胃粘膜内印環細胞癌における二層構造とリンパ節転移との関連性

Effect of Double-layer Structure in Intramucosal Gastric Signet-ring Cell Carcinoma on Lymph Node Metastasis

要旨●胃印環細胞癌は，HE染色で豊富な粘液から成る明るい表層と，弱好酸性細胞質の細胞から成る暗い深層の二層構造を示すことがある．この構造内の粘液形質は，正常胃固有腺に類似した分化極性を示す．粘膜下層浸潤癌ではこの構造が少ないことから，二層構造破壊がリンパ節転移リスク因子である可能性を考え，胃粘膜内印環細胞癌310例を対象に組織学的因子とリンパ節転移の関連性を検討した．単変量解析では腫瘍長径>20mm，潰瘍あり，二層構造なしの三因子が，多変量解析では二層構造なしが転移リスク因子であり，脈管侵襲・潰瘍なしであれば腫瘍長径が20mmを超えても，二層構造が保たれていればリンパ節転移は認めなかった．

　Signet-ring cell carcinoma（sig-GC）often exhibits a double-layer structure（DLS）in the intramucosal layer, reflecting its functional differentiation into normal gastric glands. It is hypothesized that the loss of differentiation leads to disruption of the DLS, accounting for the development of lymph node metastasis（LNM）. We aimed to elucidate the association between the histologic features of sig-GC, including the DLS, and LNM and to determine the LNM-negative condition in patients with pT1a（M）sig-GC. We reviewed the pathologic data of 310 patients with intramucosal sig-GCs who underwent gastrectomy with lymph node dissection. By univariate analysis, a tumor size of >20mm, presence of the ulcer（UL）, and absence of the DLS were significant risk factors for LNM. By multivariate logistic regression analysis, only absence of the DLS was a significant risk factor for LNM. Moreover, patients with a tumor size of >20mm that exhibited a DLS in the absence of UL did not develop LNM.