Mucinous appendiceal neoplasms

FIGURE 14.16 Appendiceal mucinous neoplasm, low-grade, noninvasive. At higher magnification, the neoplastic cells are morphologically similar to those comprising so-called ovarian-primary mucinous borderline neoplasms. 

Appendiceal mucinous neoplasms can be distinguished from colonic mucinous adenocarcinomas by their comparatively greater CK7 staining and MUC5A reactivity, whereas colonic neoplasms tend to be nonreactive. 

FIGURE 14.17 Most appendiceal-primary mucinous neoplasms are CK20 positive (left) and either negative or focally reactive with CK7 (right). 

FIGURE 14.18 CDX2 is typically strongly reactive in the cell nuclei of appendiceal mucinous neoplasms. 

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