A pictorial overview of abdominal wall endometriosis

Abdominal wall endometriosis localizes between the peritoneum and the skin, including adipose tissue, abdominal rectus muscle, umbilicus, and inguinal canal.

Key Points

Highlights:

• An obstetric or gynecological surgery history, palpable abdominal wall mass, and menstrual pain in a woman of reproductive age are suspicious findings for abdominal wall endometriosis.

Importance:

• Abdominal wall endometriosis is more frequently diagnosed due to the increasing incidence of cesarean section.

What’s done here?

• This review was written to identify abdominal wall endometriosis, its localizations, diagnosis, and treatment options.
• The importance of past medical and surgical history also provides diagnostic clues.
• Abdominal wall endometriosis can be located anywhere through the abdominal wall between the peritoneum and the skin.
• Cutaneous endometriosis is defined as ectopic endometrial tissue lokalized on the skin, with an incidence of < 1% of ectopic sites.
• The incidence of umbilical endometriosis, also known as "Vilar node", is about 0.5–1% of endometrial ectopy.
• The most frequent form of abdominal wall endometriosis is subcutaneous endometriosis, loacated superficially to the rectus abdominis muscle fascia.
• If the ectopic endometrial mass infiltrates the muscle layer and locates inside the rectus abdominis, it is named "intramuscular endometriosis".
• Inguinal canal endometriosis is one of the possible causes of inguinal mass, and often confused with inguinal hernia.

Key Results:

• Abdominal wall endometriosis is formed by seeding endometrial cells through the abdominal wall during obstetric or gynecological surgery.
• Imaging modalities, especially ultrasound, are helpful for differential diagnosis.
• Hypoechogenic heterogenous nodules with indistinct edges and intralesional vascular spots on USG, harder pattern compared to the surrounding tissues on elastosonography are typical.
• Unless the patient has a surgical risk, the gold standard treatment method is surgical excision.
• Sclerotherapy, high-intensity focused ultrasound ablation, cryoablation, or combined oral contraceptives are options for patients with high surgical risk or refusing surgical intervention.

Lay Summary

Abdominal wall endometriosis is the most frequent location of extrapelvic endometriosis, and defined as the presence of ectopic endometrial tissue between the peritoneum and the skin through the abdominal wall. Although obstetric or gynecologic surgical history is indispensable for the development of abdominal wall endometriosis, it can rarely be encountered in some women as primary, without any previous operations. The incidence of abdominal wall endometriosis is approximately 3.5% in patients having past gynecological surgery and 0.8% in those with a previous cesarean section.

Cocco et al, from Italy, published a review entitled Ultrasound Imaging of Abdominal Wall Endometriosis", A Pictorial Review in the journal "Diagnostics".  The authors reviewed the literature to provide a practical overview of ultrasonography of abdominal wall endometriosis.

The presence of ectopic endometrial tissue through the abdominal wall including skin, subcutaneous tissue, umbilicus, rectus abdominis muscle, and the inguinal canal is defined as the abdominal wall endometriosis. Palpable and painful nodules, pain strongly correlated with the menstrual cycle, on the abdominal wall in a reproductive-aged woman are suspicious findings.

Hence personal history and physical examination are important for diagnosis, and imaging methods such as ultrasound are also necessary for the differential diagnosis of abdominal wall endometriosis. Definitive confirmation of the diagnosis is provided by histopathological examination of surgically excised specimen. As long as there is no surgical risk or refusal, surgical excision with a margin of 1 centimeter is the gold standard treatment method. Sclerotherapy, high-intensity focused ultrasound ablation, cryoablation, or combined oral contraceptives are therapeutic options for patients with high surgical risk or refusing surgical intervention.      

“Abdominal wall endometriosis following obstetric and gynecological surgery is becoming more frequently diagnosed due to the increasing number of cesarean sections worldwide,” the authors added.  

Research Source: https://pubmed.ncbi.nlm.nih.gov/33805519/