In a consecutive series of 317 patients with hepatocellular carcinoma (HCC), 32 (10.1%) had 35 extrahepatic primary malignant neoplasms (PMNs) (3 patients had triple cancers). Twenty-five PMNs occurred before the diagnosis of HCC, 7 were synchronous and 3 metachronous. These 35 PMNs were: 6 cancers of the colon, 3 of the stomach, 1 of the rectum, 4 of the breast, 2 of the lung, 1 of the larynx, 3 of the prostate, 1 of the penis, 1 of the urinary bladder, 1 of the uterus, 2 of the skin, and the remaining 10 were immunoproliferative cancers, all of B cell origin (7 non-Hodgkin’s lymphoma, 2 multiple myeloma, and 1 chronic lymphocytic leukemia). Thus, in this series, B-lymphocyte-derived neoplasms were the most frequent PMNs associated with HCC. These 10 patients showed no difference for age, male:female ratio, HCC cytotype, presence of cirrhosis, alcohol abuse, markers related to hepatitis B and C virus, and serum level of a-fetoprotein when compared with the 22 patients with HCC and other PMNs and the 285 with HCC alone. B cell neoplasms constitute half of the synchronous or metachronous cancers, and must, therefore, be kept in mind in the management of HCC patient