A Case of Esophageal Squamous Cell Carcinoma in situ Arising from Esophageal Squamous Papilloma.

Squamous papilloma is a common benign tumor of the esophagus. Patients with papilloma are usually asymptomatic, and they are diagnosed incidentally during esophagogastroduodenoscopy. Most papillomas are small and easily removed by forceps biopsy. Recurrence of papilloma after removal is rare. Human papilloma virus infection is supposed to play a role in the development of esophageal papilloma; however, malignant transformation of papilloma is extremely unusual. Here, we report a case of malignant transformation of esophageal squamous papilloma at the gastroesophageal junction into squamous cell carcinoma in situ, which was treated by endoscopic submucosal dissection.