Hemifacial hyperplasia: a case series and review of the literature.

Condylar hyperplasia is known to result in facial asymmetries and constitutes a well-recognized group of unilateral mandibular enlargements. Condylar hyperplasia has been sub-classified into hemimandibular hyperplasia and hemimandibular elongation. A much rarer disorder, hemifacial hyperplasia (or hemifacial hypertrophy) is a congenital malformation characterized by prominent unilateral overdevelopment of the hard and soft tissues of the face. The affected side grows at a faster rate than the non-affected side, creating a marked asymmetry that potentially involves the skeleton and teeth, as well as all components of the associated soft tissues. Hemifacial hyperplasia is usually identified at birth and progresses towards puberty, but is not thought to alter throughout the lifetime of affected individuals. A case series of five patients clinically diagnosed with hemifacial hyperplasia is presented, with the aim of reviewing the clinical features, discussing their individual surgical management, and summarizing the more recent identification of possible genetic mutations that may be responsible for hemifacial hyperplasia and related overgrowth disorders. It is speculated that depending on the genetic factors, the disorder may be progressive in specific cases.