Dr. Pepe’s Diploma Casebook: CASE 124 – SOLVED!

Findings: PA radiograph shows an enlarged left hilum (A, white arrow) and blurring of the left heart border (A, red arrow). Lateral view shows a retro-sternal line (B, arrows), which represents the displaced major fissure. The findings are highly suspicious of severe LUL collapse.

Unenhanced coronal and axial CT confirm the marked LUL collapse (C and D, white arrows), due to bronchial narrowing (D, red arrow).

Review of a routine CT examination made one year earlier shows moderate loss of volume of LUL (E and F, white arrows), and a mass in the LUL bronchus that was overlooked (F, red arrow).

Final diagnosis: primary bronchogenic carcinoma with marked LUL collapse

I am presenting this case to review the most common forms of presentation of lung carcinoma and how to recognize them. Around 50% of lung carcinomas appear as central lesions and 30% as peripheral lesions.

Today I would like to discuss central carcinomas. They occlude those affecting a main bronchus, resulting in lung/lobar collapse. Recognizing the typical findings of lung/lobar collapse is reasonably easy and has been discussed in Diploma case 16, Diploma case 40, Diploma case 58, Diploma case 63, Diploma case 79, and Diploma case 87.

In this presentation, I would like to share with you a few useful tips to suspect malignant lobar collapse when the manifestations are not typical.

Just to refresh our knowledge, remember that the typical signs of a collapsed lobe are increased opacity of the lobe and retraction of neighboring structures, mainly the fissures and the hila (Fig. 1).

Enhanced axial and coronal CT images in the second patient show that the triangular opacity corresponds to extrapulmonary fat simulating a collapsed lobe (C and D, white arrows). Note the tracheal displacement (C and D, red arrows). The lack of hilar retraction in the plain film is the clue to a correct interpretation.

Tip #1. Suspect a central lesion in any adult with involvement of an entire lobe. Of course, lobar pneumonias occur, but less commonly than is thought. And always follow a lobar pneumonia until it is completely resolved (Figs. 2 and 3)

Coronal and axial CT confirm the cavity and involvement of the whole lobe. There is marked narrowing of the RUL bronchus (C and D, arrows). PET-CT shows marked uptake at the origin of the RUL bronchus and in the cavity wall (E, arrows).

Diagnosis: carcinoma

Axial and coronal CT images confirm a marked narrowing of the RUL bronchus (E and F, red arrows), and involvement of the anterior and posterior segments (F, white arrows). Bronchoscopy confirmed a central carcinoma.

Tip #2. In any pulmonary infiltrate, always look for hilar/fissure displacement. These two signs, together or alone, are very useful markers of loss of volume of a lobe and raise the suspicion of a central lesion (Figs. 4-6).

Fig. 4. 57-year-old woman with chronic cough. PA radiograph shows an ill-defined retrocardiac infiltrate (A, black arrow). The left hilum is descended and hidden behind the cardiac silhouette (A, red arrow). The lateral view shows only slight blurring of the left hemidiaphragm (B, arrow).

Coronal CT confirms the marked LLL volume loss and bronchiectasis (C, arrow). A ventral slice shows a calcified endobronchial mass as the cause of the collapse and bronchiectasis (D, arrow). Final diagnosis: endobronchial carcinoid tumor

Fig. 5. 58-year-old man with cough. PA radiograph shows a markedly descended left hilum (A, red arrow). There is a left paramediastinal curved line, which represents the major fissure (A, white arrows). Coronal CT shows a mass and narrowing at the origin of the LLL bronchus (B, arrow). Axial CT confirms the severe LLL volume loss (insert, arrow). Bronchoscopy confirmed a central carcinoma.

Fig. 6. Aerated RLL collapse in carcinoma. PA chest film depicts a right hilar mass with descended hilum (A and B, red arrows). The descended major fissure is barely visible (A, white arrow). In the lateral view, the collapsed lobe is seen as a faint opacity projected over the spine (B, white arrow). Bronchoscopy confirmed carcinoma.

Tip #3. Always look at the lateral radiograph for help. Remember that collapse of the LUL or RML usually gives inconclusive findings in the PA view, and is better depicted in the lateral projection (Fig. 7). In particular, RML collapse can be almost invisible in the PA view, only suspected because of some blurring of the right heart border (Fig. 8).

Fig. 7. PA radiograph shows ill-defined opacification of left lung accompanied by pleural fluid (A, arrow). Lateral view demonstrates the typical findings of LUL collapse: retrosternal opacification and displaced major fissure (B, arrows). Axial CT confirms the collapse (insert, white arrow) and bronchial obstruction secondary to a central carcinoma (insert, red arrow).

Fig. 8. Chronic RML collapse, visible only in the PA view as slight blurring of the right heart border (A, arrow). The lateral view confirms the marked RML collapse (B, arrow).

Tip #4. Recognizing mucus impaction is a useful hint to suspect central carcinoma. Although mucus impaction may have other etiologies, the prevalence of bronchogenic carcinoma makes it the most common cause in clinical practice (Figs. 9-10).

Fig. 9. 64-year-old man with persistent cough and weight loss. PA and lateral radiographs show elongated opacities arising from the hilum, reminiscent of mucus impaction (A and B, arrows).

Coronal and axial enhanced CT show an obvious mucus impaction in the RUL (C and D, white arrows) caused by an endobronchial lesion protruding into the lumen of the intermediate bronchus (C, red arrow). PET-CT shows marked uptake of the lesion (E, arrow) Diagnosis: carcinoma

Fig. 10. 56-year-old patient with carcinoma, visible as a mass in the right hilum (A, white arrow) Mucus impaction is present (A, red arrow). Enhanced coronal CT confirms the hilar mass (B, asterisk) as well as the mucus impactions (B, arrows), which are easily distinguished from the enhanced vessels.

Follow Dr. Pepe’s advice:

To exclude a central lesion:

1. Suspect a central lesion in any adult with involvement of an entire lobe.

2. Always look for hilar/fissure displacement in any pulmonary infiltrate.

3. Always look at the lateral radiograph for help.

4. Recognizing mucus impaction is a useful hint to suspect central carcinoma.