A case of dermatomyositis associated with prostatic carcinoma : a case report

69歳男.主訴は食欲不振, 顔面の発疹.入院時, 顔面全体, 後頸部及び手背に浮腫性紅斑を認めた.筋無力感があり, 立ち上がり困難であった.皮膚筋炎を合併した前立腺癌が疑われ, 経直腸エコー下系統的前立腺針生検及び大腿四頭筋生検を施行した.前立腺組織では8ヶ所中4ヶ所でpoorly-differentiated adenocarcinoma, Gleason score 5+5=10が検出され, 筋組織では筋肉の壊死と再生像といった筋炎の所見を認めた.また, 画像所見より前立腺癌(T4N1M1)と診断された.諸治療を行ったが全身状態悪化にて初診1年ヵ月後に死亡した.著者等が検索した限り, 前立腺癌と皮膚筋炎との合併症例は本邦では3例あるのみで, 本症例は4例目の報告であった
We report a case of dermatomyositis associated with prostatic carcinoma. A 69-year-old male was admitted to the Department of Internal Medicine with the chief complaint of general fatigue, appetite loss and facial anthema. Abdominal ultrasound demonstrated swollen periaortic lymph nodes and the margin of prostate was unclear. Prostatic carcinoma was suspected based on digital rectal examination, so he was admitted to our department. Serum prostate specific antigen level was 190 ng/ml. He was examined by a dermatologist because of deterioration of anthema. Dermatomyocitis was demonstrated by dermatoses (edema erythema at face, neck and limbs, nail fold thrombosis and poikiloderma), high serum level of creatine phosphokinase and a decrease in muscular strength (especially at the proximal musculus). There was no interstitial pneumonitis or malignancy of the digestive system. On needle biopsy of the prostate and quadriceps femoris muscle, prostatic carcinoma (poorly differentiated adenocarcinoma, Gleason score 5 + 5) and myositis were suspected. The stage of prostatic carcinoma was T4N1M1. The patient was treated by administration of diethylstilbestrol phosphate and prednisolone for prostatic carcinoma and dermatomyositis, respectively, but he died of multiple metastasis of the tumor 1 year and 5 months later. Dermatomyocitis is associated with malignancy more frequently than any other collagen disease. In Japan, it is frequently complicated by gastric, lung and mammory cancers, but rarely by prostatic carcinoma. To our knowledge, this is the fourth case of prostatic carcinoma associated with dermatomyocitis in Japan.