Abstract Number ‐ 47: Adult and Pediatric Facial Droop in Facial Lymphatic Malformations: Causes and Resolution
Authors: Bazil Maximilian J , Scaggiante Jacopo , Bonet Jessica , Shigematsu Tomoyoshi , Fifi Johanna T , Berenstein Alejandro 
Published: April 2023

Introduction
Facial Lymphatic Malformations (LMs) are low‐flow, infiltrative vascular lesions which are typically treated with sclerotherapeutic agents or, in refractive/aggressive cases, surgical resection. In our practice, we have found a subset of these patients present with or develop a facial droop over the course of their treatment.(1) The development, persistence, or abation of this facial droop is a crucial component of facial LM “cure” considering the long‐term burden patients carry if it persists. The likely causes and frequency of resolution are described.

Methods
A retrospective review of our institutional, quality‐control database was performed to identify all consecutive cases of facial LMs or LMs with facial components between January 1996 and July 2022. Cases were selected for detailed review if a facial droop was identified in photographs over the course of their treatment and if radiographic imaging was available for review.

Results
A total of 152 patients with facial LMs or facial components of an LM were selected for initial screening with 110 (72.4%) pediatrics (average age = 5.3+/‐4.6 years) and 42 (27.6%) adults (average age = 34.0+/‐16.0 years) at first treatment for the LM. Among these 152, 36 (23.7%) facial droops were identified of which 31 pediatric patients (86.1% of facial droops; 28% of pediatrics overall) and 5 adults (13.9% of facial droops; 11.9% of adults). 13 (40.6%) patients experiened facial droop abation overall with 10 pediatrics (76.9% of abated, 32% of peds) and 3 adults (23.1% of abated, 60% of adults). Overall, LMs were distributed across 2 (6%) macrocystics, 18 (50%) microcystics, and 16 (44%) mixed lesions. Only 21 cases with facial droops were eligible for the final stage of analysis due to insufficient pre‐operative ragiographic imaging in the excluded 15. Facial nerve involvement alone was identified in 4/21 (19%) cases, muscle damage in 3/21 (14%), 6/21 (29%) with both, and 7/21 (33%) with neither. Resolution was assessed by comparison of pre and post‐treatment imaging with a minimum follow‐up time of 6 months and a maximum of over 11 years.Resolution occurred in 50% of cases involving the facial nerve alone, 100% of cases involving muscle damage alone, and 33% in cases involving both. In cases where facial droop was unattributable to either facial nerve involvement or muscle damage, only 1/7 (14%) facial droops resolved.

Conclusions
Facial LMs may lead to development of a facial droop as early as initial presentation or during treatment and persist without abation. The majority of LM cases which developed facial droop in this series were microcystic or had a microcystic component (mixed). Facial nerve damage, muscle damage, or both were designated as the cause of the facial droop in 66% of cases. It is unknown what may have led to the droopage in the remaining 33% of cases. Muscle damage alone resulted in the highest rate of resolution across the study period.