Neural fibrolipomas are often characterized by a mass under the skin accompanied with sensory deficit in the same area or a painful sensation.
Some common nerves that are affected are the median, ulnar, radial, perineal, and brachial plexus.
[4] Taking a biopsy of the mass is not necessary because these are distinct enough to make a confident diagnosis only from the use of medical imaging, like an MRI.
However, if a biopsy is taken, it will show an abundance of mature fat cells surrounded by fibrous connective tissue.
[5] Neural fibrolipomas are often associated with carpal tunnel syndrome, due to both of their correlation with the median nerve.