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

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.

Keywords: Head and neck adenocarcinoma; Immunohistochemistry; Intestinal-type adenocarcinoma; Molecular pathology; Sinonasal adenocarcinoma; Sinonasal nonintestinal adenocarcinoma; Wood dust exposure.

Fig. 1

a Intestinal-type adenocarcinoma, papillary subtype. The tumor has ample papillary projections, and some glandular and tubular areas. H–E stain ×250. b The cells are usually cylindrical with elongated and pleomorphic hyperchromatic nuclei and nuclear crowding. Several mitotic figures are seen. H–E stain ×400. c Intestinal-type adenocarcinoma, highly differentiated papillary subtype resembling normal intestinal mucosa. H–E stain ×150. d Note the orderly arrangement of cylindrical cells in the papillae with only mild nuclear atypia. Occasional mitotic figures are seen. H–E stain ×400

Fig. 2

a Intestinal-type adenocarcinoma, colonic subtype. The tumor has glandular and trabecular areas resembling appearances of colorectal adenocarcinoma. H–E stain ×250. b The nuclei are crowded and highly pleomorphic and show some hyperchromasia. There is high mitotic activity. H–E stain ×400

Fig. 3

Intestinal-type adenocarcinoma, solid subtype. The tumor displays a diffuse growth pattern with minor amounts of poorly differentiated glandular lumina. There is high mitotic activity. H–E stain ×250

Fig. 4

Intestinal-type adenocarcinoma, mucinous subtype. a Tumor cells form clusters with glandular lumina, b and strips with goblet-type cells, and are surrounded by ample pools of mucin. H–E stain ×400

Fig. 5

Immunohistochemical staining of intestinal-type adenocarcinoma, papillary subtype. a CK20 is seen in most tumor cells, b CDX-2 stains all tumor nuclei, c CK7 is variably positive in tumor cells, d chromogranin A is seen in occasional neuroendocrine cells. Peroxidase conjugated ABC Kit (Dako) ×400