Mucinous Cystic Neoplasms of the Pancreas
A variety of tumors can arise in the pancreas. Not all of them are cancerous, and some, such as the mucinous cystic neoplasm, are curable if detected early enough. These entities are important to recognize because they are curable and treated very differently from the usual infiltrating adenocarcinoma of the pancreas.
Mucinous cystic neoplasms of the pancreas are defined by the World Health Organization (WHO) as cystic epithelial neoplasms that occur almost exclusively in women; do not communicate with the pancreatic ductal system and which are composed of columnar, mucin-producing epithelium, supported by ovarian-type stroma. This mouthful simply means that these tumors make mucin (a thick sticky fluid), they do not arise in the larger pancreatic ducts, and they have a peculiar supporting stroma.
Most mucinous cystic neoplasms arise in women (95%) and these women are usually in their 40s or 50s. Clinically many mucinous cystic neoplasms are discovered as incidental findings during imaging for another indication. Larger mucinous cystic neoplasms can compress adjacent organs and lead to weight loss, or a sense of fullness. Really large mucinous cystic neoplasms can even be felt on physical examination.
If the patient is healthy enough, the treatment of choice is surgical resection. Resected mucinous cystic neoplasms have a characteristic appearance- they tend to be between 6 and 10 centimeters in size (2 to 5 inches), they contain numerous cysts (small cavities), and the cysts are filled with thick mucin. Under the microscope, the cysts are line by tall mucin-producing cells. These are the tumor cells. The tumor cells “sit” on ovarian-type stroma. This “ovarian-type stroma” is connective tissue that resembles some of the tissue normally found in the female ovary.
Some mucinous cystic neoplasms are confined to the tumor. These are designated using various names including “mucinous cystic neoplasm with low-grade dysplasia,” “mucinous cystic neoplasm with moderate dysplasia,” “borderline mucinous cystic neoplasm,” and “mucinous cystic neoplasm with high-grade dysplasia.” These are all curable when completely removed surgically. About a third of mucinous cystic neoplasms have progressed or “degenerated” into an invasive cancer. These are designated either “mucinous cystadenocarcinoma” or “mucinous cystic neoplasm with an associated invasive carcinoma.” These latter lesions have the potential to spread (metastasize) to other organs. Patients with one of these tumors are often treated post-operatively with chemotherapy or radiation therapy.
Mucinous cystic neoplasms are often best managed by a multi-disciplinary team. To learn more about the Multi-Disciplinary Clinic at Johns Hopkins, click the link below.