Histopathologic examination of resected nerves from children with anterior cutaneous nerve entrapment syndrome: Clues for pathogenesis?

Background: Anterior cutaneous nerve entrapment syndrome (ACNES) has been described as a possible cause for chronic pain in the pediatric population. However, the exact pathophysiology of ACNES is unknown. It may be caused by compression or traction of cutaneous nerve branches of intercostal nerves, or it may be the result of an infection. Therefore, we present histopathological evidence to determine the pathophysiology of ACNES. Methods: A total of seven pediatric patients underwent a neurectomy for ACNES. All specimens were sent for histopathological evaluation, including immunohistochemical staining, to evaluate if there were any signs of infection, inflammation or compression. Results: Seven out of seven (100%) histopathological specimens showed non-specific nerve degeneration. Immunohistochemical evaluation showed there were several CD68-positive macrophages present in the specimens. Four out of seven (57%) specimens showed the presence of a few CD3-positive T-cells, however, this was not suggestive for inflammation or infection. Conclusion: Our study supports the hypothesis that ACNES is caused by compression of the nerves rather than inflammation. Level of evidence: III