19-21 CASE REPORT 19 SA JOURNAL OF RADIOLOGY • July 2005 Introduction Bronchiolitis obliterans organising pneumonia (BOOP) is a distinct enti- ty with various clinical, radiographic and prognostic features. Patholo- gically it is characterised by the pres- ence of granulation tissue polyps within the lumina of bronchioles and alveolar ducts with patchy areas of organising pneumonia. Chronic inflammation is noted in the walls of the surrounding alveoli with pre- served lung architecture. The pre- ferred term is cryptogenic organising pneumonia (COP) when no aetiology is found.1-3 We report on a patient recently seen with this condition. Case report A 36-year-old woman presented with a history of persistent non-pro- ductive cough for 4 weeks. She com- plained of pleuritic chest pain, night sweats and progressive shortness of breath with decreased effort tolerance, and she remained symptomatic despite numerous antibiotics. There were no contributing factors in the history to elucidate the aetiology of her symptoms. There was no history of previous allergies, drug use, recent upper respiratory tract infection, sig- nificant dust exposure, radiation ther- apy, transplantation or autoimmune disease. Systematic examination revealed a young female in respiratory distress, with decreased breath sounds and fine inspiratory crackles at both bases. The cardiovascular system and the rest of the examination were normal. The blood results revealed mild microcytic hypochromic anaemia. The C-reactive protein and erythro- cyte sedimentation rate (ESR) were within normal limits. The urea and electrolytes were normal. Liver func- tion tests demonstrated a mildly ele- vated alanine transaminase (66 IU/l), aspartate transaminase (79 IU/l) and lactate dehydrogenase (284 IU/l). The rheumatoid factor and anti- nuclear factor were negative. Serological tests for Legionnaire’s dis- ease, mycoplasma and chlamydia were negative. Sputum examination revealed no organisms on gram-stain and culture. Thoracentesis demon- strated a transudate. The lung function test showed a moderate restrictive pattern. The chest X-ray demonstrated bilateral basal infiltrates with blunting of both costophrenic angles suggest- ing pleural effusions (Fig. 1). Despite intravenous antibiotics there was no clinical response. High- resolution computerised tomography (HRCT) scan of the chest was then performed which demonstrated patchy bilateral air space consolida- tion involving predominately the lower lobes. This consolidation appeared to be subpleural and peri- bronchovascular in distribution. Small bilateral pleural effusions were also confirmed (Fig. 2). There was evi- dence of patchy ground-glass opacifi- cation in the lower lobes. The diagno- sis of atypical pneumonia and BOOP was considered. Bronchiolitis oblit- erans organising pneumonia (BOOP) or cryptogenic organising pneumo- nia (COP) V K Bhagwandas MB BCh, FCRad (D) (SA) X-ray Department Lenmed Clinic Lenasia Johannesburg R Morar MB ChB, MMed, FCP (SA), FCCP Department of Pulmonology University of the Witwatersrand Johannesburg Hospital H D Bhula BSc (Micro), MB BS (Bombay), FCP (SA) Lenmed Clinic Lenasia Johannesburg Fig. 1. Bibasal infiltrate with blunting of the costophrenic angles suggesting effusions. 19-21 7/29/05 3:19 PM Page 19 CASE REPORT 20 SA JOURNAL OF RADIOLOGY • July 2005 An open lung biopsy of the lingu- la and left lower lobe segments revealed interstitial thickening with lymphocytes and plasma cells, with granulation tissue-type exudates and fibroblast proliferation filling the alve- olar spaces (Fig. 3). There was no evi- dence of tuberculosis, sarcoidosis or malignancy. Multiple sections exam- ined revealed features in keeping with BOOP. Following confirmation of the diagnosis of idiopathic BOOP, treat- ment with corticosteroids was com- menced at a dose of 0.5 mg /kg. A fol- low-up chest X-ray obtained 3 weeks post treatment (Fig. 4) showed signif- icant resolution of the bilateral basal infiltrates. Discussion BOOP or COP is an inflammato- ry lung disease and thus is related to the inflammatory pathway rather than the fibrosing pathway that occurs with usual interstitial pneumonitis / idiopathic pulmonary fibrosis (UIP/ IPF).2 BOOP may be classified as fol- lows1-3: (i) idiopathic; (ii) rapidly pro- gressive; (iii) focal nodular; (iv) multi- ple nodular; (v) post infection; (vi) drug related; (vii) autoimmune dis- ease; (viii) bone marrow transplanta- tion; (ix) lung transplantation; (x) renal transplantation (xi) radiothera- py; (xii) environment-related; (xiii) miscellaneous. Idiopathic BOOP The clinical presentation of idio- pathic BOOP, which is the most com- mon type encountered, and the type present in our patient, is one of flu- like illness with fever, mild cough and dyspnoea. Haemoptysis is uncom- mon. Bilateral basal crackles are noted. Pulmonary function tests demonstrate a restrictive pattern and abnormal diffusing capacity. The ESR is usually raised.1-3 Chest X-ray findings may include unilateral or bilateral patchy alveolar airspace consolidation which is sub- pleural and peribronchial in location, usually in the lower regions of each lung. The consolidation may be mul- tifocal and