Dr. Pepe’s Diploma Casebook: CASE 118

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 PA chest radiograph belongs to a 68-year-old woman with sudden onset of chest pain.

What would be your diagnosis?

1. Spontaneous pneumothorax
2. Pneumothorax and cavity in RUL
3. Pneumothorax secondary to pleural metastasis
4. None of the above

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Findings: PA radiograph shows an obvious pneumothorax with a cavity in the RUL (A, arrows). Answer 3 can be excluded because there are no signs suggesting pleural metastasis.

PA radiograph taken four days later after placement of a chest tube.

What would be your diagnosis:

1. Pulmonary bulla
2. Congenital cyst
3. Carcinoma
4. None of the above

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Findings: the pneumothorax has resolved and now a thin-walled cavity is visible in the right upper lobe (B, arrows). It was interpreted as a congenital cyst, and follow-up radiographs were ordered.

Radiographs taken two months later.

What would be your diagnosis?

1. Cavitated carcinoma
2. Pulmonary abscess
3. Tuberculosis
4. None of the above

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Findings: Chest radiographs show a large thick-walled cavity in the RUL (C, arrows). In addition, there is air-space disease affecting the entire RUL, better seen in the lateral view (D, arrows). At this time my preferred diagnosis (against the opinion of several colleagues) was carcinoma because the entire RUL was affected, suggesting a proximal bronchial obstruction.
A chest CT was taken next.

What would be your diagnosis?

1. Carcinoma
2. Abscess
3. Tuberculosis
4. Can’t tell

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Coronal and axial CT confirm the thick-walled mass and involvement of the whole RUL.
The most revealing finding is a narrowing of the proximal RUL bronchus (E-G, red circles), with a thick rim of tissue around it, highly suspicious of a central mass.

Axial and coronal PET/CT confirm high uptake at the proximal RUL bronchus, as well as in the periphery of the cavity (H and I, arrows).
Bronchoscopy confirmed the diagnosis of adenocarcinoma.

The relationship between cystic lesions of the lung and carcinoma is well recognized (see Diploma case 93). In the case presented, the speed of the process is surprising, going from a cystic lesion with thin walls to a full-fledged thick-walled cavity in a period of two months. In my opinion (and I have no proof of this), the cystic lesion is the consequence of central obstruction, leading to the formation of a cavity and subsequent seeding of malignant cells in the wall.

A teaching point is involvement of the entire RUL, well seen in the chest radiograph. Whenever we see complete involvement of a lobe in an adult, we should suspect a central bronchial lesion and look for it in the CT.

An additional teaching point in this case is the normal appearance of the remaining lung, which again favors a stenotic lesion in the proximal RUL bronchus impeding the spread of the cavity contents to the other lobes.

Follow Dr. Pepe’s advice:

1. Isolated cystic airspaces are associated with an increased incidence of carcinomas.

2. Malignancy should be suspected when wall thickening is detected.

3. Involvement of an entire lobe in an adult is suspicious for a central bronchial lesion

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