Abstract
Background : Ovarian ependymoma is a rare neoplasm that resembles ependymoma of the central nervous system (CNS). We examined the matching features between the imprint cytological findings and histological findings of ovarian ependymoma, and the histological features of ovarian ependymoma.
Case : A 23-year-old woman underwent laparoscopic resection for a cystic lesion of the right ovary. The unilocular cyst included a nodule. We prepared imprint cytologic specimens from the nodule. Cytologically, discohesive irregular cell clusters with focal rosette formation and fibrillar cytoplasmic processes and cells arranged in sheets were observed. The cytoplasmic processes were immunocytochemically positive for GFAP. Histologically, we recognized perivascular pseudorosette formation, ependymal rosette formation, and clear cell proliferation. Immunohistochemically, the tumor was positive for GFAP. Based on the findings, we diagnosed this tumor as ovarian ependymoma.
Conclusion : Our findings suggest that the origin of the tumor and mechanism of tumor development differ between ovarian ependymoma and CNS ependymoma, because the histological and immunohistochemical findings appeared to differ between the two. An accurate diagnosis may be made rapidly based on the age of the patient, the characteristic macroscopic and cytologic findings, and the GFAP immunopositivity.
