ATLの消化管病変の臨床像

Clinical Features of Gastrointestinal Involvement in Patients with Adult T-cell Leukemia

要旨　ATLの消化管病変として腫瘍細胞の消化管浸潤病変について，自験例22例の画像所見を画像所見と密接に関係する腫瘍細胞の浸潤・発育進展様式の観点から検討し，肉眼像を分類し，その特徴について症例を呈示し述べた．胃では，画像検査の施行された22例中18例，小腸では17例中9例，大腸では16例中9例に浸潤がみられた．ATLの消化管浸潤は広範囲で，かつ高度に及び，多発性またはびまん性の浸潤病変が多い傾向にあった．画像所見の検討により浸潤・発育進展様式とその肉眼像を基本的に以下の3つに分類した．①腫瘍細胞が腫瘤をつくらず消化管壁を連続性にびまん性に浸潤するタイプで，肉眼像としては粘膜面の凹凸が目立たない平坦病変を呈す―びまん浸潤型（表層型）．②腫瘍細胞がリンパ装置に浸潤し腫瘤を形成するタイプで，肉眼像としてはMLP様の多発性の隆起性病変を呈す―多発結節型．③腫瘍細胞が多数のリンパ装置に浸潤し小さな腫瘤を形成するタイプで，肉眼像としてはたこいぼびらん様の小隆起がびまん性に多発した病変を呈す―多発びまん浸潤型．高度に白血化した症例は主として①の，その他の症例は主として②または③の浸潤・発育進展様式をとり，その肉眼像を呈すると考えた。ATLの消化管浸潤病変は腫瘍細胞の消化管への浸潤・発育進展様式および浸潤の程度が密接に関係し，多彩な肉眼像を呈すると考えた．更に消化管原発のATLの可能性について自験例を呈示し述べた．またATLの消化管の日和見感染症として，糞線虫とIsospora belliの感染症の症例を呈示した．

　In 22 adult T-cell leukemia (ATL) patients with gastrointestinal involvement, and who were treated at our institution, tumor cell infiltrative lesions of the gastrointestinal tract were investigated. Radiographic and endoscopic findings were examined with respect to manner of tumor cell infiltration and its growth/expansion, which are factors closely reflected in the images. Further, macroscopic features were classified by the manner of tumor cell infiltration and growth/expansion and these characteristics were described referring to the cases. Tumor cell infiltration was detected in the stomach in 18 of 22 patients, in the small intestine in nine of 17 patients and in the large intestine in nine of 16 patients who were examined. ATL had highly infiltrated a wide area in the gastrointestinal tract and infiltrative lesions tended to be multiple or diffuse. Based on findings on the imaging, the manner of tumor cell infiltration and growth/expansion and the macroscopic features were classified into the following three types ; 1) diffusely infiltrating type (superficial type) : tumor cells diffusely infiltrate the continuous wall of the gastrointestinal tract without forming a mass. The lesions appear flat without noticeable irregular mucosa on macroscopic observation, 2) multiple nodular type : tumor cells infiltrate lymphoid follicles and form tumors, showing multiple protruded lesions like multiple lymphomatous polyposis (MLP) as a macroscopic feature, and 3) multiple and diffusely infiltrating type : tumor cells infiltrate a number of lymphoid follicles and form innumerable small elevated lesions. As a macroscopic feature, small protruded lesions resembling erosive gastritis are extensively observed.

　Highly leukemic cases mainly showed the type of infiltration and growth/expansion described in 1) and macroscopic features reflected this type of infiltration and growth/expansion. Other cases mainly showed the features described in 2 ) or 3 ) . Infiltrative lesions in the gastrointestinal tract in ATL may be closely associated with types of tumor cell infiltration of the gastrointestinal tract and growth/expansion as well as with the degree of infiltration, both of which are reflected in various macroscopic features. Further, the possibility of primary ATL in the gastrointestinal tract was described as shown by a case treated at our institution. Furthermore, ATL cases with opportunistic infection with Strongyloides stercoralis or Isospora belli were presented.