Publication:

Incidental finding of a polycystic and papillary tumor in a case of inguinal hernia repair and inguinal nerve entrapment: a case report

Groin pain is a common clinical complaint and is often misdiagnosed as an adductor strain or as pubic bone inflammation. While inguinal hernia repair is one of the most frequent surgical procedures, histological examination of the hernia sac is rarely performed. Tumors arising within the hernia sac are highly uncommon, making this case of mesothelioma particularly noteworthy. Herein this report presents the case of a 32-year-old White male athlete of European descent who presented with chronic left-sided groin pain. An open herniotomy was indicated due to a hernia and isolated nerve entrapment. Intraoperatively, a hernia and isolated nerve entrapment in the external oblique aponeurosis were confirmed. A cystic structure was discovered incidentally in the region of the hernia sac. The hernia sac and cysts were completely removed and sent for histological examination. Histologically, subepineural edema and perineural fibrosis of a nerve consistent with chronic injury were diagnosed, as well as a completely removed polycystic papillary mesothelial tumor in the region of the hernia sac. The case of inguinal mesothelioma illustrates the importance of histological examination, differential diagnosis, and interdisciplinary analysis in chronic groin pain. While routine histological examination of inguinal hernia sacs is not standard practice, specific intraoperative findings—such as non-intestinal contents, atypical tissue characteristics, unexplained clinical symptoms, recurrent hernias, or suspected malignancy—warrant histopathological evaluation to ensure comprehensive patient care. In cases of inguinal pain, establishing a causative differential diagnosis, such as ilioinguinal nerve entrapment and benign polycystic mesothelioma in the hernia sac, is of paramount importance for successful treatment.