Fibrolipoma of the Median Nerve: An Overview

Introduction: Fibrolipoma of the median nerve is a rare benign lesion responsible for carpal tunnel syndrome. Fibrolipoma is often misdiagnosed. This article aimed to review and summarize current knowledge regarding fibrolipoma of the median nerve. We emphasize the clinical and imaging features of this disease. Methods: To examine the characteristics of fibrolipoma of the median nerve, we performed a litera-ture review using MEDLINE. The search included only English studies published from database in-ception to June 2021. Results: Forty-six cases of fibrolipoma of the median nerve were included. Fibolipoma is characterized by diffuse infiltration of peripheral nerves by normal-appearing fibrous and adipose tissues. The fibrolipoma of the median nerve can be responsible for macrodactyly, numbness, paresthesia, and weakness within the median nerve distribution. Ultrasonography shows a fusiform hyperechoic mass along the nerve containing hypoechoic bands corresponding to nerve fascicles. Magnetic resonance imaging is the gold standard for the diagnosis of fibrolipoma. It typically shows a contrast between the low signal nerve fibers and the high signal fatty tissues, revealing a characteristic « cable-like » appearance on axial sections and a «spaghetti-like» appearance on coronal sections. Conclusion: Fibrolipoma should be considered in young patients with carpal tunnel syndrome. This review emphasizes the clinical and radiological features of fibrolipoma. We highlight the images of ultrasonography in the diagnosis of rare structural causes of carpal tunnel syndrome.