Primary hepatic lymphoma is an extremely rare malignancy accounting for 0.016% of all cases of non-Hodgkin lymphomas. Approximately 1-4% of histologies described show a follicular pattern. We report a case of primary hepatic non-Hodgkin lymphoma that developed in a middle-aged woman 3 years after radical treatment (neoadjuvant chemoradiotherapy and surgery) for a rectal adenocarcinoma. Abdomen ultrasound showed a single nodule in the liver, which raised the issue of differential diagnosis with a metastasis from rectal cancer. After surgical removal of the nodule, histology revealed a primary B cell, stage IE follicular non-Hodgkin lymphoma, confined to the liver; indeed, no foci of lymphoma were found elsewhere in the body.