Mediastinal venous anomalies: potential pitfalls in cancer diagnosis.

Mediastinal venous anomalies encountered during CT assessments of cancer patients are often unsuspected and may be misinterpreted, particularly in the presence of intrathoracic disease. Errors in diagnosis result from a lack of intravenous contrast, concomitant mediastinal lymphadenopathy and primary intrathoracic tumour. The small calibre of vessels, previous mediastinal surgery and poor mediastinal planes are other confounding factors. An awareness of the anatomical features and optimal scanning technique are required to avoid misinterpretation.