Acta Chir Belg, 2008, 108, 468-470
Unusual Manifestation of Bronchiolitis Obliterans Organizing Pneumonia D. Kilic*, A. Findikcioglu*, E. Kocer**, A. Hatipoglu* Baskent University Faculty of Medicine, Departments of *Thoracic Surgery and **Pathology Ankara , Turkey.
Key words. Bronchiolitis obliterans ; pulmonary nodula ; bronchial carcinoma ; echinococcosis ; complicated hydatid cyst. Abstract. Bronchiolitis obliterans organizing pneumonia (BOOP) is an uncommon fibrotic lung disease characterized by involvement of the small conducting airways. BOOP has a wide spectrum of radiologic and clinical features. Usually, it appears radiologically as multiple alveolar patchy areas of consolidation. However, different presentations have also been described. We report two cases of solitary masses of the lung that preoperatively presented as malignant lesions but were subsequently diagnosed as bronchiolitis obliterans organizing pneumonia. One of the cases of BOOP was probably secondary to suppuration of a hydatid cyst. Complicated hydatid cyst may give rise to various clinical manifestations and may present radiologically as a solid lung mass. The radiologic findings of pulmonary ruptured or complicated hydatid cyst may resemble primary lung tumor. Open surgery can be required for not only for diagnosis but also for treatment of solitary BOOP. A review of the literature is also presented.
Introduction Bronchiolitis obliterans with organizing pneumonia (BOOP) is a pathological syndrome common to a variety of pulmonary inflammatory disorders. It is defined as the occurrence of buds of granulation tissue consisting of fibroblasts and collagen within the lumen of the distal air spaces (1). The clinical course and features of bronchiolitis obliterans may vary considerably according to the etiology, histologic pattern, and disease stage (2). Also radiological apperances of the BOOP may vary. Characteristic imaging findings include patchy multifocal areas of alveolar infiltration and ground-glass opacities, which are often bilateral, subpleural, or bronchocentric in distribution (3). However, other presentations have also been described. A single area of consolidated solitary pulmonary nodule is a less common appearance (4). Hydatid cysts of the thorax, when complicated by suppuration may mimic several pulmonary lesions including carcinomas of the lung. Treatment of pulmonary hydatid cyst is surgical. However, if surgical treatment is delayed owing to earlier medical treatment of an uncomplicated hydatid cyst, the cyst may rupture and suppurate. This suppuration in turn may lead to BOOP. Clinical manifestations and imaging findings are usually subtle and diagnosis is sometimes impossible on clinical grounds. Definitive diagnosis of the disease must be resolved by tissue diagnosis, preferably by open lung biopsy. We present two patients with BOOP mimicking bronchial carcinoma. Both patients underwent thoracic
surgical intervention for confirmation of the diagnosis and subsequent treatment. Case Report Case 1 A 55-year-old male smoker was referred to our clinic because of a mass in the right lung. His primary complaint was cough of 3 weeks’ duration. Laboratory tests were normal. Computed tomography (CT) of the chest revealed a 4 3 cm pulmonary mass with irregular borders and heterogeneous density resembling bronchogenic carcinoma (Fig. 1). No endobronchial pathology was found on bronchoscopy. Transthoracic needle aspiration biopsy was not preferred because the mass got larger in a short time. The patient underwent right thoracotomy, and wedge resection of the superior lobe. Histopathologic examination revealed intra-bronchiolar and intra-alveolar granulation tissue consistent with BOOP. The patient’s postoperative course was uneventful, and he was discharged on the seventh day after the operation. At 17 months follow-up, the patient was well, and a chest roentgenogram showed no evidence of recurrence. Case 2 A 59-year-old female nonsmoker was referred to our clinic because of a mass in the right upper lobe of the lung. Her complaints were cough and fever of 2 months’
Unusual Manifestation of BOOP
Fig. 1 CT scan of the chest showing a cavitary lesion of the right lung “bronchiolitis obliterans” simulating bronchial carcinoma.
