Immunohistochemical characterization of appendiceal mucinous neoplasms and the value of special <scp>AT</scp>‐rich sequence‐binding protein 2 in their distinction from primary ovarian mucinous tumours

SATB2 is frequently expressed in appendiceal mucinous neoplasms. In the context of a mucinous neoplasm involving the ovary, any SATB2 positivity should raise the possibility of appendiceal origin. Expression of CK20, CDX2 and MUC2 supports appendiceal origin only when diffuse and strong. These and other markers, such as CK7 and PAX8, are recommended in the work-up of ovarian mucinous tumours with any clinical or pathological features suggestive of secondary origin.