6 August 2009 - Case #154

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This case was contributed by Dr. Renuka Agrawal, Loma Linda University Medical Center, California (USA).


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Case #154

Clinical history:
An 81 year old woman presented with epigastric pain caused by pancreatitis. CT scan showed a cystic papillary tumor in the head of the pancreas and a dilated pancreatic duct. The duodenum, pancreas and spleen were resected.

Gross image:


Microscopic images:

H&E sections

MUC1, MUC2 and MUC5AC




What is your diagnosis?

Click here for diagnosis and discussion:


Diagnosis: Intraductal papillary mucinous neoplasm (IPMN), intestinal type

Discussion:
Intraductal papillary mucinous neoplasms (IPMNs) are cystic, mucin producing neoplasms of the pancreas. They are grossly visible, papillary epithelial neoplasms which arise from the main pancreatic duct or branch ducts, with mucin extrusion from the ampulla and varying degrees of duct dilation. They display complex papillary fronds of mucin producing epithelial cells and are associated with chronic pancreatitis. There is no ovarian type stroma.

IPMNs are more common in men over age 60. They typically occur in the head of the pancreas.

4 histologic subtypes are recognized: gastric, intestinal, pancreaticobiliary and oncocytic. They also have a spectrum of atypia ranging from adenoma to invasive cancer (Virchows 2005;447:794). The biological behavior of invasive cancers arising from IPMNs is better than that of de novo pancreatic adenocarcinoma. The surgical pathology report on IPMNs should indicate whether the main or branch ducts are involved, the presence and extent of invasion and margin status.

A MUC1 / MUC2 expression profile may be helpful (Mod Pathol 2002;15:1087). MUC1 is an indicator of aggressive pancreatic neoplasms, while MUC2 is a marker of indolent phenotypes (J Clin Pathol 2004;57:456). In intestinal IPMN, MUC2 and MUC5AC are positive and MUC1 is negative. This subtype usually involves the main pancreatic duct, has a more favorable prognosis, and is not associated with ductal carcinoma (Am J Surg Pathol 2006;30:1561, Am J Surg Pathol 2001;25:942). However, intestinal type IPMN can be invasive and at these times, is associated with colloid carcinoma (Am J Surg Pathol 2004;28:839). Prognosis can be unpredictable and depends on the severity of invasion.

Resection is adequate treatment for adenomas, which do not recur (Ann Surg Oncol 2006;13:582). Invasive tumors may be lethal and require chemotherapy or radiation (Int J Radiat Oncol Biol Phys 2010;76:839, Ann Surg Oncol 2007;14:3174). Minimally invasive tumors have similar survival rates as noninvasive tumors (Am J Surg Pathol 2008;32:243).

The differential diagnosis includes:


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