Dr. Pepe’s Diploma Casebook: CASE 127

Dear Friends,

This week’s case follows the pattern of a “Meet the Examiner” presentation, with questions and answers similar to a real examination. Take your time before scrolling down for the answer. And no peeking!

The chest radiographs belong to a 64-year-old man with shortness of breath and fever.

What would be your diagnosis?

1. Pulmonary fibrosis
2. Right lung post-TB changes
3. Right main bronchus endobronchial tumor
4. None of the above

Click here for the answer

Findings: There is marked loss of volume of the right lung, with an appearance suggestive of pulmonary fibrosis, causing mediastinal displacement and elevation of the right hemidiaphragm. There is a poorly defined infiltrate at the left base (A, white arrow), and a fracture with callus of the fourth left rib (A, red arrow).

As I mentioned in a previous case (Caceres’ corner 56), this appearance is suggestive of a unilateral left lung transplantation, supported by the postoperative fracture of the left fourth rib. It was confirmed that this particular patient had a left lung transplantation some time ago.

The infiltrate at the left base was interpreted as an acute infection and treated with antibiotics, with a good response.

Control chest radiographs were taken six months later. What would be your diagnosis?

1. Metastatic disease
2. Rib fracture and hematoma
3. Primary carcinoma
4. None of the above

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Six months later the LLL pneumonia has disappeared. There are some fibrous strands in the LUL, unchanged. An extrapulmonary opacity has appeared in the left hemithorax (A, arrow). There is no evidence of rib fracture and malignancy cannot be proven or disproven. CT was carried out.

Click here to see the CT

Enhanced axial CT images at the level of the opacity. What do you think?

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Findings: Axial CT does not show any extrapulmonary lesion. There is widening of the left intercostal space (A, arrow) and the intercostal muscles are absent at the same level (B, arrow) (compare with the opposite side).

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Coronal CT shows slight lung herniation at the intercostal gap (C, arrow). The expiratory chest film shows marked lung herniation at the same level (D, arrow).

Final diagnosis: Postoperative weakness of the left chest wall, leading to medial herniation of the thoracic fat on inspiration and lung herniation on expiration.

This case has two teaching points:

1. When you see a unilaterally diseased small lung and expansion of the opposite one, think of unilateral lung transplantation. Remember that about 4000 lung transplants are performed each year, 1677 of them in the European Union. Familiarity with this appearance (they all look similar, see Caceres’ corner 56) will prevent unnecessary errors.

2. In any operated thorax (transplanted or otherwise), weakening of the chest wall may occur. The consequence may be herniation of the chest wall fat into the lung, simulating an extrapulmonary lesion (see Caceres’ corner 89). The diagnosis is facilitated by noticing the intercostal gap and atrophy of the intercostal muscles in the CT image.

Follow Dr. Pepe’s advice:

1. In a unilaterally diseased small lung think of transplantation (especially if you are taking an examination).

2. Postoperative weakening of the chest wall may result in fat herniation simulating an extrapulmonary lesion.

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