Incidence and Factors Associated With Spontaneous Regression in Head and Neck Lymphatic Malformations

Head and neck lymphatic malformations (HNLMs) demonstrate considerable variability in their natural history. While some malformations cause chronic severe functional impairment, others are asymptomatic and spontaneously regress. Understanding the frequency and features associated with regression will aid clinicians and families in making informed treatment choices and avoid unnecessary risks of intervention for a subset of patients.

To assess the incidence, timing, and factors associated with spontaneous regression of HNLMs.

This retrospective cohort study across a single regional pediatric tertiary care academic center included patients aged 0 to 21 years with HNLM who were evaluated in the vascular anomalies clinic and prospectively enrolled in an institutional quality improvement database between 2003 and 2022. Observation was offered to patients without symptoms or functional compromise. Treatment decisions were made during routine clinical care.

Age of HNLM onset and HNLM location, distribution, cystic structure, grade, and de Serres staging.

The incidence of complete spontaneous regression was estimated. The strength of the association between exposures and regression was assessed using risk ratios, Cliff Δ, and Cramer V. A Kaplan-Meier curve was used to estimate the probability of spontaneous regression over time. The association of the exposures on the likelihood of spontaneous regression were assessed using 2-sided log-rank tests and Cox proportional hazards models.

Of 298 patients with HNLMs, 173 (58.1%) were male, and most HNLMs were diagnosed prenatally or at birth (137 patients [46.0%]). Among HNLMs, 189 (63.4%) had a focal distribution, 228 (76.5%) were de Serres stage I or II, and 128 (43.0%) were macrocystic. Complete spontaneous regression occurred in 27 patients (9.1%) at a median (IQR) time of 12.0 (6.7-27.4) months from onset. Factors associated with a large difference in the rate of complete spontaneous regression included macrocystic structure, neck location, focal distribution, and grade 1 or de Serres I stage. HNLMs of the upper face or midface, with mixed or microcystic composition, or with extensive unilateral or bilateral involvement did not regress.

In this cohort study, HNLMs that were macrocystic, of limited extent, and/or in the neck were more likely to completely spontaneously regress. A 1-year observation period for asymptomatic HNLM, particularly when favorable features are present, should be considered, as nonintervention may be curative. Future studies will examine interaction among these factors. This work contributes to a deeper understanding of HNLM natural history that can directly inform clinical decision-making, decrease treatment risk, and optimize patient outcomes.