十二指腸の非腫瘍性びまん性病変の形態からみた鑑別診断

Differential Diagnosis of Non-neoplastic Diffuse Lesions in the Duodenum

要旨　十二指腸のびまん性病変の診断には，球部にとどまらず，下行部からVater乳頭部，さらには水平部の一部まで常に観察することを心がける必要がある．今回，非腫瘍性びまん性変化を来す疾患を粘膜異常を示すもの，狭小化を示すもの，拡張を示すものに分けて鑑別点について整理した．いずれの疾患も比較的まれである．十二指腸炎は胃の急性病変に随伴して臨床で遭遇することが多いが，十二指腸に限局する原因不明の非特異性の場合もある．また頻度の低い疾患としてはCrohn病，潰瘍性大腸炎などの炎症性疾患と併存するものや，アミロイドーシス，Schönlein-Henoch紫斑病，膠原病などの全身性疾患に伴うものがあり，鑑別には他臓器の変化や臨床症状を考慮すべきである．Kerckringひだの肥厚や消失，粘膜面の顆粒状変化やびらんなどは内視鏡で観察し，進行すれば狭窄や拡張の範囲をX線で描出し，生検を加えて十二指腸のびまん性病変を的確に診断していく．

　To diagnose diffuse lesions of the duodenum, it is necessary to observe the whole of the duodenum carefully, not only the duodenal bulb but also the second and third portion of the duodenum during the routine endoscopic examination. In this paper, we try to establish the differential diagnosis of non-neoplastic diffuse lesions of the duodenum. The endoscopic and radiographic findings of the diseases are divided into three groups; abnormal mucosal pattern in the duodenum, narrowing and dilatation of the duodenum. These findings in each group were discussed. It is very important to recognize faint granular and erosive changes of the duodenal mucosa in inflammatory bowel diseases (e.g., Crohn's disease), amyloidosis, Schönlein-Henoch purpura and collagen disease. A circumferential narrowing in the duodenum is generally caused by edema of the mucosa, scar formation and swelling of the Kerckring folds but differential diagnosis between benign and malignant stenosis is usually difficult. A biopsy is required in all cases to make an unequivocal diagnosis. Duodenal dilatation is more often the cause of functional disturbances (e.g., acute pancreatitis, scleroderma) than mechanical obstruction.