Abstract
Esophageal carcinosarcoma (EC) is a rare malignant tumor, accounting for 0.5–2.8% of esophageal cancers. Most are advanced cancers that are detected as polypoid lesions and are treated with multidisciplinary therapy with a focus on surgery. However, endoscopic findings, pathological findings, and long-term outcomes of early-stage EC are often unclear because there are very few reported cases. This paper reports three cases of EC confined to the mucosal layer. The macroscopic type of all tumors was polypoid lesion with a slightly depressed lesion. All cases were clinically diagnosed as invasive cancer before treatment. Pathological diagnosis of tumor depth showed that one case had invaded the lamina propria mucosae, and two cases had invaded the muscularis mucosae (MM). One case of diagnosed MM had lymphoid invasion and lymph node metastasis to the upper mediastinum. After 1 year, although adjuvant treatment had been administered, there was lymph node recurrence in the left upper clavicle, and thus chemoradiation therapy was performed. Two other cases survived without recurrence. Early-stage EC is characterized by polypoid lesions with a slightly depressed lesion, and it is challenging to predict the histology on biopsy. Furthermore, it is difficult to determine the depth of invasion in the MM and submucosal layer in squamous cell carcinoma by endoscopy alone, and hence depth diagnosis by multiple modalities should be considered.