Spontaneous thoracic duct cyst.

Spontaneous and asymptomatic supraclavicular thoracic duct cysts (lymphoceles ) are rare. Only five cases have been reported so far. They are more common after surgery or trauma and have been reported in the abdomen, mediastinum, pelvis and neck. They must be differentiated from other neck cysts as failure to recognise their attachment may result in the disastrous consequence of chylothorax. A high index of suspicion is necessary, and diagnosis usually can be established by fine-needle aspiration and suitable imaging. This case is reported along with a review of the literature and management options, including that of inadvertent damage to the thoracic duct.