Recognition of an incidental abscess and a hematoma during ultrasound-guided femoral nerve block.

Ultrasound guidance for femoral nerve blockade allows visualization of normal and abnormal anatomy. Two cases of femoral nerve blockade under ultrasound guidance are presented where a major perineural pathologic lesion was incidentally revealed. These pathologic lesions, an abscess and a hematoma, resulted in significant adaptations in clinical care and have not been reported previously. We review and discuss incidental pathologic lesions that can be found in the femoral region. Identification of these 2 pathologic lesions facilitated our perioperative management strategies in two separate cases.