Lipomatosis of nerve is a benign lesion with increased fibrofatty tissue infiltrating and surrounding nerves, usually occurring in children and young adults as a slowly progressive swelling or mass, which can clinically mimic a tumor or malignancy. Here we report a 59-year-old man who presented with pain in his right foot and a mass that has been mostly stable for years, but which seems to have grown slightly of late, and is clinically suspicious for ganglion cyst. The MRI revealed a fatty mass concerning for lipoma or atypical lipomatous tumor. Consequently, the patient underwent excisional biopsy. The H&E sections showed mature adipose and fibrous tissue infiltrating the nerve, consistent with lipomatosis of nerve. Lipomatosis of the nerve, though most common in upper extremities, can occur in a variety of locations, and providers should be aware of potentially rare presentations like this one to prevent unnecessary surgery and prevent potential nerve damage.
Alam, Mehruba and Wasden, Thomas Benjamin Lyle, "Lipomatosis of Nerve" (2023). Annual Research Symposium. 3.