Multimodality imaging and clinicopathologic assessment of abdominal wall endometriosis

Familiarity with the radiologic features of abdominal wall endometriosis prevents the delay in diagnosis.

Key Points

Highlights:

• A better comprehension of abdominal wall endometriosis and familiarity with its radiologic findings will allow more accurately diagnose an abdominal wall mass in a female of child-bearing age.

Objectives:

• To provide detailed clinicopathologic and radiologic assessments across imaging techniques in patients with endometriosis in the abdominal wall.

What's done here:

• In this retrospective study, 116 women who had a histopathologic diagnosis of extragenital endometriosis between 2014 and 2017 were evaluated.
• Of 116 patients, 26 had abdominal wall endometriosis. Patients who had the prebiopsy or presurgical imaging studies and sufficient field of view to assess the lesion were included in the study. Eighteen patients fulfilled these criteria.

Key results:

• Most of the patients presented with abdominal pain and a palpable mass with a mean size of 2.5cm; deposits more commonly located in the midline or in the left hemiabdomen.
• The lesions had either round or stellate shape, had ill-defined margins and involved both superficial and deep layers of the abdominal wall.
• The most common ultrasound pattern was a mixed echogenicity. On CT, AWEs were mostly hypervascular and homogeneous, superiorly located to scar tissue.
• MRI revealed that the lesions appeared hyperintense to muscle with T2 cystic and T1 hemorrhagic foci.
• Diagnostic rates of abdominal wall endometriosis by CT and ultrasound were found to be very low whereas MRI was high (75%).
• Endometriosis should be considered in the differential diagnosis of abdominal wall lesions that are hyperintense on T1 and variable on T2-weighted imaging.
• Desmoid tumors, hematoma, keloids, neuromas, sarcomas, sarcoidosis, granulomas, metastases, and lymphoma may closely resemble the spectrum of AWE radiologic appearance.
• Abdominal wall endometriosis can rarely undergo malignant transformation (%1).  The median time between onset of symptoms and histopathology diagnosis was two years.

Limitations:

• This study has a limited sample size and a retrospective nature.

Lay Summary

Abdominal wall endometriosis is a rare clinical entity frequently diagnosed with a significant delay and easily misinterpreted despite multimodality imaging.

In the study of Jaramillo-Cardoso et al. which has recently been published in the journal Abdominal Radiology, the clinical, multimodality imaging, and pathologic characteristics of endometriosis in the abdominal wall were reviewed.

Eighteen patients who had the prebiopsy or presurgical imaging studies and sufficient field of view to assess the AWE lesion were included in the study.

Patients presented with abdominal pain in 14/18 cases, which was cyclical in 8/14; palpable mass in 12/18; fluid discharge in 2/18; and local skin discoloration in 2/18.

Abdominal wall endometriosis lesions were more commonly located in the midline or in the left hemiabdomen, have a variable round/stellate shape and margins by imaging, with an approximate size of 2.5cm. Ultrasound was the most common modality used to image AWE and showed moderate vascularity with peripheral distribution. On CT and MRI, AWE most commonly seen as a heterogeneous hypervascular lesion showing T2 hyperintense areas with T1 hemorrhagic foci. 

Endometriosis was undiagnosed by CT and ultrasound in 100% and 77% of cases, respectively. In contrast, 75% of the lesions were correctly diagnosed by MRI. The changes in AWE cellular composition across cyclic hormonal influences, chronic inflammation, and fibrotic changes cause T2-intensity. Abdominal wall endometriosis lesions were found to display mixed echogenicity on ultrasound in contrast to the common teaching that most present as hypoechoic lesions. Desmoid tumors, hematoma, keloids, neuromas, sarcomas, sarcoidosis, granulomas, metastases, and lymphoma may closely resemble the spectrum of abdominal wall endometriosis radiologic appearance.

Although most of the older literature agrees on the minimal impact of imaging in the management of these patients, the researchers of the current study state that the appropriate imaging and recognition are important regarding the development of minimal-invasive therapies such as percutaneous cryoablation and radiofrequency ablation for abdominal wall endometriosis.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/30003273