Table of ContentsDefinition / general | Terminology | Epidemiology | Sites | Radiology description | Case reports | Treatment | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosis
Cite this page: Singh C. Lipomatosis of nerve. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissueadiposelipomatosisnerve.html. Accessed May 7th, 2021.
Definition / general
- Infiltration of epineurium of a major nerve by adipose and fibrous tissue
- Also called fibrolipoma of nerve, fibrolipomatous hamartoma of nerve, macrodystrophia lipomatosa
- May be noted at birth
- Almost always age 30 years or less
- Associated with macrodactyly (abnormal enlargement of digits) innervated by affected nerve in 30 - 67%
- 85% have involvement of median nerve and its digital branches in hand, wrist and forearm (Histopathology 1994;24:391)
- Also ulnar nerve
- T1 weighted images on MR imaging reveal a fatty mass that is evenly distributed between nerve bundles and is seen running along individual nerves
- Often described as having a "coaxial cable-like" appearance on axial scans (Acta Radiol 2003;44:326)
- Benign but often no effective treatment as resection causes sensory and motor deficits (J Neurosurg 1998;89:683)
- Carpal tunnel release may relieve symptoms of median nerve involvement
- Amputation if severe deformity
- May recur in 33 - 60% if incomplete resection
- Fusiform enlargement of nerve by yellow adipose tissue, confined within epineurium
Microscopic (histologic) description
- Infiltration of epineurium and perineurium by adipose and fibrous tissue (collagen), causing enlargement of nerve
- Concentric perineurial fibrous tissue and pseudo-onion bulb formation
- Occasionally metaplastic bone
Microscopic (histologic) images
Contributed by Charanjeet Singh, M.D.
Contributed by Mark R. Wick, M.D.
Contributed by Saroona Haroon, M.D.
Images hosted on other servers:
- Diffuse lipomatosis: not confined to epineurium
- Intraneural lipoma: mass of fatty tissue displaces nerve bundles, but does not separate them
- Traumatic neuroma: onion bulb formation, usually lacks concentric perineural fibrosis, has high T2 signal density on magnetic resonance imaging
- Differential diagnosis of macrodactyly: