Presenting today a new case of “Big little findings”. This case is not recommended for the faint-hearted 😱
Chest images belong to a 65-year-old woman with moderate cough. Since I am your friend, I am including an axial CT.
What do you think?
Click here to see the answer
Findings: PA radiograph shows a curvilinear opacity in the right middle/lower lung (A, arrows). The right lung is slightly smaller than the left and the hilum looks abnormal (A, circle). Aside from slight elevation of the right hemidiaphragm, the lateral view (B) is unremarkable.
Coronal CT shows that the curvilinear line represents a scimitar vein draining below the diaphragm (C, arrow). The right pulmonary artery describes an unusual path (D, circle) and there is abnormal branching of the right main bronchus (D, circle).
An unexpected finding is an oblique band in the lower right lung (E and F, arrows). The bronchi and RLL vessels pass through an opening in the center (E and F, circles).
Final diagnosis: hypogenetic right lung with duplicated diaphragm
The reason I’m presenting this case is to discuss duplication of the diaphragm, an uncommon congenital malformation associated with hypogenetic lung.
As you all know, hypogenetic lung is a congenital malformation characterized by absence of one or two lobes of the right lung, with abnormal lower lung venous drainage (scimitar vein) in 80% of cases. It is asymptomatic and almost always occurs on the right side. Because it is symptomless, it is usually found incidentally in adults .
Typical signs in the PA chest radiograph (Fig. 1) reflect the small size of the lung:
1. Small right hemithorax with secondary dextrocardia
2. Small right hilum
3. Anomalous vein in RLL (scimitar sign), not always present
Occasionally, hypogenetic lung occurs with minimal hypoplasia, a normal-sized right lung, and absent dextrocardia. In these patients (such as the initial one), the scimitar vein and abnormal right hilum are the clues to the diagnosis.
In my experience, these cases are the ones most commonly associated with duplicated diaphragm, an infrequent malformation resulting from an alteration of caudal migration of the embryonic diaphragm.
Anatomically it appears as a band running obliquely from the chest wall to the right hemidiaphragm (Fig. 3, drawing).
If we’re lucky, we might see it as an oblique line in PA and lateral radiographs (Fig. 4), but it is usually not visible or overlooked (Fig. 5). An additional sign is blurring of the central part of the right hemidiaphragm, where the duplication ends (Figs. 4 and 5).
My hard-learned experience tells me it is very difficult to suspect duplicated diaphragm on plain films. It is usually discovered in a CT performed to confirm a hypogenetic right lung or for other reasons.
The good news is that the CT findings are pathognomonic and consist of:
1. An oblique band with a central opening
2. RLL bronchi and vessels passing through the opening and fanning out thereafter
You may wonder why I present such a rare condition, but the answer is simple:
a) It is easily recognized because of the distinctive findings. Once recognized, advise against surgery or other invasive procedures.
b) I don’t believe it’s that rare. In my career I have seen a dozen cases, the last three in this century and at the same institution. The last, seen in 2015, is the one that headed this Diploma. Two more were seen in 2004 and 2008 (Cases 1 and 2, below).
I am due to see a new case soon. Perhaps in a COVID patient, allowing me to write a useless paper about the relationship between COVID and duplicated diaphragm 🙂
Follow Dr. Pepe’s advice:
1. Duplicated diaphragm is an infrequent malformation associated with hypogenetic right lung
2. Difficult to detect in the chest radiograph
3. Easy to diagnose in CT images by the following signs:
a) Oblique band with a central hiatus in the right lower lung
b) Central hiatus that constricts RLL bronchi and vessels
10 thoughts on “Dr. Pepe’s Diploma Casebook 167 – Big little findings – SOLVED”
Scoliotic thorax cage.
CXR(PA, lateral): Right lower lobe is decreased in volume.
Lung (showned) parenchyma is intact.
There is peribronchovascular thickening at the level of RLL S8-10. As well as thickening of big fissure.
Taking into account both x-ray and ct – suggesting S8 (right) atelectasis.
Suggesting amyloidosis (tracheobronchial type?) DDx lung ca (superficial endobronchial).
Nodulary thickening of the right fissure.
I can see that you are puzzled by this case (only two answers so far). I would offer some tips:
1. Which lung is abnormal, right or left?
2. What do you think of the curve thick line in the middle right lung? What does it look like?
3. The appearance of the CT image is pathognomonic (if you know the entity).
4. Remember that this case is not for the faint-hearted!
1. Right lung is abnormal
2. Looking repeatedly on CXR suggesting vascular (arterial) pathology- right hilum has not its common structure. Thus, this curve thick line could be vessel
3. But I suppose I do not know this entity (maybe, anatomy variation or other benign malignancy)
Don’t worry, you will be able to identify the entity next Friday 🙂
Good! Questions one and two are answered.
What about the CT?
CXR PA , later showed Rticulonoduar shadow bilateral middle and Lowe zones,more right in lung
With obvious loss af right lung volum and thickened curved nodular shadow in middle right lung ? Bronchovascular intesticium thickening,?lymphatic in origin
CT showed thickened blood vessels with mild dilated airways (peribronchovascular interstium thichening),with small nodular lesions petivasular and adhere to pleura near cardiac
Connective tissue disorders (sjogren)
Lymph proliferative disorder
Hello! On Pa image, right hilus with unclear vascular structure. Under it, suspicious nodular opacity. On lateral image, dilated inferior pulmonary veins and arteries. Ct showed a non calcified lobular nodule suspicios with connection to blood vesel (until we have an image of Cy ),and about it, dilated blood veesels. My first opinion is for pulmonary AVM.
This was a difficult case, but I believe an interesting one. Congratulations to Olena and Lczab for their opinions.