Scimitar variant.

In the classic scimitar syndrome, a pulmonary vein draining all or part of the right lung enters the inferior vena cava. A variant is described with the same roentgenographic appearance, but with drainage of the anomalous pulmonary vein into both the inferior vena cava and the left atrium; the atrial septum was intact. This case, together with six others reported elsewhere, reminds us that the scimitar sign has both false positives and false negatives. Therefore, the diagnosis of scimitar syndrome cannot be made with certainty from a plain x-ray film.