Clinical and imaging features of abdominal wall endometriomas.

Abdominal wall endometrioma (AWE) is a rare condition (incidence 1% following caesarean section) with a significant variation in clinical symptoms, imaging findings and interval between initial procedure and diagnosis. We present two cases with differing clinical presentations. AWE may be difficult to diagnose pre-operatively, with as many as 75% of lesions diagnosed incorrectly prior to surgical excision. Ultrasonography is a useful tool in determining the extent of the endometrioma and can help exclude differential diagnosis such as hernia. Ultrasound appearance of AWE is often variable; however, the most common presentation is of a solid hypoechoic mass lesion with peripheral vascularity. Margins may be irregular and infiltrate the surrounding soft tissues. Lesions may be cystic or multicystic or may have both solid and cystic components. Power Doppler may demonstrate internal vascularity. If ultrasound findings are inconclusive, computed tomography (CT) or magnetic resonance imaging (MRI) should be considered to assist in making the diagnosis. Ultrasound-guided fine needle aspiration of the lesion may assist in the diagnosis, but seeding of the needle tract has been reported and must be included in the resection margins. Sonoelastography has shown some promise in early studies for improving diagnostic accuracy for AWE.