Fig. 1Overall findings of the left ovary demonstrate a unilocular cyst filled with keratin-like material. A luminally-protruding (arrow head) and outer, expanding mass measuring 6.0 cm is noted. The cut surface of the mass is relatively grayish-white and firm in the luminal portion and was tan-colored and friable with hemorrhagic necrosis in the outer, expanding region.
Fig. 2Microscopically, the luminally-protruding portion exhibits a nodular arrangement of germinative cells with a pushing border that is abruptly connected to a stratified squamous epithelium of a mature cystic teratoma. Beneath the nodular portion, sheets or nests of infiltrating atypical cells are noted.
Fig. 3(A) Infiltrating cells arranged in trabeculae or nests that are focally contiguous to the inner, nodular portion with similar cytologic features. (B) Infiltrating cells show conspicuous vacuoles in the cytoplasm along with remarkable nuclear pleomorphism, prominent nucleoli, and frequent abnormal mitoses.
Fig. 4Cytoplasm of tumor cells reveals immunohistochemically-positive reaction for cytokeratin 7 (A), epithelial membrane antigen (B), carcinoembryonic antigen (C), and nuclear positive reaction for p63 (D).