドレナージとステロイド内服により空洞化し, 皮膚潰瘍は周囲より特有な瘢痕を形成しながら治癒傾向にあった.骨盤部CTでは前立腺部は一部壊死組織が認められるようであるがステロイド開始前より明らかに縮小し, 海綿体は周囲に炎症所見が見られたがlow densityな部分は非常に縮小していた

A 76-year-old man complained of difficulty in urination and miction pain with abacterial pyuria after radiation therapy for prostate cancer. Transurethral resection of the prostate was performed and histopathologically widespread necrosis was observed in the prostate. Thereafter retention of urine and fever occurred and computed tomography scan revealed an abscess of the penile corpus. The abscess was drained, but the fever continued. He developed an abacterial lung abscess and abacterial necrotic ulcerating lesions on his back, his left leg and his lower abdomen. Macroscopic findings demonstrated typical features of pyoderma gangrenosum. Steroid treatment was initiated and the response to steroid therapy was dramatic. Finally urinary diversion using an ileal conduit was performed. We found few cases of pyoderma gangrenosum involving lesions other than those of the skin in the literature. This is the first report of pyoderma gangrenosum involving the prostate gland after radiation therapy for prostate cancer.