Pancreatic mucinous cystic neoplasm

Pancreatic mucinous cystic neoplasm
Classification and external resources
Micrograph of a benign pancreatic mucinous cystic neoplasm. H&E stain.

Pancreatic mucinous cystic neoplasm, also mucinous cystic neoplasm of the pancreas and mucinous cystic tumour, is a grouping of cystic neoplasms that arise from the pancreas. They may be benign, malignant or in between.

The prognosis of this set of tumours is highly variable and dependent on the specific sub-classification (benign, borderline, malignant).

Definition

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 (or support structure).

Classification

Mucinous cystic neoplasms of the pancreas classified as benign, borderline, or malignant, based on histomorphologic features which predict their behaviour.^[1]

Symptoms

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. A multidisciplinary approach including good clinical history, state of the art imaging, and careful pathology is often needed to establish the correct diagnosis ^[2].

Pathology

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 (see the photograph). 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. ^[3].

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.

Treatment

A multi-disciplinary team approach, involving the coordinated efforts of clinicians, radiologists and pathologists is often the best way to evaluate a tumor involving the pancreas ^[2]. In general, if the patient is healthy enough, the treatment of choice is surgical resection. Patients with an invasive cancer arising in association with a mucinous cystic neoplasm are often treated post-operatively with chemotherapy or radiation therapy.

See also

• Solid pseudopapillary neoplasm
• Pancreatic serous cystadenoma
• Intraductal papillary mucinous neoplasm

References

1. ^ Theruvath TP, Morgan KA, Adams DB (August 2010). "Mucinous cystic neoplasms of the pancreas: how much preoperative evaluation is needed?". Am Surg 76 (8): 812–7. PMID 20726409. 
2. ^ ^{a b} "Pancreatic Cancer Multi-Disciplinary Clinic at Johns Hopkins University". http://pathology.jhu.edu/pancreas/MDC/index.php. 
3. ^ "Pancreatic Cancer Frequently Asked Questions". http://pathology.jhu.edu/pancreas/BasicTypes2.php.