Enlarging Inflammatory Granulation Tissue After Endoscopic Submucosal Dissection at the Esophageal Inlet During Intensive Stricture Prophylaxis: A Case Report

Surveillance endoscopy in a 47-year-old woman with previous hypopharyngeal chemoradiotherapy and esophageal endoscopic submucosal dissection (ESD) revealed a 12-mm superficial squamous cell carcinoma at the cervical esophagus near the inlet. ESD achieved en bloc resection with a half-circumferential mucosal defect, and histopathology showed pT1a lamina propria mucosae with negative margins. For stricture prophylaxis, triamcinolone was injected into the post-ESD defect, oral prednisolone was tapered over several months, and prophylactic endoscopic balloon dilation was performed three times at 3-4-week intervals. Three months after ESD, a 10-mm white-coated lesion appeared at the inlet and progressively enlarged. Under intravenous sedation, detailed endoscopic assessments and biopsies were limited by the complex location, and the biopsy suggested neoplastic cells with marked degeneration. Due to progressive odynophagia and poor oral intake, endoscopic re-evaluation under general anesthesia was performed. Using Sato's curved laryngoscope, the lesion was clearly visualized as a semipedunculated mass arising from the post-ESD site and was completely resected for diagnosis and symptom relief. Histopathology revealed inflammatory granulation tissue without malignancy. Symptoms resolved promptly with no recurrence during 6 months of follow-up. This case highlights the development of exuberant granulation tissue at the post-ESD site in the cervical esophagus during intensive stricture prophylaxis. Although this rare finding likely reflects multiple overlapping factors, endoscopic evaluation and treatment were successfully performed while avoiding overtreatment.