BACKGROUND: Popliteal fossa pseudoaneurysms as a result of trauma are not uncommon. However, spontaneous pseudoaneurysms as a result of non-traumatic rupture of posterior tibial artery (PTA), anterior tibial artery (ATA), or tibioperoneal trunk (TPT) artery segment are extremely rare. We report a case of spontaneous popliteal fossa pseudoaneurysm resulting from spontaneous avulsion of the ATA and transection of the TPT. Despite a thorough workup, no underlying associated disease was found. The extreme rarity of this disease presentation prompted us to report this case.

CASE REPORT: A 53-year-old female patient presented with a 10-day history of sudden onset of non-traumatic left popliteal fossa pain and swelling. A popliteal fossa pseudoaneurysm was diagnosed by duplex ultrasound examination. Computed tomography angiography (CTA) was performed to confirm the diagnosis and to plan treatment. Surgical exploration revealed avulsion of the ATA and transection of the TPT leading to a pseudoaneurysm. Autogenous popliteal-tibioperoneal trunk bypass was performed with uneventful recovery.

CONCLUSIONS: A spontaneous popliteal fossa pseudoaneurysm caused by non-traumatic ATA avulsion and complete transection of TPT is extremely rare. Yet, it can be the cause of limb loss if not recognized early and treated promptly. Awareness by the medical community will help reduce the potential morbidity associated with this condition.

Keywords: Aneurysm, False, Aneurysm, Ruptured, Tibial Arteries