Efficacy and safety of sirolimus treatment for intractable lymphatic anomalies: A study protocol for an open-label, single-arm, multicenter, prospective study (SILA)

•This is among the first multicenter studies to evaluate sirolimus for intractable LAs.•The study design is useful for evaluating sirolimus treatment in LAs.•Our study protocol uses novel, uncomplicated methods of radiological assessment.