Endoscopic diagnosis of early-stage primary esophageal small cell carcinoma: Report of two cases

BACKGROUND: Primary esophageal small cell carcinoma (PESCC) is a highly aggressive malignancy, and its detailed clinical behaviors have remained virtually unknown. Because of the rapid tumor progression, the diagnosis of esophageal small cell carcinoma at early stage is extremely difficult in clinical practice. Currently, only a handful of PESCC cases have been reported. CASE SUMMARY: Case 1: A 62-year-old man was diagnosed with an esophageal submucosal tumor by endoscopy. Endoscopic ultrasonography showed a 0.8 cm low echo nodule in the muscularis mucosa. As the patient refused to undergo endoscopic resection, neoplasia was detected by endoscopy 1 year later. Case 2: A 68-year-old woman was diagnosed as having an esophageal submucosal tumor by endoscopy at a local hospital. About 2 wk later, we performed endoscopic ultrasonography and found a 1 cm low echo nodule in the muscularis mucosa; the submucosal was thinner than normal but still continuous; mucosal hyperemia and erosion were found on the surface of the tumor. Endoscopic submucosal dissection (ESD) was performed and the histopathological finding showed a small cell carcinoma invading the submucosal layer. CONCLUSION: Early esophageal small cell carcinoma shows submucosal infiltrating growth with a hypoechoic mass in the muscularis mucosa as diagnosed by endoscopic ultrasonography. It is easily misdiagnosed as submucosal masses. Endoscopic manifestations should be identified and pathological biopsies should be employed. ESD may be performed to provide an opportunity for early treatment of PESCC.