Abstract
INTRODUCTION: Congenital hypoplasia of the depressor anguli oris muscle is a rare mimic disorder depicted by a lower lip asymmetry apparent when laughing or crying. PRESENTATION OF CASE: A 10-year-old boy consulted our department for an asymmetry when opening his mouth. According to the family, this asymmetry was present since birth. Perinatal characteristics and childhood medical history were investigated with no abnormalities. Physical exam revealed an inability to draw down the right lower lip unilaterally. At rest position, facial asymmetry was not noticeable. Several investigations were done: A CT scan of the petrous part of the temporal bone, an MRI of soft tissues, an electromyography and a heart ultrasound. No anomalies were found. DISCUSSION: This condition has stimulated great interest because of its potential association with congenital anomalies but also in order to reassure families often worried by the situation. A large therapeutic armamentarium is described in literature. CONCLUSION: Among the large armamentarium of therapeutic options, we opted for a wait and see strategy through photographic smile tracking leading to an evidence of Asymmetric crying faces over time improvement.