The objective of this study is to report an overlooked cause of cervical swelling linked to a thoracic duct (TD) intraluminal obstruction. Four consecutive patients underwent supraclavicular fossa echo-colour-Doppler assessment (ECD) because of recurrent spontaneous cervical swelling. In all patients, during the swelling period we documented a TD dilation with hyperechogenic content, resulting undetectable during asymptomatic periods; ECD also allowed an effective differential diagnosis with TD cysts, obstructive malignancy or other causes of cervical swelling. In conclusion, ECD is to be considered an effective tool in cervical swelling and TD anomalies investigation.