LAUSR

A 41yearold man presented with right knee pain for 3 months. Physical exams noted a positive Hughston plica test (ie, the presence of pain or a popping sensation during flexion and extension of the knee while the tibia is internally rotated, indicative of an abnormal plica). An xray revealed multiple radiopaque lesions in bilateral knees (Figure, A, arrows) and in all periarticular bones (Figure, B, arrows). A magnetic resonance imaging scan revealed benign, hypointense lesions on T1and T2weighted images (Figure, C, arrows), compatible with osteopoikilosis. Due to persistent pain, he underwent an arthroscopy of the right knee, which showed normal articular cartilage with synovitis secondary to a medial plica (Figure, D [F = femur; T = tibia; * synovium]). Successful resection of the medial plica was performed; the pain disappeared and the patient was able to return to his usual daily activities without difficulty. Osteopoikilosis is an autosomaldominant disorder with a prevalence of one in 50 000 population.1 This condition can be associated with a mutation to the LEMD3 gene and is characterised by sclerosing bone dysplasias.2 In addition, these patients may be associated with dermatofibrosis, scleroderma and dwarfism.3 The lesions are benign, and if asymptomatic, further workup is unnecessary.3 The asymptomatic presentation and relatively benign radiologic appearances differentiate this condition from metastatic cancer, tuberous sclerosis, and other diseases.3,4