MRI Diagnosis of Fibrolipomatous Hamartoma of the Median Nerve and Associated Macrodystrophia Lipomatosa

Fibrolipomatous hamartoma is an uncommon congenital disorder, which is characterized by disproportionate hyperplasia of adipose tissue infiltrating along the perineurium, the epineurium and the affected nerve trajectory. We present a case of combined fibrolipomatous hamartoma and macrodystrophia lipomatosa of the median nerve. The involved sites included the left palm, wrist and forearm. Part of the patient's middle finger had been amputated due to previous macrodystrophia lipomatosa; however, the lesion continued to enlarge and was accompanied by numbness. Magnetic resonance imaging demonstrated a typical fibrolipomatous hamartoma with high signal intensity of fat on both T1-weighted and T2-weighted images, characteristic coaxial cable appearance on axial images, and spaghetti appearance on sagittal images. A similar skipped lesion at the median nerve of the middle forearm was also noted. To the best of our knowledge, this has not been reported in the English literature.