十二指腸球部隆起性病変の鑑別診断―特に良・悪性の鑑別診断について

Differential Diagnosis of Polypoid Lesions in the Duodenal Bulb Based on Radiologic and Endoscopic Findings

要旨　上部消化管内視鏡検査5,335例における十二指腸球部隆起性病変の頻度および各疾患別頻度を検討した結果，その頻度は2.7％で，非特異性隆起性病変，異所性胃粘膜の順に多く，この二者で全体の77％を占めた．次いでX線および内視鏡検査が施行され球部に隆起性病変を認めた126例について，これらの所見に基づく新しい形態分類の提案を行い，各形態別の特徴について検討した．この分類は多発性3型と単発性4型に分けられ，前者はびまん性，顆粒状の胃小区様模様を呈するもの（A型），1～3mm大のびまん性ないし散在性細隆起（B型），そして4mm以上の表面平滑な無茎性小隆起（C型）であり，後者は表面平滑な無茎性ないし有茎性隆起（D型），中心陥凹を伴う表面平滑な無茎性ないし有茎性隆起（E型），結節状ないし分葉状の，無茎性ないし有茎性隆起（F型），そして胃小区様模様に類似した中心陥凹を伴う結節ないし分葉状の隆起（G型）である．多発性35例は悪性リンパ腫の1例を除きすべて良性であった．単発性91例の中で認めた悪性9例はカルチノイド，早期癌，転移性癌，悪性リンパ腫などであり，良・悪性の鑑別点は粘膜のびらんないし出血，中心陥凹辺縁の不整，短期間での増大傾向などであった．この分類を用いれば十二指腸球部隆起性病変の鑑別診断は容易であると考えられた．

　Five thousand three hundred thirty five patients underwent upper gastrointestinal endoscopic examination with biopsy. One hundred forty three patients with duodenal polypoid lesion (DPL) in the bulb (2.7% for all cases) were evaluated for the prevalence of each morphological featues. Non-specific polypoid lesion (NSPL) were the most common type, followed by heterotopic gastric mucosa (HGM). One hundred twenty six patients with DPL in the bulb, who underwent both radiologic and endoscopic examinations, were evaluated for their morphological characteristics using our classification. DPL could be classified into seven types (Types A-G), as shown in Fig. 2. In 35 multiple lessions (Types A-C), one patient had malignant lymphoma, but the rest had benign diseases (97%). Eighty two (90%) out of 91 single lesions (Types D-G) were benign and nine (10%) were malignant. The salient points in the differentiation between benign and maliganant diseases were the existence of erosion or hemorrhage of the mucosa, and marginal irregularity and rapid enlargement of a central depression.

　In conclusion, the existence of morphological variability of HGM is especially important to remember for the differential diagnosis of DPL. Our new, comprehensive classification of DPL, based on radiologic and endoscopic examinations, will contribute to the differentiation between malignant and begnign diseases.