Adenomatoid tumor of the uterus: analysis of misdiagnosed cases and a literature review.

Adenomatoid tumors are rare, specific, benign tumors of the reproductive tract that originate from mesenchymal tissue. A patient was diagnosed with uterine fibroids 1 year previously when a mass of approximately 30 mm was found in the left adnexal region during a physical examination. At 1 year of follow-up, ultrasound showed that the mass in the left adnexal area had greatly increased to 61 × 45 × 50 mm. Contrast-enhanced pelvic magnetic resonance imaging (MRI) was performed before surgery and suggested a borderline tumor. Histopathology suggested signet ring cell carcinoma, and an immunohistochemical examination suggested a uterine adenomatoid tumor. Our suspicion of a borderline tumor was based mainly on the following features: the mass had increased in size within 1 year, the cancer antigen 125 concentration had increased, and several lymph nodes in the pelvic and groin regions showed positive signals on MRI enhancement. Uterine adenomatoid tumors are challenging to diagnose, especially adenomatosis with signet ring cells. However, the accuracy of diagnosing this disease can be greatly improved by combining ultrasound and MRI. This article describes the most comprehensive and reliable imaging features of ultrasound and MRI, which play an important role in diagnosing uterine adenomatoid tumors and provide useful information for clinicians.