PMC6370064_01
Microscopic appearance of ovarian tumor and greater omental lesion (hematoxylin-eosin staining). A: A mucinous cystadenoma is the main part of the epithelial elements (x100). B: The sarcomatous mural nodule consists of ovoid mononucleated cells and numerous multinucleated osteoclast-like giant cells (x100). C: Nine mitotic figures are observed in one high-power field in the mural nodule consisting of pleomorphic undifferentiated sarcoma (x400). D: Vascular invasion is observed in the lager mural nodule (x200). E: Benign Brenner tumor is composed of nests of transitional epithelium (x100). F: The greater omental lesion shows nodular histiocytic aggregates.
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F1
The cystic component was preponderant, and the cysts were lined largely by low columnar or cuboidal well-differentiated mucinous epithelium, indicating a benign tumor with focal borderline changes and intraepithelial carcinoma (Fig. 1A). The larger mural nodule underneath the mucinous epithelium consisted of ovoid mononucleated cells and numerous multinucleated osteoclast-like giant cells (Fig. 1B). Vascular invasion was also observed in this mural nodule (Fig. 1D). As the third component, the smaller nodule consisted of nests of transitional epithelium, which embedded in a dense fibromatous stroma (Fig. 1E). The greater omental lesions consisted of little nests or sheets of cohesive polygonal-to-oval epithelioid cells with distinct cell borders, abundant cytoplasm, and inconspicuous nucleoli (Fig. 1F).
Immunohistochemical features of mural nodule of pleomorphic undifferentiated sarcoma. Mononucleated and multinucleated cells are positive for vimentin (A, x200) and CD68 (B, x200). CD34 staining shows tumor cells infiltrating capillary vessels (C, x400).
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F2
The mononucleated and multinucleated cells in the sarcomatous mural nodule were positive for vimentin (Fig. 2A), cluster of differentiation (CD)56, CD68 (Fig. 2B), and human alpha1 antichymotrypsin, but negative for pan-cytokeratin (CK), CK7, CK20, desmin, alpha-smooth muscle actin, calretinin, CD10, and P63. S-100 protein. Staining with CD34 revealed intravascular tumor emboli and vascular invasion (Fig. 2C).
Immunohistochemical features of nodular histiocytic aggregates in the greater omentum (x200). The mononuclear cells on the surface of the greater omentum show diffuse and strong reactivity against vimentin (A), CD68 (B), and scattered positivity for calretinin (C).
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F3
The mononuclear cells on the surface of the greater omentum showed diffuse and strong reactivity against vimentin (Fig. 3A) and CD68 (Fig. 3B). There were a few scattered mesothelial cells among the mononuclear cells that stained positive for calretinin (Fig. 3C) and CK5/6.