Dr. Pepe’s Diploma Casebook 166 – Big little findings – SOLVED

Dear friends,

I am starting a new section named “Big little findings”. The aim is to emphasize the importance of discovering subtle findings that should not be missed. They are easily seen if you know what to look for.

Today I’m showing preoperative chest radiographs of a 69-year-old man with bladder carcinoma.

What do you see?

Click here to see the answer

Findings: the most important feature is a negative finding: absence of air in the gastric fornix (A, circle). Although this is sometimes seen in healthy persons, it is more frequent in distal esophageal obstruction. A careful look discovers that the left mediastinum has a double contour, actually the left wall of the dilated esophagus (A, blue arrow) and the descending aorta (A, red arrow). There is bulging of the right paraesophageal line (A, yellow arrow). A dilated air-filled upper esophagus is visible in the lateral view (B, arrows).

The findings are typical of lower esophageal obstruction with dilatation of the esophagus. The double contour of the left mediastinum is better seen in the cone down view (C, arrows) and confirmed with CT (D, arrows).

The air-filled dilated esophagus in the lateral view (E, arrows) is confirmed with sagittal CT (F, arrows) (T= trachea).

Final diagnosis: unsuspected esophageal achalasia

To my eternal shame, I confess that when I read the initial radiographs I overlooked the findings (nobody’s perfect!). Achalasia was discovered in a routine follow-up CT taken one year later. I redeemed myself in a subsequent pre-op PA radiograph of the patient, in which I saw a double contour of the descending aorta (A and B, red and blue arrows) and bulging of the paraesophageal line (A and B, yellow arrows). I missed the absent air in the gastric fornix, again!

Esophageal achalasia is not an uncommon condition, and early stages can be suspected in the chest radiograph if we pay attention to the telltale signs. Note that these signs are not specific for achalasia and can be secondary to any obstructive process of the distal esophagus. The most revealing findings are:

Absent gastric bubble
Displaced lower mediastinal lines
Air-fluid level in the mediastinum


Occurs in about 10% of the normal population and 50% of achalasia patients, and is due to failure of swallowed air to cross the distal esophageal sphincter. It is a negative finding and therefore, difficult to recognize. When it is detected, we should examine the lower mediastinum, looking for signs of esophageal dilatation (Fig. 1).

Fig. 1. 54-year-old man with moderate dysphagia. In the PA radiograph, there is no gastric bubble (do not confuse air in the colon – A and B, black arrows – with air in the gastric fornix). The paraesophageal line is convex (A, red arrow). These two signs are suspicious for achalasia, confirmed with barium swallow. Note the distal esophageal stenosis (B, white arrow).


A dilated esophagus displaces the paraesophageal line toward the right, making it convex. The left wall of the esophagus moves outward, and is sometimes seen as a double contour with the descending aorta (Figs. 2 and 3). Convexity of the paraesophageal line is the most reliable sign and the easiest to detect.

Fig. 2. 48-year-old. woman with achalasia. Initial film shows a normal mediastinum with a visible gastric bubble (A, black arrow). Four years later (B) the gastric bubble is absent. There is a second contour (B, red arrow), paralleling the aorta (B, black arrow). Note that the initial concave paraesophageal line has become straight four years later (A and B, yellow arrows). Esophagogram confirms the esophageal dilatation and the narrow esophagogastric junction (C, red arrow).
Fig. 3. 47-year-old man with dysphagia. PA radiograph shows a convex paraesophageal line (A, white arrow). There is also a convex line on the left (A, red arrow). CT confirms the dilated esophagus containing air and fluid (B and C, asterisks). Diagnosis: esophageal achalasia.


Excluding hiatal hernia, an air-fluid level in the mediastinum is usually located in the esophagus. It is seen as a straight horizontal line in the middle/upper mediastinum. It is usually related to esophageal obstruction of any cause, the most common being achalasia. Discovery of an air-fluid level should lead us to investigate other signs of esophageal dilatation (Figs. 4 and 5).

