The incidence of primary total elbow arthroplasty (TEA) in young patients is increasing. The indications for revision surgery are also rising. Here, we report a rare case of pseudotumor detected in a patient 16 years after TEA. Intraoperative findings revealed a necrotic mass characterized by a conspicuous metallosis in the soft tissues around the prosthesis, which caused ulnar nerve dislocation. Due to this anatomical change, a lesion of the nerve was accidentally produced during revision surgery. The case report emphasizes that the indications for elbow replacement, as well as the patient education about the permanent physical limitations, should be carefully considered. Moreover, the high risks of complications related to the revision procedure and pseudotumor removal need to be addressed before surgery. The technique should be done carefully and a preliminary thorough imaging should be performed, since a newly formed mass can cause significant distortion of the anatomy.