High-Frequency Ultrasound-Guided Treatment of a Head and Neck Lymphatic Malformation

Lymphatic malformations (LMs) are rare congenital low-flow vascular anomalies that frequently involve the head and neck and may be managed with surgery, laser therapy, sclerotherapy, or multimodal approaches depending on lesion type, size, depth, and relationship with adjacent structures. Ultrasound-guided sclerotherapy with doxycycline is an established treatment option for macrocystic lesions, whereas the practical role of high-frequency superficial ultrasound as a technical adjunct has been less specifically discussed. We report the case of a 32-year-old man presenting with a painless left submandibular swelling of approximately two years' duration. Magnetic resonance imaging showed a well-encapsulated cystic lesion measuring 56 × 35 mm in the left submandibular region, extending into the internal paralaryngeal space and causing mild compression of the laryngeal wall. Previous fine-needle aspiration cytology had not conclusively established the lymphatic nature of the lesion; therefore, an incisional biopsy was performed and confirmed a macrocystic LM. The patient underwent day-surgery intralesional doxycycline sclerotherapy under real-time high-frequency ultrasound guidance using an 18 MHz hockey-stick transducer. After aspiration of the main cystic compartment through a 25-gauge needle, 100 mg of doxycycline diluted to 10 mg/mL in normal saline was slowly injected under continuous visualization. The procedure was well tolerated under topical local anesthesia, without pain, complications, or adverse effects. A partial clinical reduction was observed after the first session; the treatment was repeated after three months, resulting in apparent complete clinical resolution at one-year follow-up; no post-treatment imaging was available to confirm radiological resolution. This case highlights the potential technical value of high-frequency superficial ultrasonography, particularly for needle positioning, improved delineation of superficial locules, and real-time monitoring of sclerosant distribution.