Parry-Romberg syndrome (PRS) is an uncommon disorder and characterized by a slowly, an acquired progressive atrophy involving skin, soft tissue, cartilage, and bony structures. Accompanying atrophies of the other parts of the body are rarely reported. The aim of this study is to report a case that had contralateral lower extremity atrophy with PRS, and to review the related etiologic features, physiopathology, and mechanism.The patient who admitted for his facial atrophy also had atrophy of his contralateral extremity. This extremity was also short in length when compared with other extremity. To obtain detailed information regarding the severity of involvement routine laboratory investigations including antinuclear antibody (ANA), magnetic resonance imagine (MRI) of the craniofacial region and lower extremities, MR angiography of the lower extremities and brain, 3-dimension computed tomography (CT) scan of the craniofacial region were performed. Normal or negative laboratory findings included results of blood count, renal and hepatic function biochemical tests, rheumatoid factor, C-reactive protein, anti-dsDNA antibody except ANA that were positive. His lower extremity and brain MR angiography were normal. In the 3-dimensional cranial CT, there was no abnormality or defect in the bony structures. His brain MRI showed no pathologic changes, and his facial MRI demonstrated noteworthy atrophy to the sternocleidomastoid, masseter, pterygoid muscles, and subcutaneus soft tissues on the right side of the face. Additionally, MR investigation of his lower extremities revealed decreased volume in muscles and bony structures of the effected extremity compared with the other extremity, but pathologic evidence of fatty degeneration associated with muscle atrophy was not demonstrated.The patient had isolated contralateral lower extremity involvement combined with hemifacial atrophy (without affecting any other part of the body). Although more accepted theory is the sympathic nervous system dysfunction, autoimmunity may play a roll in the etiology of our case as ANA abnormality was found in multiple tests. © 2009 Lippincott Williams & Wilkins, Inc.