729 - Treatment Approaches for Microcystic and Mixed Lymphatic Malformations: Current Options and Considerations

Learning Objectives:

• Define microcystic and mixed lymphatic malformations based on imaging


• Describe approaches to treatment for microcystic and mixed lymphatic malformations


• Understand why different approaches are used based on lesion characteristics, location and patient factors

Background: Lymphatic malformations are congenital, low-flow vascular anomalies consisting of dilated lymphatic vasculature. These lymphatic malformations can be split into macrocystic, microcystic or mixed based on imaging parameters. Microcystic lymphatic malformations have cysts with diameters <1 cm and minimally enhance on T2 MRI sequences. Conversely, macrocystic lymphatic malformations have cysts with diameters >1 cm. Mixed lymphatic malformations have cysts of < 1 and >1 cm. Treatment options include surgical resection, topical sirolimus, laser ablation, radio-frequency ablation and sclerotherapy. Sclerosing agents used for lymphatic malformations in general include bleomycin, doxycycline, ethanol and sodium tetradecyl sulfate (STS).

Clinical Findings/Procedure Details: Among microcystic and mixed lymphatic malformations, the most common sclerosing agent used in sclerotherapy is bleomycin. The main side effects of bleomycin include skin discoloration, anaphylaxis and fever. Rarer side effects include potential pulmonary toxicity associated with higher doses, although uncommon in sclerotherapy. Bleomycin tends to be more effective in microcystic lymphatic malformations as it permeates better through the smaller channels compared to agents such as doxycycline or ethanol. Agents such as doxycycline or ethanol require a longer dwelling time for adequate distribution, which can be challenging due to the small cystic spaces. Among cutaneous microcystic and mixed lymphatic malformations, radio-frequency ablation is another effective technique, especially in areas where surgical resection is difficult. Combinations of radiofrequency ablation and sclerotherapy have also been used with success.

Conclusion and/or Teaching Points: Microcystic and mixed lymphatic malformations currently do not have a specific, universally accepted first-line treatment. The use of bleomycin sclerotherapy and radiofrequency ablation are prominent and are tailored to lesion characteristics and patient needs. Future studies comparing efficacy between different approaches are warranted, given the difficulty in treating microcystic malformations.