PMC5192324_01
Low power photomicrograph showing a cystic mass with infoldings and excrescences of its wall at the inner aspect. The cyst lining is easily appreciated. H&E. Magnification, 40x.
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fig1
On low magnification, sections showed a cystic lesion whose fibrocollagenous wall was thrown into multiple folds forming finger-like projections focally (Figure 1).
Higher magnification reveals that the cyst is lined by a ciliated simple columnar epithelium reminiscent of that of Mullerian derived structures. H&E. Magnification, 400x. The inset highlights occasional cells with round nuclei and perinuclear clearing at the base of the epithelium (green arrows). These cells are similar to those seen in fallopian tube epithelium. H&E. Magnification, 600x.
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fig2
High magnification revealed a cyst lining formed by a simple ciliated cuboidal to columnar epithelium with no significant cytologic atypia (Figure 2). Occasional cells with round nuclei and perinuclear clearing seen towards the base of the epithelium were reminiscent of cells seen in fallopian tube epithelium (Figure 2, inset).
The immunohistochemical staining profile supports the notion of a Mullerian origin. Progesterone receptor immunostain shows strong and diffuse positivity in the cyst lining epithelium ((a) magnification, 100x) and PAX-8 is positive in the majority of the epithelial lining cells ((b) magnification, 200x). The lining is strongly and diffusely positive for WT1 immunostain which is localized to the nuclei ((c) magnification, 100x).
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fig3
By immunohistochemistry, the epithelial cells were positive for pan-cytokeratin (AE1/AE3), estrogen receptor (ER), progesterone receptor (PR), PAX-8, and WT1 (Figures 3(a), 3(b), and 3(c)).