Pseudomalignant Myositis Ossificans of the Proximal Phalanx: A Report of Two Cases

This report presents two cases of pseudomalignant myositis ossificans (PMO) of the fifth proximal phalanx and their management. The charts, X-rays, pathology specimens, and clinical outcome for two patients treated for PMO were retrospectively reviewed. Both patients presented with isolated swelling and pain over the proximal phalanx of the fifth digit and underwent biopsy of the lesions. In both cases the pathology results were conclusive for PMO. Both patients had improvement in pain and swelling postoperatively. There was no recurrence in either patient. PMO can easily be confused with a malignancy. Proper workup, including biopsy, should be performed in order to accurately make the diagnosis. Radical procedures or amputations should not be performed until a diagnosis has been made. Excision is indicated when nerve compression or loss of joint motion secondary to mass effect occurs. Historically, recurrence has not been a problem after excision. (Journal of Surgical Orthopaedic Advances 15(2):105–110, 2006