Fig. 3

Histopathological and immunohistochemical findings of cystic lesions of the tumor. a Cystic and dilated endometrial glands are present in the extrauterine component, with degenerated blood inside (hematoxylin-eosin staining; object lens magnification, ×1.25). b The cyst is lined by one layer of columnar cells that resemble endometrial epithelium without cellular atypia and is surrounded by stromal cells (hematoxylin-eosin staining; object lens magnification, ×40). c The stromal cells are positive for CD10, an endometrial stromal marker (immunohistochemistry; object lens magnification, ×10). d Lesions of cotyledonoid dissecting leiomyoma (yellow) and adenomyosis (red) are mapped in the gross specimen shown in Fig. 1c , based on microscopic examination. Adenomyosis lesions are located not only in the extrauterine component but also in the intrauterine tumor lesion and thickened tumor-free myometrium