Atypical expanded-spectrum hemifacial microsomia: a case report.

Objective : To present the case report of a patient with expanded hemifacial microsomia (HFM) that illustrates the complex interactions of these embryogenic factors and to review current theories and mechanism regarding the etiopathogenesis of HFM. Design and Method : We present the case of an African American girl who was born at full term by cesarean section and transferred to our institution for systemic malformations. Her craniofacial findings include holoprosencephaly, cleft lip and palate, low set and posteriorly rotated ears, flat midfacial features, micrognathia, left HFM with grade 1 microtia, hypoplastic mandible, and a small preauricular pharyngeal arch remnant. Systemic anomalies included ectopic kidney, atrial-septal defect, bilateral hip dysplasia, bilateral humeroradial fusion, bilateral club feet, and bilateral low-set thumbs with the right side also being triphalangeal. Genetic evaluation did not identify a molecular diagnosis or other known syndrome. Conclusions : Although vasculogenic disruption of the stapedial artery during early fetal gestation has been implicated in the etiology of HFM, the grouping and bilateral findings seen in our patient argue against this relatively simple and localized phenomenon. Instead, such diverse and widespread anomalies in the setting of expanded spectrum HFM seem to support the theory of a disorder in blastogenesis as the cause of HFM.