An82-year-oldfemalepatientwithahistoryofprimarybiliarycholangitiswasdiagnosedwithtransversecoloncancerandunderwentlaparoscopiclefthemicolectomy.Oneyearlater,imageinspectionsde-tectedtumorswithadiameterofabout15and10mminsegment3oftheliver.Thepreoperativediagnosis was metachronous metastasis to the liver from transverse colon cancer. S3 subsegmentectomy was then performed. Histopathological findings revealed primary malignant lymphoma of the liver (diffuse large B-cell type). The postoperative course was uneventful, and she was discharged on postoperative day fourteen. R-CVP therapy as postoperative adjuvant chemotherapy was administered in 4 courses, andtherehasbeennoindicationofrecurrence18monthsafterthesurgery. Althoughprimarymalignantlymphomaoftheliverisdifficulttodiagnose,intheabsenceofextrahepaticlesions,liverresectionservesbothasadiagnosticmethodandthetreatment.Itisreportedthatthe originofthediseaseisrelatedtochronicliverdisease,autoimmunediseases,andsoon.Therearemany unclearissuesregardingitsonset,mechanism,andhistopathologicalcharacteristics. Therefore,furtherstudiesareneededtoestablishaconsensus.