笹沼 英紀

BACKGROUND: Capicua transcriptional repressor (CIC) -rearranged sarcoma is characterized by small round cells, histologically similar to Ewing sarcoma. However, CIC-rearranged sarcoma has different clinical, histological, and immunohistochemical features from Ewing sarcoma. It is important to differentiate between these tumors. CASE PRESENTATION: The patient is a 44-year-old man with a duodenal tumor diagnosed in another hospital who presented with a history of melena. Laboratory studies showed anemia with a serum hemoglobin of 6.0 g/dL. He was hospitalized and gastrointestinal bleeding was controlled successfully with endoscopy. However, he suffered from appetite loss and vomiting and progression of anemia a few weeks after presentation. Upper gastrointestinal endoscopy showed a circumferential soft tumor in the second portion of the duodenum and the endoscope could not pass distally. Computed tomography scan showed a greater than 10 cm tumor in the duodenum, with compression of the inferior vena cava and infiltrating the ascending colon. A definitive pathologic diagnosis could not be established despite four biopsies from the tumor edge. Due to gastrointestinal obstruction and progression of anemia, a pylorus-preserving pancreaticoduodenectomy with partial resection of the inferior vena cava and right hemicolectomy was performed as a complete tumor resection. The tumor was diagnosed as a CIC-rearranged sarcoma, but 2 months postoperatively local recurrence and distant metastases to the liver and lung were found. The patient died 3 months after surgery. CONCLUSIONS: Although the only definitive treatment for CIC-rearranged sarcoma is surgical resection, the CIC-rearranged sarcoma is highly malignant with a poor prognosis even after radical resection. More research is needed to establish optimal treatment strategies.

BACKGROUND: Thymomas are typically slow-growing tumors and AB type thymomas are considered no/low risk tumors with a better prognosis. Extra-thoracic metastases are extremely rare. To the best of our knowledge, no patient with an isolated splenic metastasis from a thymoma has been reported. We report a patient who underwent laparoscopic splenectomy for a slow-growing, isolated splenic metastasis, eight years after thymectomy. CASE PRESENTATION: The patient is a 78-year-old man. Eight years previously, the patient underwent extended thymectomy and postoperative radiation therapy for a thymoma. Five years after thymectomy, a nodule appeared in the spleen, and the lesion enlarged gradually for three years thereafter. The patient was referred for further examination and treatment. Computed tomography scan showed a sharply circumscribed 50 mm tumor slightly hypodense and heterogeneous lesion in the spleen. On T2-weighted images on Magnetic Resonance Imaging, the tumor had high intensity, equivalent to or slightly lower than that on T1-weighted images, and no decrease on diffusion-weighted images. The tumor was multinodular and showed a low-signal spoke-wheel sign in the margin, enhanced gradually in the dynamic study. Positron emission tomography-CT scan, showed relatively low accumulation. Surgical resection was undertaken, and pathological examination showed metastatic thymoma. The patient is without recurrence and has no other symptoms three years after splenectomy. CONCLUSIONS: This is the first report of an isolated splenic metastasis from a thymoma. Further cases are needed to standardize this surgery for such lesions.

症例は70歳の男性で，塵肺（エリスロマイシン内服），慢性腎不全（血液透析中），ANCA関連血管炎（プレドニゾロン内服）の併存症があり，定期CT検査で肝腫瘤を認め当院を紹介受診した．CTで肝S3に単純で低吸収，動脈相で濃染，門脈相でwash outされる腫瘤を認めた．MRIではT1低信号・T2高信号，diffusionで拡散低下，肝細胞相でdefectを認め，エコーではhaloや後方エコーの増強を伴っていた．画像所見から肝細胞癌と術前診断し，腹腔鏡下肝S3部分切除術を施行した．腫瘍は大きさ40×37×33mmの被膜を有する壊死組織で，viableな細胞は認めなかった．中心壊死・硝子化線維性組織・弾性線維を特徴とする肝孤立性壊死性結節を鑑別としたが被膜に弾性線維がなく，肝細胞癌完全自然壊死を最終診断とした．自然壊死の機序として透析による血流障害，エリスロシンやステロイドの薬剤関与が考えられた．

症例1は30歳男性で、発熱と左腹部痛で来院した。CTで感染性Walled-off necrosis(WON)と診断し、保存的治療を行ったが、症状ならびに炎症所見の改善を認めず、インターベンション治療目的に当院転院となった。造影CT所見から壊死物質を主成分とした感染性WONと診断し、小切開Videoscope補助下に後腹膜経路でネクロセクトミーを行った。1回のネクロセクトミーで炎症所見とCT所見は速やかに改善し、追加の処置は不要となった。左後腹膜のドレーンは留置したまま入院40日目に退院した。症例2は34歳男性で、急性膵炎の診断で保存的治療が開始され、退院約2週間後に間歇的腹痛と発熱で来院し、炎症反応高値、CTで感染性WONと診断され再入院した。造影CT所見から膵体尾部の壊死物質を主成分とする左側感染性WONと診断し、腹腔経路で小切開Videoscope補助下にネクロセクトミーを行った。その後、右側WON増大による閉塞性黄疸が出現し、開腹ネクロセクトミーと胆道ドレナージが必要となった。症状出現から7ヵ月後、ERCPで左右肝管にERBD tubeを留置し退院した。

<p> 症例は64歳の女性．職域健診で便潜血が3年連続陽性だったが放置し，さらに，立ちくらみと排便時痛も出現したが放置していた．その後，貧血も指摘されて受診し，進行直腸がん，早期結腸がんと診断され，これらの治療前精査にて胆嚢がんも発見された．早期結腸がんに対して内視鏡的治療が予定されたが，その前処置で腸閉塞となった．人工肛門が造設され，その後，結腸がんに対する内視鏡的治療，胆嚢がんの手術が施行され，現在，直腸がんに対して化学療法が施行されている．</p><p> 近年，大腸がんは増加傾向にあるが，大腸がん検診の精検受診率は低い．また，地域検診に比し職域検診は精検受診率が低い．大腸がんの知識の啓発は受診意識の向上に繋がり，適切な受診勧奨と合わせて重要である．</p><p> 高齢化，画像診断の進歩に伴い，重複がんが増加傾向にある．大腸胆嚢重複がんは稀であるが，やはり増加傾向にある．がん検診でも，問診，理学・検査所見からがん好発・多発因子の有無を確認することが重要であり，健診医療従事者にも重複がんに関する知識は必要である．</p>