Purpose of investigation: An endometrioid carcinoma coexisting with choriocarcinomatous differentiation is an uncommon event with an aggressive clinical course and a poor prognosis.
Materials and methods: The authors describe an endometrioid carcinoma of the endometrium provided with a focus of choriocarcinoma-like cells in a 50-year-old menstruated woman with a history of abnormal uterine bleeding. A total bilateral hystero-annessectomy was performed.
Results: Histopathologic study showed endometrioid adenocarcinoma limited to the endometrium with a single microinvasive (< one mm) choriocarcinomatous focus. Immunohistochemistry established intense reactivity of tumor cells for CK 7 and AE1/AE3, for beta-human chorionic gonadotropin (beta-hCG), and for HER2 confirming the diagnosis. During the clinical course and follow-up, serum levels of beta-hCG were always negative. Up to date the patient is still alive with no evidence of disease.
Conclusion: Even if endometrioid carcinoma with choriocarcinomatous differentiation is considered highly malignant, occasionally it may have a good prognosis, especially when a non-invasive behaviour is detected together with negative serum beta-hCG levels.