野田 弘志

Mesenteric leiomyosarcoma is a rare disease with poor prognosis. Previously, mesenteric leiomyosarcoma was not differentiated from gastrointestinal stromal tumor (GIST), which is the most common mesenchymal tumor of the gastrointestinal tract, and several cases of GIST may have been misclassified as mesenteric leiomyosarcoma. Thus, the actual clinicopathological characteristics of mesenteric leiomyosarcomas remain unclear. We herein describe a case of leiomyosarcoma arising in the descending mesocolon in a patient who developed metachronous liver metastasis. A 76-year-old woman reported a mass in her left upper abdomen. Computed tomography imaging revealed a low-density tumor adjacent to the descending colon. The patient underwent surgery and the tumor was resected along with part of the descending colon. Immunohistochemical differential diagnosis revealed that the tumor was positive for smooth muscle actin and desmin, and negative for CD117 (c-KIT) and S-100, which are characteristic of gastrointestinal leiomyosarcoma. A single liver metastasis developed 24 months after the operation. The patient underwent curative resection of the metastatic lesion. Sixteen months following surgery for the liver metastasis and 40 months after the initial removal of the primary lesion, the patient remains disease-free. The prognosis of leiomyosarcoma remains poor and standardized chemotherapy for this rare disease has not yet been established. Early diagnosis and surgical removal of the tumor is the only potentially curative option for liver metastasis of mesenteric leiomyosarcoma.

症例は78歳，男性．68歳時から多発肝嚢胞と腎嚢胞を指摘されていた．2007年12月，経過観察のCTで多発肝嚢胞と一部嚢胞内に充実性腫瘤を認めたため精査加療目的に2008年3月当科紹介受診．腹部超音波で肝両葉に多発嚢胞を認め，左葉S3の嚢胞内と右葉S7の嚢胞内に乳頭状隆起性腫瘤があった．腹部CTでもS3とS7の嚢胞内に淡く造影効果を伴う軟部組織濃度の腫瘤を認めた．FDG-PETでは肝内に異常集積像を認めなかった．ERCP，MRCPではS3とS7の嚢胞と胆管との交通は確認できなかった．嚢胞性腫瘍を強く疑い，肝部分切除術を施行した．病理学的所見としてはいずれも多房性嚢腫であった．一部に認められた，壁の充実性部分は肥厚した嚢胞壁を形成する血管結合組織で，画像上で嚢胞内隆起性病変と考えた部分は嚢胞内出血による凝血塊と，その部分的な器質化であった．腺腫や癌を疑う所見はなかった．同時多発性で増大傾向のある肝嚢胞内出血の症例は極めて稀であり，若干の文献的考察を加えて報告する．<br>

【症例1】71歳,男性。平成19年に糖尿病と診断、腹部超音波検査(US)で膵腫瘍認め紹介受診。CTで膵頭体部に嚢胞性病変あり,主膵管の拡張および内部に壁在結節を認めた。病変は主膵管と交通があり,IPMCと診断。膵全摘術施行。術後腹水の貯留認めたが改善し,軽快退院となる。病理では慢性膵炎像を混じた急性出血性変化による嚢胞腔形成と診断された。 【症例2】59歳,男性。平成19年にアルコール性膵炎で他院に入院。CTとMRCPで膵頭部に多房性嚢胞性病変認め,紹介受診。USとEUS上病変は主膵管と交通があり,内部に壁在結節認め、分枝型IPMNと診断。膵頭十二指腸切除術施行。病理診断は慢性膵炎であった。術後問題なく,軽快退院となる。 【考察】膵嚢胞性病変の鑑別診断にはIPMN,MCT,SCT,仮性嚢胞,SPTなどがある。慢性膵炎後の仮性嚢胞はIPMNとの鑑別が困難なことがあり,注意が必要である

We herein report a rare case of a strangulated obstruction of the small intestine caused by a transomental hernia. A 66-year-old male was brought from another hospital by ambulance due to strangulated small bowel obstruction. He had no history of surgery. He had an acute onset of abdominal pain with nausea, vomiting and abdominal distension. Other symptoms were tachycardia, low blood pressure, abdominal tenderness in physical examinations, inflammatory changes, and metabolic acidosis in the blood analysis. Abdominal computed tomography showed a marked dilatation of the small intestine, which was poorly enhanced with massive ascites. In addition, no mesenteric vascular occlusion but the radial distribution of the mesentery anterior to the transverse colon was observed. A diagnosis of strangulated obstruction was made, and emergency surgery was performed. Intraoperatively, massive bloody ascites were observed and the small intestine was incarcerated through a hiatus of the greater omentum with necrosis. We performed an open incision of the hiatus to release the incarceration and then resected the necrotic portion. The postoperative course was favorable and the patient was discharged on hospital day 10. This case emphasizes the importance of internal hernias, including considering a transomental hernia as a potential cause of an interstinal obstruction in patients without a history of surgery.