Intestinal-Type Adenocarcinoma: Classification, Immunophenotype, Molecular Features and Differential Diagnosis

Ilmo Leivo

doi:10.1007/s12105-017-0800-7

Abstract

Intestinal-type adenocarcinoma is the second most frequent sinonasal adenocarcinoma. High incidence of these tumors is seen among workers with occupational wood dust exposure, particularly of hardwood dusts. Intestinal-type adenocarcinoma has striking histomorphologic and immunophenotypic similarities with colorectal adenocarcinomas, but on the level of molecular pathologic mechanisms these tumors have their own specific features different from gastrointestinal tumors. This article provides an update on current histopathologic classification of intestinal-type adenocarcinomas, their immunophenotypic properties, recent advances in molecular pathologic features and differential diagnostic considerations.

Highlights

Intestinal-type adenocarcinoma (ITAC) is the second most common type of sinonasal adenocarcinoma after adenoid cystic carcinoma. It is composed of subtypes described by Dr Barnes that resemble carcinomas or adenomas of intestinal origin, and occasionally the normal intestinal mucosa [1, 2]
Occupational wood dust exposure has been documented in ca. 20% of cases of ITAC, while the rest are sporadic
Papillary ITACs may recapitulate the morphology of the normal intestinal mucosa with nearly normal-looking villi including the specialized cell types and the muscularis mucosae [12]

Summary

Immunophenotype and Molecular Features

Immunohistochemical staining indicates that ITACs are positive for CK20 (Fig. 5a), CDX-2 (Fig. 5b), villin, and MUC2, and variably positive for CK7 (Fig. 5c) [14,15,16]. Occasional neuroendocrine cells in ITACs often express chromogranin A (Fig. 5d) and/or synaptophysin. High levels of EGFR protein expression has been found in a subset of ITACs, Fig. 5 Immunohistochemical staining of intestinal-type adenocar- ▸ cinoma, papillary subtype. The frequency of TP53 mutations in ITAC has ranged between 18–53% in different series [21, 26, 27]. The risk of such mutations increases with the duration and cumulative level of wood dust exposure [26, 27], but apparently not of smoking [27]. It has been speculated that mutations occurring during wood dust exposure might be related to reactive oxygen and/or nitrogen species generated by chronic inflammation [26, 27]

Differential Diagnosis

Findings

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