Figure 1:

Mixed gastrointestinal-type mucinous / Mullerian cystadenomas. (A-C) Cy-1, (A) low-magnification image showing the spatial relationship of Mullerian and mucinous components; (B) High magnification of boxed area in (A), illustrating cuboidal/columnar cells with cilia; (C) another area showing gastric foveolar differentiation, with diffuse MUC6 expression (inset, left) and neutral mucin, staining magenta by AB/PAS histochemistry (inset, right). (D-F) Cy-3; (D) Cystic structure (right) lined by attenuated simple epithelium and an overlying stretch of columnar epithelium with Paneth-like cells at the surface. These foci show differential expression of (E) PAX8, and (F) CDX2, indicative of Mullerian and gastrointestinal differentiation, respectively. (G-K) Cy-4; (G) Within this cystadenoma, there are intestinal-type glands containing goblet cells and scattered neuroendocrine cells. The intestinal-type glandular epithelium is positive for (H) PAX8, (I) CDX2, and (J) CK20 (focal). (K) Other areas show mucinous glands exhibiting a hybrid gastric/endocervical phenotype, containing cells producing neutral and acidic mucin, staining magenta and blue, respectively, by AB/PAS histochemistry.