CASE 12943 Published on 03.12.2015

Cryptogenic organizing “non resolving” pneumonia: a recurrent disease.


Chest imaging

Case Type

Clinical Cases


Parra-Fariñas C, Salcedo MT, Dyer Hartnett S, Comet R.

Department of Radiology.
Vall d´Hebron Hospital. Paseo de la Vall d'Hebron, 119-129, 08035.
Barcelona, Spain.

71 years, female

Area of Interest Thorax, Lung ; Imaging Technique CT-High Resolution, Conventional radiography, Experimental, Percutaneous
Clinical History
A healthy patient presented with a 2-week history of fever, shortness of breath and a non-productive cough. Physical examination revealed crackles over the lower right hemithorax.
Serology for viral agents, blood and sputum cultures, immunological and tumour markers were all within normal range.

The initial treatment was antibiotics for the clinical suspicion of pneumonia, but symptoms persisted.
Imaging Findings
Chest x-ray followed by high resolution computed tomography (HRCT) were performed. The HRCT abnormalities mirror the radiographic appearances showing bilateral patchy consolidations with groundglass opacities, air bronchogram and bronchial dilatations in a peripheral distribution mainly in the right lung (Fig. 1, 2).

Bronchoalveolar lavage specimens were smear and culture negative. Lung biopsy was undertaken showing distal airways filled by fibromyxoid plugs of granulation tissue (Fig. 3).

High doses of oral corticosteroid were commenced with dramatic clinical improvement after 72-hours and near complete resolution of consolidations by the 10th day (Fig. 4).

On follow-up, steroid dose was decreased, but 1 month later, fever recurred and consolidations reappeared (Fig. 5). Steroid dose was increased and complaints disappeared.

Oral corticosteroids were gradually tapered down and the patient was asymptomatic for 4 months. Last HRCT showed an almost complete disappearance of lesions, although ground glass densities still persisted, mainly in the left upper lobe (Fig. 6).
Organizing pneumonia or its idiopathic form, cryptogenic organizing pneumonia (COP) is a clinic-pathologic entity described by Davison and colleagues in 1983 [1]. Organizing pneumonia was formerly known as bronchiolitis obliterans organizing pneumonia (BOOP), a term coined by Epler and co-workers in 1985 [2].

The term COP is preferred because it conveys the essential features of the syndrome [polypoid granulation tissue within alveolar ducts and alveoli with or without organization within bronchioles (“polypoid bronchiolitis obliterans”)] and avoids confusion with airway diseases such as constrictive bronchiolitis obliterans [2-4].

COP is a type of interstitial pulmonary disease included in the classification of the American Thoracic Society and European Respiratory Society statement on the classification of idiopathic interstitial pneumonias (IIP) in the group of major IIP [5].

The true incidence of COP is unknown (1-7/100.000) [6]. Similarly affects men and women in fifth and sixth decade of life [7], mostly in non-smokers.

A short-history (median: <3 months) of dyspnoea, cough and fever is the most common form of presentation [5, 7, 8]. Haemoptysis and pleurisy could be seen too. Because of these symptoms a chest x-ray followed by HRCT are usually the first imaging methods to try to establish the diagnosis. The relatively non-specific radiological findings and the absence of response to traditional treatment lead to additional studies such as bronchoalveolar lavage and open biopsy.

The most important radiological findings are bilateral and asymmetric consolidations commonly associated with ground-glass densities with a peripheral and peribronchovascular distribution, predominating in middle and lower lobes, which may change their location [8-12].

Less frequent manifestations are solitary or multiple nodules or masses [11, 12], reverse (atoll) halo sign [10, 15], thick bands of consolidation extending towards the pleura and crazy-paving pattern [13].

The diagnosis of COP is established by combining clinical, radiological and histological criteria.

Initial therapy depends on severity of symptoms, pulmonary function tests and radiological extension. The majority of patients recover completely with corticosteroid treatment but also relapse. Fibrosis is common with similar findings to those seen in non-specific interstitial pneumonias [5, 13, 14, 16].

COP is a form of IIP that can be easily mistaken for both clinical and radiological lung diseases.
•Non-specific pattern of reparative response of lung to the injury to a non-identifiable cause.
•Should be considered in the differential diagnosis of patients with short-history of breathlessness, cough and fever.
•Typical radiologic manifestations: patchy consolidations and ground-glass opacities that may change their location, resolve without treatment and reappear.
•Fast corticosteroid response with a good prognosis.
Differential Diagnosis List
Cryptogenic organizing pneumonia (COP).
Community acquired pneumonia.
Adenocarcinoma in situ or minimally invasive (bronchoalveolar carcinoma).
Pulmonary lymphoma.
Pulmonary vasculitides.
Chronic eosinophilic pneumonia.
Other idiopathic interstitial pneumonias.
Final Diagnosis
Cryptogenic organizing pneumonia (COP).
Case information
DOI: 10.1594/EURORAD/CASE.12943
ISSN: 1563-4086