Figure 3

Microscopic photograph of the tumor. A. Cystic structure is lined by benign columnar mucinous epithelial cells (arrow). Subepithelial stroma is composed of bland looking spindle cells (asterisk) mimicking ovarian stroma (hematoxylin and eosin, × 200). B. Stromal cells are immunoreactive against calretinin (× 200). C. Stromal cells are reactive against progesterone receptor (× 400). D. Columnar epithelia are accompanied by intestinal metaplasia with scattered goblet cells (right) as well as pseudopyloric metaplasia (left) (hematoxylin and eosin, × 200). E. Scattered endocrine cells (arrows) are highlighted by reactivity to chromogranin A (× 400). F. Cysts are lined by benign transitional-type epithelium, beneath which the stroma is hyalinized (hematoxylin and eosin, × 200). G. Transitional cells are immunoreactive to high molecular weight cytokeratin (× 400).