Carcinoma is the most common tumor of the pancreas. Its incidence has been cited as from 1.76 to 2 per cent in cases of cancer in which autopsy was done.1 The types of carcinoma vary considerably in histologic appearance and manner of growth. Three main categories are recognized as representing duct, acinar and "islet" structures.2 Rarer types, such as mucoid, colloid or squamous (duct) forms, were not seen in this series. As with cancer situated elsewhere, the causes are unknown. In view of the complex origin of the mature pancreas, which involves anatomic and functional fusion of two separate (dorsal and ventral) duct systems (Wirsung and Santorini), the possibility of developmental errors may be of some importance. This supposition is further supported by the frequency with which carcinoma occurs in the head of the pancreas and the preponderance of the duct type. To this evidence must be added