Presentation
Progressive forearm deformity.
Patient Data
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There is resorption of a portion of the ulnar shaft at the junction of the middle and distal thirds. There is a narrow sharpened pencil-like appearance of the ulnar distal to the absent section with cupping of the ulnar proximal to this, mimicking the appearance of a joint.
Case Discussion
This abnormality is rare and has been termed ulnar pseudoarthrosis and is usually only seen in patients with neurofibromatosis type 1 (NF1) which was true in this case. Involvement of the ulna is uncommon with tibial pseudoarthrosis being many times more prevalent in patients with NF1.