Sirolimus was efficacious and well tolerated in these study patients with complicated vascular anomalies. Clinical activity was reported in the majority of the disorders.

Rebound growth occurred in 25% of patients, requiring modification of systemic therapy in 15%. Predictive factors for rebound growth included age of discontinuation, deep IH component, and female gender. Patients with these predictive factors may require a prolonged course of therapy.

Sirolimus is safe and efficient for the treatment of BRBNS. Further prospective studies are needed to evaluate the long-term effectiveness of this drug. This is the first report that identifies a lymphatic component as part of BRBNS.

DEAR EDITOR, Infantile haemangiomas (IH) are deep, superficial or mixed vascular neoplasms with rapidly proliferating endothelial cells that stabilize and involute with diminishing cellular activity, apoptosis and resolution over 7-10 years. Clinicians evaluate progression, treatment response and stage by inspection, photography (colour, size, shape) and palpation (temperature, deformability). Lightening, flattening, reduced temperature and softness signal involution. 1 The limitations of subjective methods and need for objective metrics are recognized. 2 Colour, infrared (IR) 3 and three-dimensional (3D) imaging have been applied to IHs. 4 Photographs are compared for improvement as stable/worse (0%), slight (< 25%), moderate (25-50%), good (50-75%) and excellent (> 75%) using the Visual Analog Scale. 5 However, images may be nonstandardized (position, lighting) and results subjective as improvement criteria may be inconsistently applied. 5 IR surface intensity and distribution are affected by tumour depth, size, metabolism, vasculature and perfusion. Dynamic IR applies a temperature stress and the rewarming pattern provides physiological information. 6 We conducted a prospective observational proof of concept study to determine the utility of standardized skin imaging of colour, IR thermography and 3D shape for quantifying IH progression [Clinical Trial Registration: www.clinicaltrials.gov (Identifier NCT02061735)]. We compared these measurements to clinical stage (proliferating, stable, involuting). Data were stratified by age at evaluation, i.e. 1-2, 3-5, 6-9, 10-19 and ≥ 19 months corresponding to expected growth. 7 Fifty-nine patients with 67 superficial or mixed IHs and at least two visits yielded 250 evaluations over 18 months. Deep IHs were excluded due to the small number. Clinicians from our multidisciplinary Hemangioma and Vascular Malformation Center decided the treatment: propranolol (1-2 mg kg À1 daily), topical timolol (one drop 0Á5% gel twice daily) 8 or no treatment, and assessed patients in person. The Institutional Review Board approved the research and parents/guardians provided written informed consent.Standardized colour, IR and 3D images of the IH and contralateral controls were taken (Nikon D90 camera, 60-mm lens, 12Á3 megapixels, cross polarization, wireless flash; Nikon Corporation, Tokyo, Japan; FLIR T400 IR camera; FLIR Inc., Wilsonville, OR, U.S.A.; 3D scanner; Artec MHT, Artec Group,