The diagnosis of primary neoplasm of the gallbladder is a clinical problem the preoperative solution of which may be dependent on a thorough roentgenologic study. Because of the importance of this method of examination, a review of available roentgenograms has been undertaken in a search for possible distinctive and diagnostic characteristics. Films were available in 33 cases seen at the Massachusetts General Hospital in which primary cancer of the gallbladder had been histologically proved. Cases in which the tumor was of undetermined origin were excluded. Carcinoma of the gallbladder is not a common disease, the postmortem incidence being approximately 0.4 per cent (6). At this hospital, over the period covered by the present study, carcinoma of the pancreas was diagnosed four times more frequently than carcinoma of the gallbladder. The gross pathological picture of carcinoma of the gallbladder is conditioned by the anatomy of the organ and of the lymphatic drainage (2, 4). The gallbladder is a subserosal sac which lies along the inferior margin of the liver. Its posterior limit, as it joins the cystic duct, is closely related to the superior and lateral aspects of the upper flexure of the duodenal loop. Its anterior limit, the fundus, frequently is at the anterior margin of the liver, and may extend beyond this to be in contact with the anterior abdominal wall. The gallbladder generally lies lateral to the pyloric antrum and medial to the hepatic flexure. Its position, however, is quite variable, depending on such factors as the level and inclination of the inferior surface of the liver and the presence or absence of a gallbladder mesentery. The lymphatics of the inferior surface of the liver drain toward the lymph nodes of the porta hepatis, and the lymphatics of the gallbladder join these. Portal nodes also receive lymphatics from the peripancreatic and mesenteric regions. In addition there is a rich lymphatic and venous anastomosis between the gallbladder and the adjacent liver parenchyma. The histology of primary cancer of the gallbladder has been reviewed amply in the literature (11). The tumor is usually an adenocarcinoma but occasionally is of the squamous variety; sarcomas have been reported. Whatever the type, it is commonly associated with cholelithiasis, and almost invariably with cholecystitis. The carcinoma may form a bulky mass within or around the gallbladder, or it may provoke a scirrhous reaction resulting in a small fibrosed and contracted gallbladder. Direct spread to the liver occurs early. Local metastases to the porta hepatis and liver are frequent, and metastatic involvement of peripancreatic and mesenteric lymph nodes is not unusual. Peritoneal dissemination occurs occasionally, but distant metastases in lung or bone are uncommon. Carcinoma metastasizing to the gallbladder is extremely rare, except as part of a general peritoneal carcinomatosis. In the present series there were 28 adenocarcinomas and undifferentiated carcinomas, 3 squamous-cell carcinomas, 1 adenoacanthoma, and 1 sarcoma. The clinical picture associated with cholecystic cancer is well established (2, 6, 11). The patient is generally a female with moderately acute symptoms (the most common being upper abdominal pain and jaundice) of short duration. Occasionally these have been superimposed on chronic biliary symptoms of much longer duration. In the group presented, 28 of the 33 patients were women. The average age at admission to the hospital was sixty-six years; the youngest patient was forty-eight. The average duration of symptoms was less than six months. Twenty-seven of the 33 patients complained of pain, and in 18 there was jaundice, which was usually the immediate cause for seeking medical advice. Unusual presenting symptoms were the feeling of a mass, vomiting, ulceration of a cholecystostomy scar, and fever.