CPT code 38555 designates the surgical excision of a cystic hygroma located deep in the armpit or neck, a procedure that frequently requires meticulous dissection around critical nerves and blood vessels. Nationally, this code captures a specialized head, neck and axillary surgical service performed in the operating room or ambulatory surgical center and is relevant to surgical, otolaryngology, and pediatric surgical practices managing congenital lymphatic malformations. Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for CPT code 38555, typical settings of care, common modifiers used with surgical procedures, and the payer mix addressed in this publication. The content highlights billing and coding clarity for encounters involving deep excision of cystic hygromas, and provides national-level context for reimbursement benchmarking and policy review where available. Data not available in the input is noted where specific payer policies, ICD-10 mappings, and related codes would normally be detailed.