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Infantile hemangiomas frequently develop on the face and the majority of cases resolve without significant morbidity. Lesions which localize around certain anatomic locations, such as the eye and the beard, may be associated with regional complications such as amblyopia and airway involvement, respectively.1 Posterior fossa malformations have been linked to large facial hemangiomas, as well as arterial, cardiac, and eye anomalies, and midline sternal and supraumbilical defects, known collectively as PHACES syndrome.2 Occasionally, facial hemangiomas may ulcerate with resultant scarring. Why hemangiomas appear where they do and which hemangiomas develop complications has remained a mystery.
In this study, investigators retrospectively reviewed the records of 205 children with 232 facial hemangiomas who had been referred to the Vascular Anomalies Clinic of the Arkansas Children’s Hospital in Little Rock. The diagnosis of hemangioma was made on clinical grounds with histologic confirmation in a minority of cases. Attention was paid to where lesions appeared on the face and whether complications developed. The lesions were segregated on the basis of anatomic extent—as either focal or diffuse (segmental)—and then mapped on a standardized template to evaluate patterns of distribution.
The majority of hemangiomas (177/232 or 76%) were classified as focal, while the remaining were diffuse. The distribution of focal lesions localized to one of 22 clusters which each corresponded to margins of embryonic fusion planes known as facial placodes (see Figure). Most focal lesions occurred in the central face (60%). Diffuse hemangiomas were localized within areas marked by embryonal facial placodes of the frontonasal, maxillary, and mandibular areas or segments. Diffuse lesions were also far more commonly complicated by ulceration (51%) than focal lesions (17%). Systemic complications, such as subglottic airway involvement, were associated with diffuse hemangiomas within the mandibular distribution (38% of mandibular lesions) rather than focal hemangiomas (0%), even when the latter appeared in a beard distribution.
Commentary by Albert C. Yan, MD, FAAP
Pediatric Dermatology, Children’s Hospital of Philadelphia, Philadelphia, PA
This provocative series suggests that facial hemangiomas have a nonrandom distribution. Diffuse lesions, which distribute along and within segments defined by embryonal placodes, are more common among females than males (5.7:1) as compared with focal lesions (3:1). These findings imply that there is the possibility of a different pathogenesis for focal and diffuse hemangiomas.
That infantile hemangiomas distribute as they do may allow physicians to better predict the risk of complications. Questions remain as to whether infantile hemangiomas in other anatomic locations follow a similar paradigm; whether other vascular lesions distribute along similar embryonic planes of fusion or if this is unique to infantile hemangiomas; and why facial hemangiomas localize as they do along these anatomic sites.