Craniofacial Microsomia With Tongue Cleft: Embryological Mechanisms and Clinical Implications From Three Rare Cases

Craniofacial microsomia (CFM) accompanied by a congenital tongue cleft is an exceedingly rare developmental anomaly, with fewer than 10 cases reported globally. This study presents 3 nonsyndromic cases of CFM with concurrent midline tongue cleft, characterized by mandibular hypoplasia (M2B), auricular malformations (E1-E3), soft tissue deficiencies (S1-S3), and hypoglossal/facial nerve dysfunctions. Despite the morphologic presence of tongue clefts, all cases were functionally benign and managed conservatively. Surgical treatment focused on mandibular distraction osteogenesis and auricular reconstruction, resulting in improved facial symmetry and function. The consistent involvement of first and second pharyngeal arch derivatives across cases suggests a shared embryopathological mechanism, likely involving disrupted cranial neural crest cell (cNCC) migration and dysregulation of key signaling pathways, such as SHH, BMP, and FGF. The study highlights the importance of tongue-mandible biomechanical coupling during embryogenesis and proposes potential genetic contributors, including FLNA and Meis2 mutations. These findings underscore the diagnostic significance of tongue cleft as an indicator of underlying craniofacial dysmorphogenesis and provide new clinical and mechanistic insights for future research and individualized therapeutic strategies.