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
