Juvenile hemangiomas are the most common tumors of infancy, occurring in as many as 10% of all births. These benign vascular lesions enlarge rapidly during the first year of life by hyperplasia of endothelial cells and attendant pericytes and then spontaneously involute over a period of years, leaving loose fibrofatty tissue. Several hypotheses have been put forth concerning hemangiogenesis, including the possibility that the tumor is the result of somatic mutation in one or more components of critical vascular growth-regulatory pathways. To test this hypothesis, we obtained 15 proliferative-phase hemangiomas after surgical resection and dissected them to enrich for the lesional (endothelial and pericytic) components of each specimen. To determine whether hemangiomas represent a clonal expansion from a single progenitor cell, we assayed X-inactivation patterns for each lesion by using the polymorphic X-linked human androgen receptor gene. Twelve of 14 informative hemangiomas showed a significant degree of allelic loss after methylation-based and transcription-based polymerase chain reaction clonality assays, suggesting a nonrandom X-inactivation pattern and, thus, a monoclonal origin. We then sequenced genes encoding the receptors of the vascular endothelial growth factors (VEGFs) as candidates for potential somatic mutation. Mutations were found in two of the 15 hemangioma specimens: a missense mutation (P1147S) in the kinase domain of the VEGFR2 (FLK1/KDR) gene in one specimen and a missense mutation (P954S) in the kinase insert of the VEGFR3 (FLT4) gene in another specimen. In each case, the mutation was detected in tumor tissue but not in adjacent normal tissue. These results suggest that one potential mechanism involved in hemangioma formation is the alteration of the VEGF signaling pathway in endothelial and/or pericytic cells.

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Ear reconstruction is a difficult procedure requiring a framework and soft tissue covering. The traditional method uses a rib cartilage framework placed beneath scalp skin. This method has been used for 50 years despite inherent problems with both harvesting rib cartilage and using scalp for coverage. The authors describe a method using a porous polyethylene (PPE) framework covered by a large temporoparietal fascia (TFP) flap raised with the underlying subgaleal fascia (SGF). The entire implant is covered by the two-layered flap, which can be raised without any scalp incision. The skin grafts applied to the covered implant lie on the SGF. The trilaminar structure of the SGF allows the skin to move independently over the implant, resisting shear forces and reducing the probability of implant exposure. Ear reconstruction using the PPE framework was performed on 786 ears over an 18-year period. Initial complications were common. With improved implant design and complete coverage of the implant with both the TPF and SGF, exposure rate dropped to 7% with a 12-year follow-up. Implant fractures decreased to less than 3%. The PPE/TPF method allows earlier ear reconstruction in children with minimal scarring and discomfort. The reconstructed ear can closely mimic the shape and projection of the natural contralateral ear in fewer stages and with a shorter learning curve.

Several surgical techniques have been described for auricular reconstruction. Autologous reconstruction using costal cartilage is the most widely accepted technique of microtia repair. However, other techniques have certain indications and should be discussed with patients and families when planning for an auricular reconstruction. In the present review, the authors discuss the main surgical techniques for auricular reconstruction including autologous costal cartilage graft, Medpor (Stryker, USA) implant and prosthetic reconstruction. To further elaborate on the advantages and disadvantages of each technique, the authors invited leaders in this field, Dr Nagata, Dr Park, Dr Reinisch and Dr Wilkes, to comment on their own technique and provide examples of their methods.