Abstract
A very rare case of a rapidly progressive variant of cryptogenic organising pneumonia (COP) presenting as a focal mass-like lesion with compression of the large airways leading to respiratory failure is described. A 60-year-old lady presented to the Aga Khan University Hospital Emergency Department in hypoxaemic respiratory failure with a 6-day history of dyspnoea, productive cough and fever. Chest x ray showed a right upper lobe mass-like lesion compressing the large airways and right pleural effusion. She deteriorated in the Emergency Department and was intubated due to worsening hypoxaemic respiratory failure. The pleural fluid and bronchoscopic specimens were negative on microbiological and cytological examination. CT-guided right lung biopsy revealed chronic non-specific inflammation without granuloma and malignancy. COP was diagnosed on video-assisted thoracoscopic (VATS) lung biopsy. She was successfully treated with high dose steroids and discharged in a stable condition; her 3-month follow-up chest x rays showed complete resolution of the lung lesion with some residual fibrosis.
BACKGROUND
Rapidly progressive cryptogenic organising pneumonia (COP) can occur in a small percentage of patients, but it is a deadly form of the disease.1 This form of COP occurs equally in men and women and at all ages. It can occur in healthy, vigorous individuals or can be associated with other systemic disorders. The course can be rapid, with 1–3 days of symptoms and acute respiratory failure. Patients might present with symptoms similar to adult respiratory distress syndrome or acute interstitial pneumonia.2
A focal nodular presentation of COP has been reported in the literature. In that case it might be indistinguishable from carcinoma of the lung.3 However, presentation of a rapidly progressive variant as a focal lung lesion is very rare. This highlights the importance of this rare case and the fact that COP should be considered in the differential diagnosis of focal lung lesion as appropriate treatment, if instituted early, can result in improved survival.
CASE PRESENTATION
A 60-year-old female presented to the Emergency Department with a 6-day history of dyspnoea accompanied by productive cough and fever. She is a non-smoker with a history of hypertension and spinal tuberculosis, received antituberculous drugs 3 years previously and recovered completly. She has no other significant medical or surgical history.
On arrival in the Emergency Department she was tachypnoeic and tachycardic with a temperature of 37.7°C. Chest auscultation revealed a few crackles in the right upper chest and decreased breath sound at the right base. The remainder of the clinical examination was unremarkable. She deteriorated in the Emergency Department, maintaining an SaO2 (arterial oxygen saturation) of 83.5% on a 15 litre face mask, and had to be intubated due to worsening hypoxaemic respiratory failure.
She was started on intravenous ceftriaxone and levofloxacin. Right diagnostic thoracentesis showed an exudative lymphocytic pleural effusion. The pleural fluid and bronchoscopic specimens were negative on microbiological and cytological examination. The endobronchial biopsy revealed chronic inflammation. CT-guided right lung biopsy was carried out and revealed fibrosis with mild chronic non-specific inflammation without granuloma and malignancy. The ceftriaxone was replaced by intravenous piperacillin–tazobactam. Video-assisted thoracoscopic (VATS) lung biopsy was performed to obtain the diagnosis on the 10th day of admission. Histopathology revealed changes consistent with later stages of organised pneumonia.
She was pulsed with intravenous methylprednisolone for 5 days. The patient’s condition started to improve and she was extubated after a few days. Methylprednisolone was changed to oral prednisolone that was tapered gradually in subsequent outpatient visits.
INVESTIGATIONS
Diagnostic laboratory tests done on arrival revealed an elevated white blood cell (WBC) count of 16.6×106/l with left shift. Arterial blood gas values in the Emergency Department showed a pH of 7.48, PaCO2 (arterial carbon dioxide pressure) of 43.7 mm Hg and PaO2 (arterial oxygen pressure) of 45 mm Hg, with an SaO2 of 83.5% on a 15 litre face mask. Other serum biochemistry was normal.
Chest radiograph showed homogenous soft tissue opacity in the right upper lung zone, probably a mass lesion compressing the large airways, with right-sided pleural effusion and associated collapse of underlying lung (fig 1).
CT scan chest confirmed a large mass-like lesion occupying the right upper hemithorax with associated collapse of the lung (fig 2 and 3).
Bronchoscopy revealed abnormal rugged, heaped up mucosa involving the right upper lobe with some anthracotic patches bilaterally; bronchoalveolar lavage with endobronchial biopsy was performed.
The bronchoscopic and CT-guided biopsy showed chronic non-specific inflammation without any evidence of granuloma or malignancy.
VATS lung biopsy revealed prominent interstitial and septal fibrosis with Masson-like fibroblastic plugs suggestive of organising pneumonia. No evidence of granuloma or malignancy was seen; changes were consistent with later stages of organised pneumonia (fig 4).
Three-month follow-up chest x rays showed marked improvement with some residual fibrosis in the right upper lobe (fig 5).
Figure 1.
Chest radiograph showed homogenous soft tissue opacity in the right upper lung zone, probably a mass lesion compressing the large airways, with right-sided pleural effusion and associated collapse of underlying lung.
