Background: Extrapelvic endometriosis is the most-common form of abdominal-wall endometriosis (AWE). This rare condition usually results from transport of endometrial tissue into incision sites of surgical operations or adjacent tissues. Spontaneous AWE also occurs. A common symptom is a painful and tender mass usually associated with menstruation. Noncyclic pain can occur in 45% of patients. Standard treatment is complete surgical excision. Case: This 44-four-year-old patient, gravida 0, presented with persistent cyclic pain in her right inguinal area, but she had no history of previous abdominal surgery Ultrasonography (USG) showed an obscure, heterogeneous-hypoechogenic mass of similar to 2.0 x 1.5 cm in the right lower quadrant of her abdominal wall. She underwent total surgical excision by ultrasound-guided-wire localization. Results: The nonpalpable mass that was localized via an ultrasound-guided wire was surgically excised. A diagnosis of AWE was confirmed by histopathologic examination of the mass. Two months postoperatively, this patient's pain disappeared. Conclusions: Extrapelvic endometriosis can be located in almost any organ of the body, including the abdominal wall. The incidence of AWE is reported to be up to 0.03%-3.5%, and most cases of AWE commonly arise in an incision made during a cesarean section. Spontaneous AWE is less common, compared to cesarean-scar endometriosis. The diagnosis of AWE is difficult due to its rarity, subclinical presentation, and generally nonpalpable lesions. Ultrasound-guided-wire localization is a reliable, simple, and practical solution for localizing nonpalpable lesions.