膀胱放線菌症の1例

Abstract

55歳女.下腹部痛と腹部腫瘤を主訴とした.腹部CTで膀胱の左側に5×4cm大のenhanceされる内部不均一な腫瘤を認め, MRI強調像では膀胱筋層との境界が不明瞭な充実性腫瘤を認めた.悪性腫瘍も完全に否定できないと考え, 摘出術を施行した.手術所見では, 膀胱前腔に存在する腫瘤は子宮円索と正中臍索を巻き込んでいた.腫瘤は膀胱, 腹膜とは境界不明瞭であり, 膀胱頂部を含めて一塊に切除し, 回腸利用膀胱拡大術を施行した.病理組織学的所見では, HE染色で放線菌症に特有なsulfur granuleとよばれる菌塊が認められ, 周囲には炎症細胞浸潤があり膀胱筋層まで及んでいた.Gram染色では菌塊の辺縁に棍棒状構造を認めた.以上より, 微生物学的に菌の検出はできなかったが, 放線菌症と診断した.菌塊が切除し得ていたため, 術後1週間抗生剤の内服を行うことで, 経過良好であり術後10ヵ月の時点で再発を認めていない

A 55-year-old woman had complained of lower abdominal pain for 5 years. A computed tomographic CT scan and magnetic resonance imaging revealed a heterogeneous density mass on the left side of the bladder. CT-guided needle biopsy showed only inflammatory cell infiltration without histological diagnosis. To confirm the diagnosis, the mass was resected together with part of the bladder and peritoneum. On the cut surface, the mass was centrally pale yellow and adherent to the thickened hard wall of the bladder and peritoneum. Pathological diagnosis was chronic granulomatous inflammation with actinomycosis. This is, to our knowledge, the 12th case report of vesical actinomycosis in Japan. Although actinomycosis is very rare in urological field, abdominal actinomycosis should be considered as the differential diagnosis of any inflammatory abdominal mass.