3) 大腸 (1)腫瘍の pit pattern 分類

Pit Pattern Classification in Colorectal Neoplasms

要旨　pit patternはI，II，IIIs，IIIL，IV，V型の6型に分類され，病理組織や癌の深達度診断とよく相関することより，診断や治療方針決定に有用である．I型は正常粘膜である．II型は大型の星芒状pitで，過形成性ポリープである．IIIsは小型の類円形pitで，陥凹型病変に特徴的なpatternである．IIILは線状の細長いpitで，隆起型や表面隆起型の腺腫に最も多く認められ，IV型は分枝を伴うもの，脳回転状や絨毛状のものを指し，管状絨毛状腺腫や絨毛状腺腫に多い．厚生労働省の班会議においてV型pit patternの亜分類が改訂された．VN型pit patternおよびVI高度不整をsm massive癌の指標と仮定した場合，高い正診率が得られた．

　The openings of the colonic crypts are referred to as "pits", and the specific arrangement of the openings of the glands in various kinds of lesions which can be observed with a magnifying endoscpe is called the "pit pattern". The pit patterns are classified into I, II, IIIs, IIIL, IV, VI, and VN. Pit pattern analysis is useful to differentiate between neoplastic and non-neoplastic lesions because if the pit pattern is type I or type II, the lesion is almost definitely non-neoplastic. The lesions with type IIIs, IIIL or IV pit pattern can be treated endoscopically because they are adenomatous but not invasive. Those with type VN pit pattern should be treated surgically because they are definitely invasive and may have nodal metastases. The lesions with type VI encompass a variety of lesions from benign adenoma to invasive carcinoma. Therefore lesions with type VI pit pattern are first treated endoscopically, and additional surgical colectomy and lymph node dissection is considered after the histological analysis of the excised specimen.