duration. CT scan of the chest showed a 4 4 cm pulmonary mass in the right upper lobe. Bronchoscopy and lavage revealed no significant abnormalities. Transthoracic needle aspiration biopsy was performed but histopathological examination was not diagnostic and open biopsy was performed by a right posterolateral thoracotomy. A 4 5 cm complicated cyst was observed in the superior lobe, a cystotomy and wedge resection was performed. Histologic examination revealed BOOP associated with a hydatid cyst. There were bronchiolar plugs of granulation tissue, and the surrounding interstitial and air spaces had been infiltrated by mononuclear cells with foamy macrophages, also, cuticules were observed in cystotomy material. The patient was discharged on the sixth day after the operation without any complications. At 23 months follow-up, the patient’s postoperative course was uneventful. Discussion Bronchiolitis obliterans, first described by Raynoud in 1835, is a fibrotic lung disease involving the small conducting airways. In a review of 50 cases, Epler and coworkers (5) first described BOOP as a clinicopathological entity. Incomplete resolution of inflammation between the alveoli to the respiratory bronchioles causes organizing pneumonia. BOOP is always idiopathic and presents as a clinico-radiologic syndrome of subacute pneumonia that improves with corticosteroids. It may occur secondary to lung injury, resulting especially from infection or drug toxicity, or it may develop in the
469 context of connective tissue diseases or after lung or bone marrow transplantation (1). BOOP may occur secondary to lung infections. However we found only a few reports on BOOP associated with hydatid cyst or secondary complicated hydatid cyst in the English literature (6, 7). Our patient had BOOP, which was either associated with, or secondary to, a suppurative hydatic cyst of the lung presenting as pulmonary mass. The cyst in the current case had rested within the parenchyma for a long time to form secondary changes and atelectasis ; it resembled pneumonia, carcinoma of the lung or non-specific pulmonary infection. Bacterial infection, which is the most serious complication of perforation, increases attenuation coefficients of the hydatid cyst. Because of the solid density of an infected hydatid cyst, differentiation from an abscess or neoplasm may be very difficult. Bronchiolitis obliterans organizing pneumonia is usually associated with benign conditions such as inflammatory diseases, and it may rarely mimic malignant neoplasm of the lung (8). Bronchoscopy should only be performed when the mass is suspected to be malignant. Bronchoscopy was performed in both of our patients but did not provide a clue for diagnosis. The most common imaging findings of BOOP are multiple alveolar patchy and often migratory pulmonary opacities. Other imaging presentations consist of diffuse infiltrative opacities as interstitial lung disease or focal pneumonia (4). The most common pattern is consolidation on CT scan. Lee and coworkers found consolidation on 79% of CT scans, most of which were bilateral, nonsegmental, and patchy in distribution. Nodules were present in 30% of patients. However, solitary pulmonary nodules were not seen (3). In 2 other series of 31 and 58 patients, no solitary nodules were found (9, 10). Radiologic appearances of the masses in our patients were unusual. In each case, the chest radiograph and CT appearance was that of a mass with irregular borders. One of our patients also had a cavitation in the center of the mass that was highly suggestive of bronchial carcinoma. The method of establishing the diagnosis is histopathological examination, especially for a solitary nodule. Video-assisted thoracoscopy, and transthoracic or transbronchial biopsies can be performed (8). However, the diagnosis of BOOP must be considered with caution because it may be seen adjacent to a bronchial carcinoma (4). Excisional biopsy via thoracotomy was prefered for both our patients because the solitary nodules simulated bronchial carcinoma. During the operation, frozen section examination revealed a nonmalignant lesion, and no further treatment was required. In conclusion, BOOP may develop secondary to a complicated thoracic hydatic cyst. Radiologic examination may not provide the correct diagnosis and might be suspicious for a malignant mass. Transthoracic CT-
470 guided biopsy may fail to give a specific diagnosis. These nodular cysts are rare and look like almost every other tumor, including malignant neoplasm. Surgical excision achieves curative therapy and definitive diagnosis of BOOP for these lesions.
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A. Findikcioglu Alper Findikcioglu Department of Thoracic Surgery Baskent University Faculty of Medicine Adana Teaching and Medical Research Center Dadaloglu Mah. 39. Sokak No : 6, Yüregir 01250 Adana, Turkey Tel. : +90-322-3272727 Fax : +90-322-3271274 E-mail :
[email protected]
