An 85-year old female had a polypoid tumour in the sigmoid colon that histologically conformed to a lymphoepithelioma-like (LEL) carcinoma. The tumour was arranged in cords, chains, clusters and microalveoli of pleomorphic, irregular cells set within a dense intratumoral lymphocytic stroma. The tumour was EBV-negative and showed loss of MLH-1 and PMS-2 mismatch repair proteins. The patient did not fulfil the criteria for HNPCC. Only 5 other cases of primary colonic LEL carcinoma have been described previously and only one case appears to have an unequivocal association with EBV. In addition, one of the cases was encountered in a HNPCC patient. This is an unusual morphologic variant of a microsatellite unstable tumour with a LEL pattern, not associated with EBV.
Keywords: EBV; Lymphoepithelioma-like carcinoma; intratumoral lymphocytes; medullary carcinoma; microsatellite instability; mismatch repair proteins.