Figure 12. Neuromuscular choristoma.
Neuromuscular choristoma is an exquisitely rare pseudoneoplastic lesion of nerve characterized by intrafascicular replacement of nerve by mature skeletal muscle (a,b). Immunohistochemistry for EMA highlights the outlining perineurium (c), while S100 and neurofilament protein label associated Schwann cells (d) and axons (e).