腸重積症で発症し特異な病理像を示した空腸ポリープの1例

Jejunal Polyps with Unique Histopathological Characteristics Causing Invaginations, Report of a Case

要旨　先天性虹彩欠損症を有する16歳の女性．嘔気，嘔吐を主訴として入院．上部消化管透視，内視鏡検査，腹部CTなどにより口側空腸に腸重積症を見出した．手術の結果，重積部を中心として約20cmにわたり多発性のポリープを認めた．組織学的には粘膜上皮細胞の異型性は認められなかったが，粘膜下層の浮腫，粘膜上皮の絨毛の消失・癒合・乳頭状増生，表層上皮の過形成など多彩な所見が認められ，従来報告されている腸腫瘍のいずれとも合致しなかった．リンパ球を用いた染色体分析では異常を認めなかったが，近年，無虹彩症とWilms腫瘍の合併例が多いことが報告されており，ポリープの発生に遺伝子異常が関与している可能性も考えられた．

　A 16-year-old female with congenital aniridia was admitted to our hospital because of upper abdominal pain, repeated nausea and vomiting. The upper gastrointestinal x-ray series and endoscopic examination demonstrated a Yamada type Ⅳ polyp (diameter 3 cm approximately) in the jejunum 10 to 20 cm anal to the Treitz's ligament and obstruction of the lumen on the anal side of the polyp (Figs. 1 and 2). Ultrasonic and computed tomographic studies (Figs. 3 and 4) showed typical signs of jejuno-jejunal invagination with an intraluminal polyp at the leading point.

　Surgical operation was carried out. There were multiple polyps with a stalk or substalk within the jejunal lumen, 20 cm in length, around the invaginated portion. Adjacent portion of the jejunum, 30 cm in length, with the polyps was resected (Fig. 5).

　Histopathological studies showed formation of the protrusion caused by submucosal edema, adhesion and disappearance of the villi of muco-epithelium, papillaryform proliferation, hyperplasticity of surface epithelium, protrusion formed by stretching of the submucosal layer and partial erosion. There were no findings suggesting any epithelial atypia at all (Figs. 6 and 7).

　There have been no reports on jejunal polyps with such characteristic histopathological findings as in this case. It is well known that aniridia, which this patient also suffered from, sometimes complicates Wilms' tumor or some chromosomal aberrations. Therefore, it could be considered that chromosomal abnormalities are related to the occurrence of such unique polyps as seen in this case; in this particular case, however, we could not find chromosomal abnormalities.