This case appears to be a classic Scimitar Syndrome, with the heart dispaced to the right and the scimitar veins seen at the right base heading down towards the right diaphragm. However you must not make a confident diagnosis, as all is not what it seems. There is actually a clue in that the "scimitar veins" are multiple, which is quite unusual for true Scimitar Syndrome.
Here are delayed images from the left ventricular angiogram in this case. On the left is the arterial phase, showing that the "veins" at the right base are in fact arterial collaterals from the abdomen ( there was no right pulmonary artery). On the right is the pulmonary venous phase with the right veins draining to the left atrium. So although the hypoplasia of the right lung seemed typical, the vascular abnormalities do not allow this to be called a Scimitar Syndrome. You could call it a variant, but I much prefer another term, see below.
I like the term "dysmorphic lung" for this group, as all parts of the small right lung show disordered development. A regular feature is failure of the lung to divide into lobes: the bronchial branching pattern, and (as above) the arterial branching pattern are far from normal.(Scimitar etcetera- the dysmorphic right lung. Partridge JB, Osborne JM, Slaughter RE. Clinical Radiology 1988;39:11-20.)
I will now briefly review the embryology of the pulmonary arteries, as it has relevence in a number of situations.
Above is the general plan of the six arches of the template of the embroynic arterial system. They persist in the fish as the supply to the gill clefts. As you will know, the trachea, bronchi and lungs are formed as a division of the foregut. The lung buds, here in blue, need to connect with the sixth aortic arch which is to become the central pulmonary arterial system. To do this, each lung bud sends a unified artery into the mediastinum to seek out the sixth arch components.
And here they have achieved their goal. I have set this against the Edwards diagram (Jesse Edwards, one of the "names" in cardiac morphology) which you should regognise as the template for all the arch malformations.
Later, the embryonic double arch system looses its rightward limb. The remnant of the left sixth arch beyond the attachment of the left pulmonary artery persists as the arterial duct (arrowed).
However, there is a big problem with this type of diagram. Looking at it you would be forgiven to think that the old sixth aortic arch extends out to form the hilar pulmonary arteries. This is not so.
This is much more the situation. The position of the ductal ligament (here in green) must mark the end of the sixth arch component on the left, and as you will know it is attached very close to the bifurcation of the main pulmonary artery. The situation must be similar on the right side, though there is no ductus. So, it follows that the sixth aortic arch contributes the main pulmonary artery and only the very origins of the branch pulmonary arteries. The hilar arteries come from the lung buds themselves. Above, the demarcation between the two is the dotted lines. Four inferences follow:-
First, tetralogy of Fallot. Here is a frontal angiogram of the right ventricular outflow. In tetralogy, the essential abnormality is hypoplasia of the sixth aortic arch and the RV infundibulum. You will see that the main PA and its proximal branches are small, whereas the hilar arteries, which are derived from the lung bud vessels, are of more normal size. (in this case there is even some post-stenotic dilatation of the upper branch of the RPA). This combination is seen in about half of cases, and occasionally the narrowing of the origin of the branch vessels is severe. In cases where pulmonary blood flow is more chronically diminished, the hilar arteries can also be small.
Secondly, right pulmonary artery atresia. An uncommon pathology, it should really be called "interrupted RPA", because it is really a failure of the incoming right lung bud to locate the sixth aortic arch. Instead, the lung bud artery stays attached to the right arterial duct, which arises from the innominate artery if there is a left aortic arch. In this case, a wedged right pulmonary vein angiogram has filled the isolated distal RPA and its branches, which show normal morphology. Usually the right arterial duct will have closed, but if presentation is in the neonatal period the duct may still be patent. So, if RPA "atresia" is diagnosed, it is worth looking for the distal vessel and surgical reconnection can be considered if it is present. This is mostly the case in the younger child: later in life I suspect the RPA atrophies, or at least fails to grow, and is not big enough to correct.
Thirdly, the left pulmonary artery sling. This is nicely seen in this cranially angulated frontal right ventriculogram in a neonate. Why should the left pulmonary artery pass between the trachea and oesophagus and make such a tight sling aound the airways? Stridor is the usual presentation. Well, the embryology helps. Having for some reason failed to find the sixth arch structures anteriorly, the left lung bud artery has burrowed across the midline and turned anteriorly. However, in front of it is the other lung bud artery, which is not its target. Presumably it can sense the MPA to the left, and so it makes this tight turn to the left and snares the lower trachea in the process.
It is interesting to reflect that RPA "atresia" is usually seen as an isolated pathology. LPA atresia is seen but only as a complication of tetralogy of Fallot. Perhaps LPA sling is the corresponding isolated connection problem. I have never seen a RPA sling, a prize for the first one!
And lastly, the MAPCA ("major aorto pulmonary collateral artery"). Not to be confused with secondary dilatation of the bronchial arteries, these collaterals occur in Fallot type pulmonary atresia and occasionally in other pathologies, mainly ordinary tetralogies. They usually arise from the descending aorta but may come from any thoracic, proximal brachial or upper abdominal artery. This image is of one from the mid descending aorta, where it has been selectively injected. It shows that the parenchymal vessels supplied look like perfectly normal pulmonary arteries, and so they are. They are a section of normal lung which, trying to find central sixth arch structures which are absent or at the best severely hypoplastic, have enforced an origin from the nearby aorta. It is not surprising that this unwanted connection is stenosed. In this illustration I have put a dotted line across where I think the lung bud has met the abnormal systemic artery. I think it is important to realise that these collaterals have "taken out" the native distal vessels and the lung supplied has no other route of perfusion apart from the bronchials. There may be a more normal pulmonary arterial sysem elsewhere in the lungs, which may be encouraged to grow, but it will not give good supply to the collaterallised area. No wonder that surgery for this condition can often be a disappointment.