Microcystic Lymphatic Malformation Successfully Treated With Topical Rapamycin

Microcystic lymphatic malformations (MLM) are low-flow vascular malformations composed of multiple small cysts. MLM usually affect deep-lying structures, which makes their treatment even more difficult and complex. A novel and interesting treatment is rapamycin, a mammalian target of rapamycin inhibitor that when orally administrated has offered favorable results. However, until recently, topical rapamycin had not been used in the treatment of MLM. Case 1 is a girl aged 13 years with extensive MLM affecting the muscles in the right buttock. The patient had received frequent cycles of cryotherapy, but they had failed to control the associated symptoms. In the previous 12 months, the patient had reported greater discomfort, swelling, exudate, and superinfection of the affected region. Because no specific treatment has yet been approved for MLM, and as a step before the use of aggressive systemic or intralesional treatments, it was decided to initiate treatment with 1% rapamycin ointment. After 4 months of treatment, the patient presented a marked improvement, with a significant reduction of associated complications and no major side effects. Case 2 is a boy aged 5 years who underwent surgery for an intergluteal lipoblastoma at 3 weeks of life and developed a MLM on the scar 6 months afterward. The lesion showed slow growth and continuous exudation with frequent episodes of superinfection. Treatments with laser multiplex and intralesional bleomycin were performed unsuccessfully. In the previous 4 months, the patient had been treated with 1% rapamycin ointment with significant improvement and no side effects.