Fibrolipomatous hamartomas of nerve are
rare, benign, fibrofatty malformations of peripheral nerves.
Other terms applied to this condition are
neural fibrolipoma, lipofibromatous hamartoma of nerves and
Most cases occur in
the first 3 decades of life (often at birth or early childhood)
and a third are associated with macrodactyly which is referred to as
enlargement of one or several digits of the hands or feet (macrodactyly)
is a rare disorder. The majority of the cases reported in the literature
represent hamartomas with combined hypertrophy of several, predominantly
lipomatous, soft tissue components and overgrowth of bone. The
differential diagnosis includes Klippel-Trenaunay-Weber
syndrome, neurofibromatosis, Milroy disease, and Proteus syndrome.]
The upper extremity is commonly involved with a marked predilection for
the median nerve.Other sites include the lower extremity,
ulnar nerve, radial nerve and brachial plexus.
presents as a soft slowly growing fusiform swelling consisting of
fibrofatty tissue surrounding and infiltrating major nerve and its
branches (most often median and rarely ulnar nerve).
Swelling may be accompanied by increasing, pain, tenderness and diminished
There may be symptoms of compression neuropathy similar to carpal tunnel
syndrome in some of the lesions.
The affected nerve is diffusely
Soft tan-yellow fusiform mass diffusely infiltrate and replace
portions of the nerve.
The nerve trunk is surrounded and
infiltrated by fibrofatty tissue.
The epineurium of the affected nerve is expanded by fibrofatty tissue.
lesion has a diffuse infiltrative character.
Nerve fascicles are well
Perineural fibrosis may be present.
Prolonged compression of
nerves by fibrofatty tissue may result in neural degeneration and atrophy.
In fibrolipomatous hamartoma
there is atrophy rather than proliferation of neural elements.
Diffuse lipomatosis: This is a lesion of subcutis and muscle and only
secondarily affects nerves.
There is no effective treatment for this lesion. Biopsy of the mass
will establish the diagnosis. Excision of the lesion is contraindicated
because it may lead to significant sensory and motor disturbances.