Duct ectasia due to mucus-producing cancers with intraductal extension: histopathologic correlation with radiologic imagings.

BACKGROUND: Although duct ectasia due to mucus-producing pancreatic cancer has been well known, its occurrence in other organs has not been reported. We have studied the pathologic basis of the radiologic features in cases of mucus-producing cancer with intraductal extension.
METHODS: We conducted a comparative study of detailed various radiographic images and pathological findings in 10 cases of mucus-producing cancers (four of mucus-producing pancreatic cancer, two of mucinous gastric cancer with diffuse lymphangitic liver metastasis, and four cases of bronchoalveolar cell carcinoma with cyst or cavity).
RESULTS: When mucus-producing cancer occurs in a secretory duct or extends into lymphatic ducts, the normal duct is dilated due to the mucus and increased internal pressure, leading to the formation of a cyst and cavity. Because of having the liquid property of mucus floating cancer cells, the lesion can easily progress to continuous ducts as well as regionally.
CONCLUSIONS: In cases of mucus-producing cancer with extension into the ductal structure not only in the pancreas but also in the lung and liver, continuous duct ectasis and cysts filled with mucus or cavities of all sizes made by the nature of the mucus may be detected by CT and US.