CASE 13414 Published on 27.03.2016

A case of COP misdiagnosed as cannon ball pulmonary metastasis on the basis of radiological appearance


Chest imaging

Case Type

Clinical Cases


Waseem Mehmood Nizamani, Fatima Mubarak

Aga Khan University Hospital,
Stadium Rd,
Karachi 74800

51 years, female

Area of Interest Lung ; Imaging Technique CT, Conventional radiography
Clinical History
51-year-old female presented with fever and shortness of breath. Haematological work up shows raised total leukocyte count (TLC) of 14.9. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were 17.39 mg/dl and 38 mm/1st hour respectively. All other lab tests were normal.
Imaging Findings
The chest radiograph shows multiple large rounded soft tissue density masses/nodules scattered in both lungs. (Fig. 2a) Computed Tomography (CT) was advised for further workup. CT chest showed multiple rounded variable-sized soft tissue density lesions scattered in bilateral lungs fields, few of these were showing central low attenuation. The largest one in the left lung apex appeared more solid showing spiculated margins. Multiple enlarged mediastinal lymph nodes at right paratracheal, subcarinal and prevascular location. No evidence of peripheral consolidation on either side. No evidence of pleural effusion or pneumothorax bilaterally. (Fig. 1)
Multinodular disease of the lung is a common characteristic of metastatic lung disease, associated in particular with renal, breast, thyroid and gastrointestinal tract malignancies. Numerous non-malignant diseases may also present with a similar radiological picture such as cryptogenic organizing pneumonia (COP), tuberculosis, aspergillosis and Wegener's granulomatosis. [1] Researchers have tried to reach a specific diagnosis based on morphological characteristics and anatomic localization of the nodules using HRCT of lung but definite diagnosis always requires biopsy. [2] This patient was initially diagnosed as a case of pulmonary metastasis on radiological appearance. On the basis of the findings, the patient underwent an extensive investigation attempting to locate a primary tumour. After an unsuccessful workup, the patient was referred for biopsy, which revealed features of organizing pneumonia without any evidence of malignancy.
Cryptogenic organizing pneumonia (COP) is a pulmonary disorder characterized by plugs of granulation tissue in bronchioles, alveolar ducts and alveoli. It may be cryptogenic or may be associated with viral infection, toxic fume inhalation, connective tissue disease, drug administration, bone marrow and heart-lung transplantation. [3] On High resolution CT (HRCT) usual features of COP are patchy consolidation with a predominantly subpleural and/or peribronchial distribution. Large pulmonary nodules/masses are found to be rare CT features of COP. This case illustrates that the clinical, roentgenographic, and CT findings of COP are nonspecific and in some cases can be confused with those of metastatic tumour in the lungs. The clinical symptoms and pulmonary lesions dramatically resolved as the patient received steroid therapy. Follow-up radiograph revealed residual fibrosis without lung nodules. Whatever the aetiology, early diagnosis may have prevented the patient from having rapidly progressive COP that is a deadly form of the disease and can occur in a small percentage of patients. [4] In conclusion, not every patient showing cannonball lesions in lung should be directly labelled as a case of disseminated malignancy and timely image-guided biopsy can prevent unnecessary delay in diagnosis and management.
Differential Diagnosis List
Cryptogenic organizing pneumonia (COP)
Pulmonary metastasis
Wegeners granulomatosis
Final Diagnosis
Cryptogenic organizing pneumonia (COP)
Case information
DOI: 10.1594/EURORAD/CASE.13414
ISSN: 1563-4086