Fig. 4. 47-year-old woman with dysphagia. PA radiograph shows an air-fluid level in the upper mediastinum (A, red arrow) accompanied by bulging of the paraesophageal line (A, white arrow) and absent gastric fornix. Esophagogram: dilated esophagus with distal stenosis (B, arrow) typical of achalasia.
Fig. 5. Showing this case because it’s a beauty. 73-year-old man referred by the pulmonologist to investigate chronic cough. PA and lateral chest radiographs show a dilated esophagus containing mainly air (A and B, white arrows), with a distal air-fluid level (A and B red arrows). Axial CT confirms the dilated esophagus with retained food (Insert, arrow). Achalasia, confirmed. Air is visible in the gastric fornix in this case (A, black arrow).

Aspiration pneumonia is a complication of achalasia. I’m showing two cases in which the signs mentioned helped to suggest the correct diagnosis (Figs. 6 and 7).


55-year-old man with pancreatic carcinoma and known achalasia who presented with marked cough. Chest radiographs show bilateral airspace infiltrates. In the PA view there is also dilatation of the upper esophagus (A, white arrows) with an air-fluid level (A, red arrow). The lateral view shows a retrocardiac mass (B, white arrow), suggestive of a dilated lower esophagus. The trachea is displaced forward (B, red arrow). These signs were overlooked by the radiologist, whose diagnosis was widespread pneumonia.

Coronal CT demonstrates widespread air-space disease. It also shows a dilated esophagus (C, arrow). Axial CT images confirm dilatation of the esophagus, which is full of residue
(D and E, arrows).
Final diagnosis: esophageal achalasia with secondary aspiration pneumonia.


This an old case of a 27-year-old woman with a chronic RUL opacity suspected to be TB (disregard the opacities in both middle lung fields, caused by superimposed breast implants).
PA chest radiograph shows an opacity in the right upper lobe (A, circle). A right paramediastinal line extends from top to bottom (A, arrows). The lateral view shows anterior displacement of the trachea by a tubular structure (B, arrows), which occupies the upper and middle mediastinum. Both findings suggest a dilated esophagus.
Barium swallow confirms the dilated esophagus, secondary to narrowing at the esophagogastric junction (insert, arrow). Considering the age of the patient, achalasia with aspiration pneumonia was the most likely diagnosis, confirmed later.
(Remember that aspiration pneumonia goes to the right upper lobe when the patient is recumbent at night).

Follow Dr. Pepe’s advice:

Subtle findings of distal esophageal obstruction (achalasia) that should not be overlooked:

1. Absent gastric bubble

2. Displaced lower mediastinal lines

3. Air-fluid level in mediastinum

25 thoughts on “Dr. Pepe’s Diploma Casebook 166 – Big little findings – SOLVED

  1. In my opinion, there are some visible interstitial changes more in the right lung parenchyma, with tiny miliary nodules and more seen in S6 projection on lateral view. DD aging lung

    1. First I also thought about dilatated esophagus but than, in my opinion, I found the line of its posterior wall. So decided – no dilatation.
      What I suggested also – that the walls of esophagus could be thickened.

  2. – lateral shows dilated esophagus
    – absent gastric bubble
    Conclusion: pseudo-/achalasia, needs further evaluation in CT or fluoroscopy with barium swallow

  3. No gastic bubble, the oesophagus is dilated, Naclerio’s V sign on the left side…Boerhave with pneumomediastinum?

  4. Azygoesophageal line looks more or less normal. Posterior junction line (or is it the left paraspinal line?) seems to be thickened. Slightly thickened retrotracheal stripe on the lateral view.

  5. There appears linear retro cardiac density with lateral displacement of left paraspinal line.Differential includes any pathology related to descending aorta.In this particular case, May be any complications related to intravesical BCG therapy.

  6. ….Gentilie PROF….. a me sembra di vedere , in AP, a dx, a livello paramediastinico alto, un sottile tubicino, rx’opaco, che potrebbe essere un pezzo di catetere venoso migrato dalla sue sede originaria….

  7. Good morning!!!

    Double line in the left paraspinal area (one is the descending aorta). In the lateral x-ray there is anythig wrong. A would recommend a CT-scan

  8. Given the hint of a certain abnormality on the lateral view…
    a. There is an oblique line crossing the posterior elements of an upper thoracic vertebra which may correspond to the finding mentioned by the Italian colleague.
    b. I see an oval lucency superimposed between the left pulmonary artery and the aorta which could be a posteriorly displaced bronchus.

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