The presence of functional endometrial tissue outside the endometrial cavity is defined as endometriosis. Although uncommon, endometrial tissue can become implanted into the abdominal wall musculature to form an endometrioma. Diagnosis is usually confirmed if there is the typical history of a mass in the abdominal wall after gynaecological surgery with symptoms that accompany menstruation. Tissue sampling confirms the histological diagnosis, but various imaging modalities (ultrasound, CT and MRI) can be used to further

characterize and delineate these lesions. Herein we report the case of an abdominal wall endometrioma which was evaluated by various imaging modalities and eventual histological diagnosis was established by tissue sampling with ultrasound guided core needle biopsy.