Primary endometrioid adenocarcinoma of the cervix with widespread squamous metaplasia – a potential diagnostic pitfall

BACKGROUND Uterine or endocervical biopsies that contain endometrioid adenocarcinoma with widespread squamous metaplasia are usually of endometrial origin. The presence of squamous metaplasia is said to be helpful in distinguishing endocervical from endometrial adenocarcinomas in small biopsy samples. CASE PRESENTATION A 51-year-old woman presented with post-coital and post-menopausal bleeding. Biopsy of a friable lesion in the proximal endocervical canal revealed an endocervical adenocarcinoma of endometrioid type with widespread squamous metaplasia. The latter feature initially raised the possible diagnosis of a primary endometrial adenocarcinoma. However, immunohistochemical marker studies indicated a diagnosis of primary endocervical adenocarcinoma of endometrioid type and this was confirmed at hysterectomy. CONCLUSION Squamous differentiation is not well documented in endocervical adenocarcinomas of endometrioid type and, when widespread, may represent a diagnostic pitfall for pathologists. Interpretation of small biopsies from the endocervical canal on the basis of morphology alone may lead to misdiagnosis and inappropriate surgical management.