Dr. Pepe’s Diploma Casebook 170 – SOLVED

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.

There will be no new blog posts over the Easter period. The next case will be published on Monday, April 5, 2021.

The images belong to a 65-year-old woman with cough and low-grade fever. The referred physician demanded a chest CT.

What would be your diagnosis?

1. Pneumonia
2. Pulmonary infarction
3. Peripheral adenocarcinoma
4. Any of the above

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Findings: unenhanced axial and sagittal CTs show LLL airspace disease with a surrounding halo (B-C arrows). In my opinion, the sensible answer is 4. Any of the above, although I liked adenocarcinoma because of the peripheral halo and air bubbles within the infiltrate (A, circle).

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Patient was diagnosed of pneumonia and treated with antibiotics, without improvement. Chest radiographs taken 13 days later shows progression of the LLL opacity (A and B, arrows).

A CT was recommended.

Click here to see the CT images

Two axial and one sagittal views are selected. What would your diagnosis be:

1. Peripheral adenocarcinoma
2. Tuberculosis
3. Covid pneumonia
4. None of the above

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In comparison with the previous CT, the LLL infiltrate has increased markedly in less than two weeks. An upper halo persists (A and C, arrows). A small infiltrate has appeared at the right lung base (B, arrow) In my opinion, this rapid progression rules out carcinoma and TB. A PCR was negative. Blood tests were not remarkable. It was considered that the patient had an unusual pneumonia, and the antibiotic was changed.

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The fever disappeared with the new antibiotic and the patient improved moderately. A new CT was taken three weeks later. What would your diagnosis be?

1. Löffler syndrome
2. Goodpasture syndrome
3. Cryptogenic organizing pneumonia
4. Any of the above

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Findings: The most striking finding is the disappearance of the LLL infiltrate and the apparition of two new areas of airspace disease in RLL and LLL (A, arrows). There is a halo sign in the LUL infiltrate (B, arrows) and a negative halo in the RLL infiltrate (B and C, arrows).
This change of location of the opacities falls in the category of migratory infiltrates which are caused by several diseases, some of them listed in the previous questions.

The patient had no risk factors for parasitic infection and no peripheral eosinophilia, ruling out Löffler syndrome. Renal function was not altered, excluding Goodpasture’s syndrome

The combination of migratory infiltrates and a negative halo sign was very suggestive of a cryptogenetic organizing pneumonia, that was confirmed with BAL and an excellent response to corticosteroid treatment.

Final diagnosis: cryptogenic organizing pneumonia

Organizing pneumonia (OP) is a clinical, radiological and histological entity usually associated to other pathologies. The idiopathic form of OP is called cryptogenic organizing pneumonia (COP).
Clinical manifestations of COP begin with a mild flu-like illness with fever, cough and malaise.
In chest imaging it may appear as localized airspace opacity that may be confused with ordinary pneumonia, adenocarcinoma or aspiration, among others. The lack of response to antibiotic treatment and the peripheral location may help in suggesting the diagnosis.

I am presenting this case because it shows two features the help in the diagnosis: migratory infiltrates and the reverse halo sign.
Migratory infiltrates are not unique to COP, but they occur in a limited number of diseases (Loeffler syndrome, vasculitis, etc.) and their presence in the adequate clinical setting should suggest COP.
The reverse halo was originally described as specific of COP, but since then it has been seen in many other entities. It is defined as a central ground-glass opacity  surrounded by denser consolidation of crescentic shape or a complete ring. It is visible in about 20% of cases.

In this patient the combination of both signs strongly pointed towards COP, that was confirmed and responded brilliantly to corticoid treatment.

To complete the presentation, I am showing two more examples of reversed halo and migratory infiltrates (CASES 1 and 2, below).

CASE 1. 61-year-old woman with COP and basilar infiltrates (A, arrows). During treatment, coronal and axial CTs show bilateral and symmetrical reversed halo signs (B and C, arrows)

CASE 2. 51-year-old woman with COP and migratory pulmonary infiltrates (A and B). The second CT shows nice examples of reversed halo sign (B, circle), better seen in the cone down axial view (C, arrows).

Follow Dr. Pepe’s advice:

1. Localized cryptogenic organizing pneumonia may mimic other pulmonary processes

2. Migrating infiltrates and reverse halo sign (or both) are helpful in suspecting COP

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