特徴的な内視鏡所見を示し免疫組織染色にて診断しえた直腸子宮内膜症の1例

Typical Endoscopic Findings Combined with Immunohistochemical Analysis were Useful for Diagnosis of Endometriosis of the Rectum, Report of a Case

要旨　患者は40歳代，女性．血便を主訴に来院した．下部消化管内視鏡検査を施行したところ，直腸Ra〜Rs右壁側に径20mm大の表面やや不整な粘膜下腫瘍様隆起を認め，表層の一部に特徴的な発赤調の結節状隆起を伴っていた．EUSでは，病変部の第4層の肥厚を認め，肥厚部と連続して直腸壁外に径20mm大の内部に一部高エコーな領域を含む低エコー腫瘤が描出され，発赤調の結節部では第3層が途絶していた．生検組織では腺癌も疑われたが，特徴的な内視鏡像から本疾患を疑い，免疫染色を加えることで腸管子宮内膜症と診断した．診断後GnRH（gonadotropin-releasing hormone）アゴニスト療法を開始した．3か月後の下部消化管内視鏡検査では病変の退縮を認めた．

　A woman in her 40s visited our hospital because of hematochezia. Colonoscopy revealed a 20mm diameter submucosal-like tumor in the right anterior wall of the rectum. The surface of the tumor was slightly irregular, and there was a reddish nodule on the surface of the tumor. Endoscopic ultrasonography revealed a thickened 4th layer with an enclosed hyperechoic nodule and a 20mm hypoechoic mass outside the rectal wall. The 3rd layer was disrupted below the reddish nodule on the surface. Although adenocarcinoma was detected by HE staining of a biopsy specimen, the mass was diagnosed as endometriosis of the rectum because it was positive for estrogen receptor, progesterone receptor, and vimentin by immunostaining. The patient received gonadotropin-releasing hormone agonist treatment, and the tumor regressed in size three months after initiation of therapy.