Carcinoma cuniculatum of the esophagus

AIMS: Extremely well-differentiated squamous cell carcinoma with the features of so-called carcinoma cuniculatum (CC) is a rare neoplasm. We describe the clinicopathologic findings of the first 2 cases of CC of the esophagus. METHODS AND RESULTS: Two elderly men presented with symptoms and clinical signs of esophageal malignancy. Repeated endoscopic biopsies of their esophageal tumors were inconclusive. Resection revealed CC of the esophagogastric junction in both cases. The tumors extended into the adventitia but no lymph node metastases were present. In situ hybridization for human papillomavirus HPV subtypes was negative. CONCLUSION: Carcinoma cuniculatum is reported for the first time in the esophagus. The diagnosis of this tumor variant is difficult by means of cytological examination or by endoscopic biopsies alone. Carcinoma cuniculatum in this location shows biologic features similar to verrucous carcinoma (deep penetration, no lymph nodes metastases, and location at one end of the esophagus). No evidence of human papillomavirus could be demonstrated.