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WHO Classification of Tumours
Intraductal tubulopapillary neoplasm (ITPN)


The immunohistochemical labelling profile of intraductal papillary neoplasms (ITPNs) confirms their ductal nature. The neoplastic cells commonly label for keratins 7 and 19, in addition to displaying consistent positivity for pankeratins. Labelling for the acinar marker, trypsin, and endocrine markers chromogranin and synaptophysin, is negative. Mucinrelated glycoproteins are typically expressed at lower levels than in mucinous ductal neoplasms: CA19-9 is commonly detected but only as a focal finding. B72.3, CEA and CA125/MUC16 are detected in less than half of cases and typically as a very focal finding. Neither MUC5AC, which is a consistent marker of intraductal papillary mucinous neoplasms (IPMNs) regardless of type, nor MUC2, which is expressed in intestinal-type IPMNs, are expressed in ITPNs. MUC1 is expressed in 90% and MUC6 in 60% of ITPNs. The expression of SMAD4/DPC4 is retained in most cases. Immunohistochemical expression of p53 and CDKN2A/p16 are detected in 20% and 54% of cases, respectively. The Ki67 labelling index varies from case to case (range, 643%). β-Catenin nuclear expression and loss of E-cadherin expression are reported in < 10% of ITPNs
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Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
4th Edition
International Agency for Research on Cancer: Lyon 2010


Table: Differential immunolabelling of intraductal neoplasms of the exocrine pancreas
Histopathological type MUC1 MUC2 MUC5AC MUC6 CDX2
IPMN Intestinal - ++ ++ - ++
Pancreatobiliary ++ - ++ + -
Gastric - - ++ - -
Oncocytic + - + ++ -
ITPN + - - ++ -
IPMN, intraductal papillary mucinous neoplasm; ITPN, intraductal tubulopapillary neoplasm.
no labelling; +, may be positive; ++, usually positive

Diagnostic algorithms for tumours of the pancreas