Clinicopathological study on cystadenocarcinoma of the pancreas.

Although rare, mucinous cystadenocarcinoma of the pancreas is an established pathological entity. However, its characteristic features on diagnostic imaging have not yet been defined. Based upon clinicopathological studies on 5 cases, two subgroups of mucinous cystadenocarcinoma of the pancreas are proposed: the endophytic and the exophytic types. The former consist of large well-demarcated cystic tumors with numerous inward-growing cauliflower-like excrescences in mucinous material, which were characteristically demonstrated either by CT or ultrasonography. Tumors of this subtype were visualized as hypervascular masses in the capillary phase of angiography. Areas of malignant tissue were well-demarcated without capsular invasion, and tumors were free from lymph node or distant metastasis. Though cystic, the exophytic subtype had negligible inward-growing papillary projections. Corresponding to their macroscopic features, these tumors were demonstrated as cystic lesions lacking papillary projections on ultrasonography or CT. No tumor stains could be demonstrated by angiography. Despite of their smaller size than the former subtype, cancerous growth penetrated through the cyst wall and metastasized to lymph nodes, causing poorer prognosis than in the former.