进展期胃癌胃壁浸润CT“分层征”的病理学基础

Invasion of Gastric Wall of Adanced Gastric Cancer: Pathological Basis of Its "Laminated Sign" on CT

目的 探讨进展期胃癌胃壁浸润CT分层征象的病理学基础。方法 31例病理证实的进展期胃癌 ,均作了胃肠造影及螺旋CT扫描。术后胃标本牵拉固定后 ,放射状象限取材 ,作病理对照观察。结果 动脉期、非平衡期及平衡期可见病灶分层情况分别为 35 .5 %、19.4%及 12 .9%。①病灶分两层 ,其低密带清晰 ,密度均一者有 11例 ,系黏膜下层癌细胞浸润及纤维组织广泛增生 ,使黏膜下层致密、增厚 ,肌层结构完整 ,仅在肌束间有癌巢形成。②病灶虽分两层 ,但其低密带不均 ,内可见条索影者 7例 ,为黏膜下层坏死、肿瘤细胞分泌的黏液及少量纤维组织增生构成。③病灶分三层者 2例 ,分四层者 1例 ,CT表现为“靶征” ,是癌组织树根状从黏膜下层浸润至肌层的肌纤维束之间所致。结论 进展期胃癌螺旋CT三期扫描可清楚地观察病灶分层 ,与病理对照 。

Objective To explore the pathological basis of CT 'laminated sign'about gastric wall invasion of advanced gastric cancer. Methods 31 patients underwent the double contrast examination of gastrointestinal tract and spiral CT scan. All cases were testified by pathology. Postsurgical specimens were fixed. Radial quadrant sampling, and then pathology control studying. Results The focal stratification was seen in aterial phase, nonequilibrium phase and equilibrium phase (35.5%, 19.4% and 12.9%, respectively). ①Foci of 11 cases were showed two layers, in which their low density bands were distinct and their densities were homogeneous. It was because of cancer cell invasion of submucous layer and extensively proliferation of fibrous tissue that made submucous layer condense and thicken. Muscular layer structrue was intact, but cancer nests were formulated in the middle of muscle bundles. ②Foci of 7 cases were showed two layers, in which low density bands were heterogeneous and cord shadows were seen. They were composed of submucous layer necrosis, mucus secreted by tumor cells and a few proliferation of fibrous tissue. ③Foci of 2 cases were showed three layers, and focus of 1 cases was showed four layers, 'target sign' was seen on CT. It was because of cancer tissue arborescently invaded from submucous layer to the middle of muscle fiber bundles. Conclusion Triphased scan of spiral CT can clearly show focal stratification in advanced gastric cancer. Accuracy of tumor staging on CT is improved by virtue of pathology control study.