Isolated Endometriosis on the Rectus Abdominis Muscle in Womenwithout a History of Abdominal Surgery: a Rare and IntriguingFinding

We report 2 rare cases of endometriosis on the rectus abdominal muscle diagnosed incidentally during an operation for inguinalhernia repair in women with no surgical history. Two women sought medical attention for a mass found in the pubic abdominalwall. Only 1 woman reported occasional pain. At physical examination in both women, an ovoid swelling in the right pubic areawas felt. One woman experienced pain on palpation, and one reported slight discomfort. Ultrasonography demonstrated a heterogeneoushypoechogenic formation with indistinct edges; diagnosis was difficult. Routine clinical and instrumental (pelvicultrasonography) gynecologic examination in both patients performed shortly before hospitalization had not revealed anymacroscopic focus of endometriosis in the pelvic region. At surgery, a lesion consistent with the diagnosis of endometriosiswas found, which was confirmed at histologic analysis. These cases could represent the consolidation of different theoriesof endometriosis diffusion. We suggest including endometriosis in the differential diagnosis of a symptomatic mass in theabdominal wall in women with and without a surgical history