Enormous Aneurysm of the Deep Femoral Artery: A Case Report.

Isolated true aneurysms of the deep femoral artery (DFAA) are exceptionally rare clinical entities. This report aims to describe the diagnostic challenges and therapeutic dilemmas associated with a huge 5.3 cm isolated DFAA in a patient with coexisting systemic hematological malignancy. A 77-year-old male patient with multiple myeloma underwent radiographic investigation for skeletal pain, which incidentally identified a 5.3 cm isolated left DFAA. Multi-planar CT angiography (CTA) characterized the lesion as a 10-cm long fusiform aneurysm featuring significant mural thrombus (3.7 cm thick) and irregular luminal ulcerations. Given the high risk of rupture, open surgical excision and ligation were recommended. However, following comprehensive clinical counseling regarding the natural history of the disease, the patient opted for conservative management with watchful waiting. Isolated DFAAs of this magnitude are rare and may be clinically masked by systemic pathologies such as multiple myeloma. This case highlights the diagnostic utility of CTA in characterizing complex vascular lesions and illustrates the ethical challenges that arise when patients decline indicated surgical treatment.