希少な特殊型胃癌の内視鏡診断

Endoscopic Features of Rare and Special Types of Gastric Cancer

要旨●特殊型胃癌のうち，特に希少な腺扁平上皮癌，扁平上皮癌，未分化癌，絨毛癌，癌肉腫，浸潤性微小乳頭癌について述べる．いずれも一般的な胃癌と同様に男性に多いが，進行が早いためか進行癌で見つかることが多い．癌肉腫は隆起を呈することが多いが，それ以外は2型，3型のような潰瘍を伴うことが多い．まれなため症例が少なく，進行した状態で見つかることが多いため，初期段階の内視鏡像など不明なことが多く，今後症例が集積されることを期待したい．

　Herein we discuss various special types of gastric cancers, including extremely rare adenosquamous carcinoma, squamous cell carcinoma, undifferentiated cancer, choriocarcinoma, carcinosarcoma, and invasive micropapillary carcinoma. All of these are common in males, but are usually detected at advanced stages, most likely due to their rapid progression. Carcinosarcoma frequently presents with a ridge, but others, such as Bormann's type 2 or type 3, are usually accompanied by ulcers. Since they are rare and discovered at advanced stages, endoscopic images of the initial stages are unknown, and we hope that more cases will be accumulated in the future so that they can be studied further.