Spontaneous intraneural hematoma of the common fibular nerve due to oral anticoagulation.

Compression syndromes affecting the common fibular nerve are common and frequently caused by direct pressure upon the fibular tip region. Here, we describe a case of a 50-year-old male presenting with sudden foot drop, which had developed spontaneously. He was on oral anticoagulants due to hereditary thrombophilia (factor-V-Leiden). Neurophysiology examination revealed a common peroneal nerve lesion at the fibular tip. T1-weighted magnetic resonance imaging (MRI) showed a not further classifiable hyperintensity within the common peroneal nerve. Surgical exploration revealed a diffuse intraneural hematoma, which was not evacuated. During follow-up, the nerve function recovered almost completely. In retrospect, MRI findings indicated a hematoma supported by the history of anticoagulant medication.