“…A left-sided supraclavicular cystic mass elicits a wide range of differential diagnoses from branchial cleft cyst, lymphangioma, cystic hygroma, lymphatic malformations, lymphomatous lymph node, cystic lymphadenopathy, nerve sheath tumour, carotid or subclavian artery pseudoaneurysm, cyst from thymus or parathyroid glands, to a sinister lesion such as cystic nodal metastasis (especially level 5B lymph node involvement from papillary thyroid carcinoma and squamous cell carcinoma of the upper aerodigestive tract, and infraclavicular tumours such as pulmonary, abdominal, or pelvic in origin) [2, 3]. Supraclavicular extension of the thoracic duct is quite rare, thus CTDC is not expected to rank high in the list of conditions to consider initially.…”