Cesarean Scar Endometriosis
A-32-year-old G1P1 woman presented at the outpatient clinic complaining of a painful lump at the bottom of her abdomen. She had an emergency cesarean delivery five months ago due to fetal distress. Otherwise, she has unremarkable medical and surgical history. She mentioned that the mass size increases slightly and the pain exacerbates during menstruation. She did not notice any bloody discharge from the lump. The lump was located over the right end of the cesarean scar. The overlying skin was bluish. Upon palpation, the nodule was tender, soft, with irregular borders. No inguinal lymphadenopathy was observed.
4×5 cm hypoechoic nodule with peripheral vascularization.
Magnetic resonance imaging
Invasion of the mass into the rectus abdominis sheath
Presence of endometrial-like glands and stroma that invaded the rectus sheath and the subcutaneous tissue.
Immunohistochemistry revealed intensive expression of estrogen receptors in the glandular component and immunopositivity to CD-10 in the stromal component. Therefore, abdominal wall endometriosis was diagnosed
Local excision of the nodule and repairing the defect in the rectus sheath with a mesh
Abdominal wall endometriosis is a very rare extra-pelvic localization of endometriosis. Although its exact incidence is not known precisely yet, it was reported to be 0.03-0.45%. Abdominal wall endometriosis is also referred to as scar endometriosis because it mostly originates on abdominal wall scars, such as cesarean and trocar site scars.
The suggested pathogenesis mechanism is direct spread of endometrial cells to the wound edges during surgeries that involves the uterus, such as myomectomies and cesarean sections. However, despite the increase in cesarean sections, the risk of developing endometriosis following a cesarean section is only 1.8%.
The typical presentation of abdominal wall endometriosis is a lump over a previous abdominal surgical scar that could increase in size during menstruation. Pain could be intermittent or persistent, with or without increasing intensity during menstruation. Some patients may report bloody discharge from the lump during menstruation, but others may not. The overlying skin could be bluish. CT scan and MRI are essential investigations to determine the extension of the lesion and the involvement of the abdominal wall muscles. Fine-needle aspiration is widely used to diagnose abdominal wall endometriosis. However, the diagnosis is only made upon visualizing microscopically the endometrial-like glands and stroma after total surgical excision of the lesion.
1) Gonzalez RH, Singh MS, Hamza SA. Cutaneous Endometriosis: A Case Report and Review of the Literature. American Journal of Case Reports. 2021 Sep 21;22.
2) Carsote M, Terzea DC, Valea A, Gheorghisan-Galateanu AA. Abdominal wall endometriosis (a narrative review). International journal of medical sciences. 2020;17(4):536.
3) Lopez-Soto A, Sanchez-Zapata MI, Martinez-Cendan JP, Reina SO, Mañas CM, Solano MR. Cutaneous endometriosis: Presentation of 33 cases and literature review. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2018 Feb 1;221:58-63.