Mucosal squamous cell carcinoma of the esophagus: a clinicopathologic study of 30 cases.

A clinicopathologic study was carried out on 30 patients with mucosal esophageal cancer (MEC). The depth of cancer invasion was subdivided histologically into three categories: m1 = carcinoma in situ (intraepithelial carcinoma) or carcinoma with questionable invasion beyond the basal membrane; m2 = cancer invasion confined to the lamina propria, and m3 = cancer reaching to or infiltrating into the muscularis mucosae. Lymph node metastases and lymphatic invasion were found only in the tumors reaching or infiltrating the muscularis mucosae (m3). The maximum histologic vertical extent of the tumors was more than 1 mm in 4 of 5 patients with lymph node metastasis or lymphatic invasion. None of the patients died of recurrent esophageal disease, and 3 of the 6 patients who had a second primary tumor died of this other malignancy. It is critical to distinguish between m1, m2 and m3 tumors to plan a treatment strategy, including an endoscopic mucosal resection.