Inguinal Hernia Repair Mimicking Cancer On PET-CT: Mesh Is Cool, but the Plug Lights Up

Objectives PET/CT imaging in the postoperative setting may show FDG uptake at the surgical site. The uptake pattern in general is easily recognizable, thereby avoiding its misinterpretation as malignancy. However, we observed that imaging findings following inguinal hernia repair are not always easy to recognize and can mimic malignancy. This is particularly so with plug repair, which shows an FDG-avid, mass-like pattern on PET/CT.

Methods A retrospective search was performed at our institution for inguinal hernia on PET/CT performed during 2014. This search yielded 32 patients (pts) (2 F, 30 M) meeting this criteria. Images and medical records of these 32 pts were reviewed to assess the type of prior hernia repair, if any. In addition, PET/CT images were reviewed to assess the imaging findings associated with hernia and/or its repair.

Results Of 32 pts, 17 had inguinal hernia repair with plug, 7 had mesh repair, 5 had simple fat-containing hernias without surgical repair and 3 had uncomplicated bowel-containing inguinal hernias without surgical intervention. All 17 pts with plug repair demonstrated FDG avid postsurgical changes, and the plug mimicked a soft tissue mass on CT. None of the 7 pts with mesh repair had increased FDG activity or an appearance of mass on CT. Five pts with simple fat-containing hernias did not demonstrate increased FDG activity, while 3 pts with uncomplicated bowel-containing hernias had physiologic FDG activity within the herniated bowel loops.

Conclusions It is crucial to recognize that inguinal hernia repair by plug invariably demonstrates FGD activity at the site of repair. An appearance of FDG-avid soft tissue mass, without the knowledge of prior surgery and/or awareness of image pattern can result in misinterpretation as hypermetabolic mass/ lymph node. Careful correlation with corresponding CT images for evidence of surgical intervention and review of clinical history are crucial to avoid this misinterpretation.

Research Support None.