Rectus abdominis muscle endometriosis Report of two cases and review of the literature.

Endometriosis involving the rectus abdominis muscle is very rare; until now, only 19 such cases have been reported in the medical literature since it was first described in 1984 by Amato and Levitt; almost all were associated with previous abdominal surgery such as cesarean section or other operations. We report two additional cases of this very rare condition presenting with an abdominal mass which was surgically excised with an accompanying margin of normal tissue. Both patients are well and without recurrence. Endometriosis pain has generally been described as cyclical and this condition usually develops in an old surgical scar. Endometriosis has no pathognomonic imaging findings on CT, MRI or sonography, as its appearance depends on the phase of the menstrual cycle, the proportion of stromal and glandular elements, the amount of bleeding and the degree of surrounding inflammatory and fibrotic response. Surgery is the treatment of choice including 5-10 mm of surrounding healthy tissue as surgical margin, to prevent recurrence. Our experience is in agreement with the data of the literature. We suggest that endometriosis must be included in the differential diagnosis of a symptomatic mass in the abdominal wall in women with and without a surgical history. Key words: Endometriosis, Rectus abdominis muscle, Surgery.