Figure 2.
CT scan chest (axial section) confirmed a mass-like lesion occupying the right upper hemithorax.
Figure 3.
CT scan chest (coronal section) showing a large mass-like lesion causing compression of the large airways and lung atelactasis.
Figure 4.
Video-assisted thoracoscopic lung biopsy revealed prominent interstitial and septal fibrosis with Masson-like fibroblastic plugs suggestive of organising pneumonia. No evidence of granuloma or malignancy was seen; changes were consistent with later stages of organised pneumonia.
Figure 5.
Three-month follow-up chest x rays showed marked improvement with some residual fibrosis in the right upper lobe.
DIFFERENTIAL DIAGNOSIS
The differential diagnosis includes all the conditions presenting as a mass-like lesion, for instance bronchogenic malignancy, lymphoma, lipoid pneumonia, sarcomas, malignant melanoma and inflammatory disorders such as COP.
The investigations should include bronchoscopy with bronchoalveolar lavage and biopsy. The tissue diagnosis should be obtained as early as possible by either CT-guided or VATS biopsy, as appropriate treatment improves survival.
TREATMENT
She was successfully treated with high dose steroids. Methylprednisolone 250 mg every 6 h for 5 days and then shifted to oral prednisone 60 mg/day for 2 weeks.
The oral steroids were changed to 40 mg/day for 4 weeks at follow-up, and gradually tapered over 8 months to 10 mg/day, on which she has been maintained.
OUTCOME AND FOLLOW-UP
She responded to high dose steroids and was extubated in a few days and discharged home in a stable condition.
Her 3-month follow-up showed a marked improvement clinically and radiologically. At the present time, 8 months after her initial presentation, she is maintained on 10 mg oral prednisone and lives an independent life.
DISCUSSION
COP is a distinct clinicopathological syndrome that was first described by Epler et al in 1985.4 It is clinically characterised by flu-like illness followed by cough, dyspnoea and fever. Outcome is good with steroid treatment. A rapidly progressive variant has been identified that responds poorly to standard steroid therapy and has a high mortality.1,5
The roentgenographic manifestations of COP are quite distinctive, with bilateral diffuse alveolar opacities. COP may also present on imaging as a solitary focal lesion usually associated with subacute or chronic inflammatory illness; it usually occurs in the upper lobes and may cavitate. COP is often a pathological diagnosis in this case after surgical excision of a lesion suspected to be a lung cancer on a routine chest radiograph.3
Our patient presented with a lung mass with rapid progression to respiratory failure. This kind of COP presentation is very rare, and, to our knowledge, no similar case has yet been published in the literature. The respiratory failure in this case is probably secondary to large airway compression and lung atelectasis.
The clinical features of dyspnoea, cough and fever associated with leucocytosis in our patient are consistent with the usual presentation of COP. However, the extremely acute presentation and rapid deterioration to respiratory failure is uncommon. The early histological diagnosis is essential in these suspected cases. VATS lung biopsy is currently considered the investigation of choice because a large tissue specimen is necessary for confident diagnosis. The bronchoscopic and CT-guided biopsy failed to provide the definitive answer in our patient. Since areas of fibrosis are patchy and subtle even in severely affected patients, the diagnosis can be missed if lesions are inadequately sampled. VATS biopsy helped us in reaching the correct diagnosis. The histopathological lesions characteristic of COP include excessive proliferation of granulation tissue within the small airways and alveolar ducts, associated with chronic inflammation in the surrounding alveoli.6
Various bacterial and viral infections are associated with COP.6 In our patient, tracheal aspirates, bronchoalveolar lavage fluid and pleural fluid did not grow any organisms. The pleural fluid AFB (acid-fast bacilli) and cytology was negative. The pleural effusion in this case is likely to be secondary to COP, as mentioned in some cases in the literature, and it cleared up completely with steroids.7
The rapidly progressive variant of COP has been reported to respond poorly to steroids.1 In our case report, the patient did respond to steroid therapy with early clinical stabilisation and gradual subsequent radiological resolution of the disease process.
In conclusion, the rapidly progressive variant of COP has a fulminant and rapid course with considerable morbidity and mortality. The differential diagnosis of COP should be considered in focal lung lesion especially when associated with hypoxaemic respiratory failure. Early diagnosis by VATS biopsy aids in quick diagnosis, and institution of high dose steroid treatment results in significant improvement in most patients.
LEARNING POINTS
The differential diagnosis of COP should be considered in focal lung lesion.
A rapidly progressive variant of COP can present as a lung mass.
VATS should be considered early in the diagnosis of COP.
Early histological diagnosis and prompt treatment with high dose steroids result in complete recovery and improved survival.
Acknowledgments
We thank Dr Kanwal Aftab, senior instructor in Pathology, for providing support in reaching the diagnosis and subsequently providing the photographs for this article.
Footnotes
Competing interests: none.
Patient consent: Patient/guardian consent was obtained for publication.
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