Progressive Hemifacial Atrophy, also known as Parry-Romberg Syndrome, is an uncommon degenerative and poorly understood condition. It is characterized by a slow and progressive atrophy affecting one side of the face. The incidence and the cause of this alteration is unknown. A cerebral disturbance of fat metabolism has been proposed as a primary cause. This can be the result of a trophic malformation of Cervical Sympathetic Nervous System. Possible factors that are involved in the pathogenesis include trauma, viral infections, heredity, endocrine disturbances and auto-immunity, among others. The most common complications that appear in association to this health disorder are: trigeminal neuritis, facial paresthesia, severe headache and epilepsy, being this last one the most frequent complication of the Central Nervous System. Characteristically, the atrophy progresses slowly for several years and, soon after, it become stable. Now, plastic surgery with graft of autogenous fat can be performed, after stabilization of the disease, to correct the deformity. Orthodontic treatment can help in the correction of any associated malformation. The objective of this work is, through the presentation of a clinical case, to accomplish a literature review concerning general characteristics, etiology, physiopathology, differential diagnosis and treatment of progressive hemifacial atrophy.