Congenital partial hypoplasia of the lower lip: a rare form of 28-29 Tessier cleft?Olina Rios (a), Virginie Lafontaine (b), Cyril Debortoli (a), Charles Savoldelli (a), Beatrice Morand (b)Corresponding author: [email protected](a) Department of Oral and Maxillo-facial surgery, Head and Neck Institute, University Hospital Center of Nice, 06100 Nice, France(b) Department of Maxillo-facial and Plastic surgery, University Hospital Center of Grenoble-Alpes, 38000 Grenoble, FranceKey Clinical Message:We aim to describe a case of congenital partial hypoplasia of the lower lip in a 2-year-old child. As this anomaly was associated with other oral anomalies, we explored the possibility of a modified 28-29 Tessier cleft. However, other hypotheses were proposed as we may be dealing with an unknown mechanism.Keywords: labial hypoplasia, lower cleft lip, craniofacial abnormalities, Tessier clefts.Introduction:First described by Couronne in 1819, cleft mandible and/or lower lip is one of the rarest craniofacial clefts with less than 100 cases reported in the literature 1,2. In almost all cases, the midline location of the lip and/or mandible has been noted. According to Tessier’s classification of 1976, cleft lip and/or mandible midline is defined as no. 30.The paramedian lower cleft lip is even rarer, with only 5 cases described. However, in these cases the defect occurs in a very specific part of the lower lip and/or mandible. In the case described below, there was a defect of the entire lateral third of the lower lip. Therefore, it could not be formally associated with a 28-29 Tessier cleft and may not have the same origin.Case history:We aim to report the case of a 2-year-old boy who was born with hypotrophy of the lateral third of the lower lip. To the best of our knowledge, this type of anomaly has not been previously reported in the literature. Written informed consent was obtained from the parents of the child. This case report was submitted with their consent and with the approval of the Ethics Committee of the Face and Neck Institute.The patient was first referred to the craniofacial cleft team at the Grenoble University Hospital Centre at the age of 5 months. He was the first child of healthy parents with no consanguinity. The pregnancy was spontaneous, and the mother had a previous miscarriage. There was a family history of congenital dental anomalies: the mother’s aunt had only milk teeth and the mother of our patient was missing two permanent teeth (34 and 44). There was no exposure to teratogens or x-rays during pregnancy. The mother was 30 years old at the time of delivery. The boy was born at term by normal vaginal delivery. Birth weight was 3215 g with a cranial circumference of 35 mm. The Apgar score was 10/10. He didn’t have any other anomalies.Investigations:Cardiological examination and echocardiography were normal. Feeding was normal, although the parents noted a tendency to drool due to difficulties in achieving complete lip closure. Growth was normal. Examination revealed hypoplasia of the right lateral third of the lower lip (Figure 1A). There was no facial paralysis and the smile appeared symmetrical. Intra-oral examination revealed a gingival notch, a mucosal bridle and the median labial frenulum was deviated on the right side (Figure 1B). Lip eversion was possible. There were no abnormal findings on the tongue, oral mucosa, pharynx or tonsils, but a kystic lesion was visible on the anterior part of the uvula. No abnormality was seen on the rest of the body. Circumscriptions and amputations of digits or limbs weren’t noticed. As the development was normal, a simple follow-up with an annual visit was chosen.