PANCREATIC METASTASES - CT ASSESSMENT

We report the CT appearance of pancreatic metastases and describe thei r features in relation to the originating primary tumor. We also discu ss some limitations in their differential diagnosis and report some th eories explaining the pathogenesis of their occurrence. A total of 20 cases (9 males and 11 females) of pancreatic metastases were diagnosed at staging or follow-up of oncologic patients. All patients were eval uated with CT before and after contrast medium administration and had subsequent pathologic confirmation. In 1 case metastases were located solely in the pancreas; in 6 there was only another metastatic locatio n, and in the remaining 13 there was diffuse spread throughout the bod y. Two of our patients exhibited a multinodular metastatic involvement of the pancreas, 11 had a solitary nodule or mass, and the remaining 7 had a diffusely enlarged pancreas, without any signs of focal diseas e. All but one of the solitary lesions measured more than 4 cm. In 2 c ases a metachronous malignancy was detected at follow-up. Primary mali gnancies were located: 6 in the lungs, 2 on the skin (melanomas), 3 in breasts, 2 in the ovaries, 3 in the colon, 1 in the stomach, 2 in the kidney, and 1 the thyroid. Our findings confirm the existence of thre e patterns of metastatization to the pancreas: large solitary masses, multinodular lesions, and diffuse enlargement of the pancreas without focal signs at CT. In contrast to other studies, the large solitary le sion was our most frequent encounter, therefore making differential di agnosis vs primary cancer difficult. Metastases tended to repeat the i maging pattern of the primary. Nevertheless, we wrongly diagnosed panc reatitis due to a small nondetected metastasis, pseudo-cystic mass as a mucinous cystadenocarcinoma, conglomerate of peripancreatic lymph no des, and a solitary pancreatic mass diagnosed as primary pancreatic ca ncer. Thus, when faced with a solitary pancreatic lesion at follow-up, histologic diagnosis is strongly recommended. In 2 cases changes in a spect and size were related to therapy.