Condylar hyperplasia (CH) is a rare disorder characterized by excessive growth of the mandibular condyle in the horizontal and/or vertical dimensions. It usually presents unilaterally and can result in facial asymmetry, malocclusion and temporomandibular joint disorders. The etio-pathogenesis of CH is uncertain and has been associated with hormonal factors, trauma, heredity, hypervascularity, aberrant growth factors, infection and neoplasia. A variety of specialized nuclear medicine studies (e.g. scintigraphy, PET-CT and SPECT) are utilized to determine if there is pathological growth activity in the suspected condyle. It is essential to identify the condition as mis-diagnosis can lead to unexpected adverse growth even after the surgical correction of facial asymmetry. The authors report a case in a 16-year-old male subject who developed facial asymmetry (due to unilateral active CH) while undergoing routine orthodontic treatment for maxillary dento-alveolar protrusion. The patient was treated by high condylectomy and has been followed up for 1 year without signs of active growth. This paper also provides a mini-review of the recent literature on the epidemiology, etiology, diagnosis, classification, and surgical treatments of CH.