non-segmental or unilater- al and focal. Nodules 3 - 5 mm in size and other linear opacities may also be seen. Pleural thickening and/or effu- sions may also be noted.1, 3 HRCT scans may show bilateral areas of consolidation and ground- glass opacities are seen mainly in a peripheral location.4 Two types of linear opacities may be noted. The first extends in a radial manner along the line of the bronchi toward the pleura, and the second occurs in the subpleural location with no relation to bronchi. Both types usually occur in the lower lobes, frequently associ- ated with multifocal areas of consoli- dation.5 Centrilobular nodules mea- suring 3 - 5 mm in diameter may be observed. Bronchial wall thickening and cylindrical bronchial dilation may also be noted. Small ill-defined nodu- lar opacities of 1 - 10 mm in diameter may also be seen. Pleural effusions may be present.4,5 Cavitating lung masses are rare.6 The differential diag- nosis includes eosinophilic pneumo- nia, pulmonary haemorrhage, multi- Fig. 2. Patchy bibasal consolidation with subpleural and peribronchovascular distribution. Fig. 3. Interstitial thickening with lymphocytes and plasma cells with granulation tissue type exudates and fibroblast proliferation filling the alveolar spaces. Fig. 4. Significant resolution of bibasal infil- trates post treatment. 19-21 7/29/05 3:19 PM Page 20 CASE REPORT 21 SA JOURNAL OF RADIOLOGY • July 2005 focal infection and diffuse alveolar damage.4-8 Magnetic resonance imaging (MRI) currently has no significant diagnostic role in BOOP, but may have a role to play in the follow-up of patients with BOOP. It may be used to assess the response to treatment and disease activity. Broncho-alveolar car- cinoma may mimic BOOP. The white lung sign is an uncommon finding in pulmonary consolidation evaluated with heavily T2-weighted sequences. This sign is usually negative in patients with BOOP but positive in patients with broncho-alveolar carci- noma.9 Therefore MRI has a potential role to play in the exclusion of other conditions. Ultrasound may assist in the char- acterisation of pleural effusions and for the guidance of pleurocentesis. The gold standard for confirming the diagnosis is a lung biopsy either by video-assisted thoracoscopic surgery (VATS) or open lung biopsy. Histologically there is evidence of intraluminal organising and polypoid granulation tissue within small bron- chioles, alveolar ducts and alveoli. There are also foamy macrophages, inflamed alveolar walls and evenly spaced rounded balls of myxomatous connective tissue present.1-3 The diagnosis of BOOP/COP is definite in a patient with a typical pathologic presentation on a lung biopsy of sufficient size. However, transbronchial lung biopsy (smaller samples) in a patient with typical clin- ico-radiological presentation may suggest the diagnosis of BOOP. Conditions that mimic BOOP include pulmonary lymphoma, chronic eosinophilic pneumonia, broncho-alveolar carcinoma and pul- monary embolism. It is important that the classified aetiological factors related to BOOP be excluded from the history, exami- nation and investigations, especially infection, drug or radiation-induced pulmonary reaction, autoimmune diseases and systemic inflammatory disease. When no aetiology is found, as in our patient, the organising pneu- monia may be called cryptogenic. This condition is a form of idiopathic interstitial pneumonitis. Finally, treatment for this condi- tion is usually prolonged corticos- teroid administration for approxi- mately 6 - 12 months in tapering doses depending on clinical response. The prognosis is usually good, except in a rapidly progressive form of this condition.1, 3 References 1. Cordier JF. Cryptogenic organizing pneumo- nia. Clin Chest Med 2004; 25: 727-738, vi-vii. 2. American Thoracic Society; European Respiratory Society. American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. This joint statement of the American Thoracic Society (ATS), and the European Respiratory Society (ERS) was adopt- ed by the ATS board of directors, June 2001 and by the ERS Executive Committee, June 2001. Am J Respir Crit Care Med 2002; 165: 277-304. 3. Epler GR. Bronchiolitis obliterans organising pneumonia. Arch Intern Med 2001; 161: 158- 164. 4. Webb WR, Muller NL, Naidich DP. High- Resolution CT of the Lung. 3rd ed. Philadelphia: Lippincott-Raven, 2001: 373-378, 529-537. 5. Murphy JM, Schnyder P, Verschakelen J, Leuenberger P, Flower CD. Linear opacities on HRCT in bronchiolitis obliterans organising pneumonia. Eur Radiol 1999; 9: 1813-1817. 6. Akira M, Yamamoto S, Sakatari M. Bronchiolitis obliterans organising pneumonia manifesting as multiple large nodules or mass- es. Am J Roentgenol 1998; 170: 291-295. 7. Muller N, Staples C, Miller R. Bronchiolitis obliterans organizing pneumonia: CT features in 14 patients. Am J Roentgenol 1990; 154: 983- 987. 8. Nishimura K, Itoh H: High-resolution comput- ed tomographic features of bronchiolitis oblit- erans organizing pneumonia. Chest 1992; 102: 26S-31S. 9. Murphy J, Schnyder P, Herold C, Flower C. Bronchiolitis obliterans organising pneumonia simulating bronchial carcinoma. Eur Radiol 1998; 8: 1165-1169. 19-21 7/29/05 3:19 PM Page 21