Fig. 1

Case 1. (A1) Sagittal contrast-enhanced T1-weighted MRI shows heterogeneously enhanced mass filling the endometrial cavity with cervical stromal invasion. (A2) The tumor shows white infiltrative lesion with necrosis involving lower uterine segment and uterine body, extending to cervix. The UC component (A3, ×2.5) infiltrates the full thickness of the lower uterine segment and arranged in patternless with extensive necrosis and hemorrhage. The tumor (A4, ×400) comprises monotonous cells with moderate pleomorphism, prominent nucleoli, and high mitotic rates. Cytokeratin 8/18 (CK8/18) expressed as perinuclear dots in the UC component (A5, ×400) and showed diffuse cytoplasmic expression in differentiated component (A6, ×200)