Clinicopathologic Study of Esophageal Squamous Cell Carcinoma Confined to the Mucosa

The authors studied patients with esophageal squamous cell carcinoma confined to the mucosa (ESCM) with respect to various clinicopathologic factors to investigate the course of invasion of very early-stage esophageal cancers. A total of 74 patients with ESCM were studied. Fifty of these patients had tumor invasion of the basement membrane confined to the lamina propria mucosae (m2 cancer), and 24 patients had tumor invasion of the muscularis mucosa (m3 cancer). All lesions were investigated with regard to clinicopathologic factors such as tumor differentiation, pattern of invasion, endoscopic morphology, and inflammatory response. The patients were divided into groups of 8 patients with positive lymphatic invasion, lymph node involvement, or both (Inv[+] group), and a group of 66 patients with no lymphatic invasion or lymph node involvement (Inv[−] group). The inflammatory response was evaluated on the basis of lymphocyte infiltration at the tumor invasion front and lymphocytic follicles beneath the tumor invasion front. Mean lesion size was significantly greater in the Inv(+) group than in the Inv(−) group (p < 0.05). However, there was no significant difference in the mean area of invasion of the lamina propria mucosae or deeper between the Inv(+) group and Inv(−) group. Patients with m2 cancer had a significantly higher rate of high-degree lymphocytic follicles than those with m3 cancer (p < 0.01). In patients with m2 cancer, the mean area of invasion of the lamina propria mucosae in patients with high-degree lymphocytic follicles was significantly greater than that in patients with low-degree lymphocytic follicles (p < 0.05), whereas there was no significant difference in mean lesion size between patients with high-degree and low-degree lymphocytic follicles. In patients with ESCM, lesion size was an important risk factor for lymphatic invasion and nodal involvement, lymphocytic follicles were prominent beneath the front of relatively broad cancer invasion, and lymphocytic follicles were less common with deeper cancer invasion.