Various
mucin-producing
neoplasms originate in different abdominal and pelvic organs.
Mucinous neoplasms differ from non-
mucinous neoplasms because of the differences in clinical outcome and imaging appearance.
Mucinous carcinoma, in which at least 50% of the
tumor is composed of large pools of extracellular
mucin and columns of malignant cells, is associated with a worse prognosis.
Signet ring cell carcinoma is characterized by large intracytoplasmic
mucin vacuoles that expand in the malignant cells with the nucleus displaced to the periphery. Its prognosis is also generally poor. In contrast, intraductal papillary
mucinous neoplasm of the bile duct and pancreas, which is characterized by proliferation of ductal epithelium and variable
mucin production, has a better prognosis than other
malignancies in the pancreaticobiliary tree. Imaging modalities play a critical role in differentiating mucinous from non-
mucinous neoplasms. Due to high water content,
mucin has a similar appearance to water on ultrasound (US), computed tomography (CT), and magnetic resonance imaging, except when thick and proteinaceous, and then it tends to be hypoechoic with fine internal echoes or have complex echogenicity on US, hyperdense on CT, and hyperintense on T1- and hypointense on T2-weighted images, compared to water. Therefore, knowledge of characteristic
mucin imaging features is helpful to diagnose various
mucin-producing neoplastic conditions and to facilitate appropriate treatment.