Mixed High-Risk Endometrial Carcinoma Initially Presented With Atypical Squamous Cells of Undetermined Significance (ASC-US) Cytology: Lessons to Be Learned.

Endometrial carcinoma represents the most common gynecologic malignancy, affecting mainly postmenopausal women. Early detection and proper management may allow not only a successful treatment but also an acceptable quality of life. Although its usual clinical manifestations, such as vaginal bleeding or a mass stuck out of the cervix, often arouse medical concern, in some cases, there is a dilemma regarding the differential diagnosis of endocervical cancer. Additionally, tumors arising from and confined to the uterine isthmus may often pose a greater diagnostic challenge. Defining the primary origin of the carcinoma is of paramount importance as the treatment plan may be widely different in these two scenarios. Magnetic Resonance Imaging (MRI), markers, and biopsy with immunohistochemistry could facilitate the diagnostic process, but the final diagnosis may even be made from the final surgical specimen in such demanding cases. We present the case of a mixed-type, stage IIIC2, endometrial carcinoma arising from the lower uterine segment initially suspected from atypical squamous cells of undetermined significance (ASC-US) cytology.