Unmasking Mixed Endometrial Carcinoma: A Case Report of Diagnostic Complexity

Mixed endometrial carcinoma (MEC) is a rare entity, representing only a small fraction of endometrial cancers. It is characterized by the presence of two or more distinct histological patterns, with at least one being a high-grade type such as serous or clear cell carcinoma. We present a 61-year-old postmenopausal woman who presented with abnormal uterine bleeding, intermittent lower abdominal pain, and mild pelvic discomfort for 2 months. Ultrasound revealed a thickened, irregular endometrium with a heterogeneous mass. Endometrial biopsy and immunohistochemistry confirmed the presence of mixed endometrial carcinoma. Subsequently, the patient underwent hysterectomy, and on gross, the endometrial cavity was showing a friable, irregular growth with papillary excrescences infiltrating into the myometrium. On microscopy, the coexistence of endometrioid and serous components was established, confirming the diagnosis.