Misdiagnosis of an elevated lesion in the esophagus: A case report

BACKGROUND: Esophageal carcinosarcoma (ECS) is a rare biphasic tumor and a type of esophageal malignancy, which presents as protruding or elevated lesions. ECS patients are often not hospitalized until they have severe dysphagia. ECS is easily misdiagnosed as a benign tumor due to its atypical characteristics under endoscopy. With the popularization of endoscopic treatment, these patients are often referred to endoscopic treatment, such as endoscopic submucosal dissection (ESD). However, there is a lack of consensus on the endoscopic features and therapies for ECS. Here, we report a case of ECS and discuss the value of endoscopic diagnosis and therapeutic strategies. CASE SUMMARY: A 63-year-old man was admitted to the hospital with dysphagia. During the endoscopic examination, an elevated lesion was found with an erosive and hyperemic surface covered with white pseudomembranous inflammation. Endoscopic ultrasonography (EUS), biopsies, and enhanced thoracic computed tomography were performed, suggesting that it was a benign lesion and located within the submucosal layer. This lesion was diagnosed as a fibrovascular polyp with a Paris classification of 0-Ip. The patient was then referred to ESD treatment. However, the post-ESD pathological and immunohistochemical study showed that this lesion was ECS with a vertical positive margin (T1b stage), indicating that we made a misdiagnosis and achieved a noncurative resection. Due to the potential tumor residue, additional open surgery was performed at the patient's request. In the postoperative pathological study, no tumor remnants or metastases were discovered. The patient was followed for 1 year and had no recurrence. CONCLUSION: ECS can be misdiagnosed at the initial endoscopy. EUS can help to identify the tumor stage. Patients with T1b stage ECS cannot be routinely referred to ESD treatment due to the high risk of metastasis and recurrence rate.