Dr. Pepe’s Diploma Casebook: Case 117 – SOLVED!

Dear Friends,

To start the new year and the new website I am presenting radiographs of a 60-year-old man with dyspnea.

Diagnosis:

1. Congenital lung hypoplasia
2. Previous surgery
3. Previous TB
4. Any of the above

Check the images below, leave your thoughts in the comments section, and come back on Friday for the answer.


Click here for the answer

Findings: PA radiograph shows a small right hemithorax with loss of volume and increased opacity of the right lung. The mediastinum is shifted towards the right (A, arrow) and there is elevation of the right hemidiaphragm, which is blurred in the lateral view (B, arrows).

Coronal CT confirms the right lung involvement and marked mediastinal shift (C, arrow). The patient had end-stage lung disease secondary to NSIP and had undergone a lung transplantation. MIP coronal reconstruction shows the area of suture of the left bronchus (D, arrow).

Final diagnosis: Small right lung due to NSIP. Transplanted left lung

I am presenting this case to discuss the small hemithorax, which is easily recognized because of its reduced size in comparison to the opposite side. Small hemithorax often shows partial or complete opacification of the underlying lung, pleural thickening, and crowding of the ribs.
The etiology of small hemithorax may be a pulmonary or pleural disease.

Lung-related causes of small hemithorax can be congenital or acquired. Among the congenital causes, the most frequent is hypoplasia/aplasia of the lung and bronchial tree (Fig. 1). Much less common is congenital unilateral absence of the pulmonary artery or pulmonary veins (Fig. 2).

Fig. 1. 27-year-old asymptomatic man with a hypogenetic right lung. PA radiograph shows a small right hemithorax with mediastinal shift and blurring of the right heart border (A, asterisk). There is a scimitar vein (A, arrow), confirmed with coronal CT (B, arrow).
Fig. 2. 47-year-old man with left main pulmonary artery agenesis . Note the small left hemithorax with mediastinal shift (A, arrow) and poor vascularization of the left lung. Coronal CT confirms the absence of the left main pulmonary artery (B, arrow).

Acquired causes of small hemithorax can be obstruction of the main bronchus of any etiology (Fig. 3) (malignant endobronchial tumor being the most common), or a chronic pulmonary infection, with lung destruction and volume loss (most commonly due to TB) (Fig. 4).

Fig. 3. 65-year-old woman with sudden dyspnea. PA radiograph on admission shows complete opacification of the left lung and cut-off of the left main bronchus (A, yellow arrow). There is marked elevation of the left hemidiaphragm, as indicated by the raised gastric bubble (A and B, red arrow).

Coronal CT confirms the left lung volume loss and the endobronchial lesion (C, arrow). Bronchoscopy extracted thick mucus from the left main bronchus. A post-procedure radiograph shows re-expansion of most of the left lung with residual LUL collapse (D, arrow). Diagnosis: allergic aspergillosis

Fig. 4. Two different patients with previous TB showing a small left hemithorax with crowding of the ribs and shifted mediastinum (A and B, arrows). Lung scarring is also seen.

Pleural disease may cause small hemithorax by creating a thick cuirass that impedes expansion of the lung and decreases the size of the affected hemithorax. Most causes of benign pleural thickening result from empyema or a hemothorax, which often become calcified (Fig. 5).

Fig. 5. Two different patients with healed pleural TB. The first one has a small hemithorax with pleural thickening and calcification (A, arrows), and mediastinal shift. In the second patient, the pleural thickening is limited to the apex (B, arrow), but the calcification is obvious.

Malignant pleural mesothelioma may grow in a plaque-like manner and encase the lung, causing a decrease in size of the hemithorax (Fig. 6). Metastasis to the pleura can give a similar appearance (Fig. 7).

Fig. 6. 73-year-old man with asbestos-related mesothelioma. PA radiograph shows a small right hemithorax with pleural masses (A, white arrow). Pleural plaques are visible (A, red arrows). There is destruction of the anterior third rib (A, yellow arrow). Axial CT confirms the pleural mass, bilateral calcified plaques (B, red arrows), and rib destruction (B, yellow arrow).
Fig. 7. 62-year-old man with pleural metastasis causing pleural thickening and small hemithorax (A, arrows), confirmed with coronal CT (B, arrows). The radiologic appearance cannot be distinguished from malignant mesothelioma or lymphoma.

Last, but not least, we have to consider previous surgery as the cause of small hemithorax. The most frequent etiology is lung resection (Fig. 8), but a rib cage intervention should also be considered (Fig. 9).

Fig. 8. 22-year-old woman after resection of a mediastinal sarcoma and partial left lung resection. Note the small left hemithorax with mediastinal shift and crowding of the ribs (A, arrow), confirmed with coronal CT (B, arrow).

Thoracoplasty is an old procedure, mainly used in the pre-antibiotic era to collapse tuberculous cavities. We still see some of these patients (Fig. 9).

Fig. 9. Two patients who underwent thoracoplasty. Note the marked deformity of the affected hemithorax and calcification of the underlying pleura (A and B, arrows).


Follow Dr. Pepe’s advice:

1. Congenital small hemithorax is usually due to hypoplasia of the lung.

2. The most common cause of acquired small hemithorax is an endobronchial lesion.

3. Chronic pleural disease is not an uncommon cause of small hemithorax.

9 thoughts on “Dr. Pepe’s Diploma Casebook: Case 117 – SOLVED!

  1. First I thought it was left lung transplant, but I see no traces of surgery. Then I’ll go for no. 4., but I think that congenital lung hypoplasia is least likely.

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  2. It could be previous tuberculosis ( No. 3).
    As Right thorax is opaque and mediastinum is shifted towards right side , could be fibrothorax which is late complication of T.B.

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  3. Tiene pérdida del volumen del pulmón derecho, con un parénquima de aspecto fibrótico. Y desviación del mediastino hacia la derecha (por esto descarto hipoplasia congénita). No veo suturas metálicas que sugieran antecedentes quirúrgicos. Impresiona neumotórax derecho.
    Pienso que es una fibrosis pulmonar asociada a neumotórax espontáneo sugestivo de tuberculosis. Respuesta: 3 tuberculosis.

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    1. La hipoplasia pulmonar puede ocurrir en ambos lados y el aspecto puede ser similar al de la radiografía. En mi opinión, no puede descartarse, aunque no es el diagnóstico en este caso.
      Gracias por participar.

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  4. Thanks to you all for participating in the new blog. Will give the first prize to Samreen although, in my opinion, it is difficult to opt among the three options without TC (or clinical history)

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  5. Difficult to differentiate between TB and previous surgery on film , If this x ray is in developing countries then TB is the right answer and in developed countries it will be prevoius lung surgery..

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