Case Report: Lymphatic malformation in a paediatric patient with a 7-year follow-Up.

Lymphatic malformations (LMs) are common low-flow vascular anomalies in children. Macrocystic LMs are particularly prone to haemorrhage and may result in life-threatening airway compression. This report describes a 2-month-old female infant with a mixed lymphatic malformation involving the maxillofacial and cervical regions complicated by acute intracystic haemorrhage and severe dyspnoea. Initial management at an external institution simple cyst aspiration without sclerotherapy, which led to rapid disease progression. The patient subsequently underwent emergency sclerotherapy with pingyangmycin (PYM, also known as bleomycin A5) under combined ultrasound and digital subtraction angiography guidance, followed by prolonged oral sirolimus therapy for 2 years. Over a 7-year follow-up period, the lesions demonstrated a durable response without significant recurrence. This case highlights that single session interventional sclerotherapy combined with adjunctive sirolimus therapy can achieve excellent long term outcomes in infants with life-threatening mixed LMs. These findings provide valuable information for the clinical management of this severe condition.