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Abstract
Bronchopulmonary sequestration is a rare condition characterised by the presence of nonfunctional, dysplastic lung tissue. This tissue receives blood supply from the systemic circulation. In this case report, we document an exceptional presentation of a woman in her 50s where bronchopulmonary sequestration in the right upper lung lobe led to haemoptysis. This sequestration received blood supply from a pulmonary artery branch, which is unusual and contrary to the usual systemic circulation. The patient underwent a right upper lobectomy, which confirmed the diagnosis of pulmonary sequestration on histopathology. The unique vascular supply and location of this case challenge conventional diagnostic and management approaches. It emphasises the necessity for meticulous evaluation and consideration of alternative vascular sources in bronchopulmonary sequestration cases.
- Respiratory medicine
- Pathology
- Anatomic Variation
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Background
Bronchopulmonary sequestration is a rare congenital foregut malformation of lung tissue that is devoid of respiratory function and obtains its blood supply from systemic circulation. This dysplastic tissue remains isolated from the tracheobronchial tree, lacking any direct communication.1
The presentation of bronchopulmonary sequestration might vary from being an incidental finding on chest imaging to recurrent pneumonia and/or haemoptysis. The incidence of bronchopulmonary sequestration is very rare in adults, accounting for fewer than 3 cases per 10 000 adults according to one study.2 Here we report an extremely unusual case of right upper lobe bronchopulmonary sequestration receiving blood supply from a segmental branch of the right pulmonary artery and presenting as haemoptysis in a female in her 50s.
Case presentation
A female in her 50s with a history of hypertension and obesity (BMI 43.8 kg/m²), presented to the Emergency Department with a one and a half year history of haemoptysis, shortness of breath and an undocumented low-grade fever for the past 4 days. Over the last week, the frequency of blood in the sputum had significantly increased, with multiple episodes of haemoptysis every 1 to 2 hours. There was no associated chest pain or weight loss. She denied smoking, alcohol or illicit drug use, and her vital signs were within normal limits. Respiratory examination including the rest of the clinical examination was normal. Past medical and surgical history was significant for cholecystectomy 2 years ago and hysterectomy 10 years ago.
When the patient initially presented 1.5 years ago, she experienced similar episodes of blood in sputum which was not associated with cough, fever or dyspnoea. She had undergone a bronchoscopy-guided biopsy for a right lung endobronchial growth, which yielded inconclusive results. Bronchioalveolar lavage was negative for Mycobacterium tuberculosis, and no pathogens were isolated in the culture. She was managed conservatively at that time.
Investigations
Laboratory investigations revealed normal complete blood counts, with haemoglobin of 14.2 g/dL, leucocyte count of 7.0×109 /L with 51.2% neutrophils, 27.6% lymphocytes and 9.3% monocytes and platelet count 209×109 /L. Serum IgE levels were elevated (354 IU/mL). Arterial blood gas analysis showed a low pO2 of 39.7 mmHg, pCO2 of 43.6 mmHg and O2 saturation of 77.70%. On her previous visit 1.5 years ago, the chest X-ray revealed an opacity in the right upper lung zone (figure 1). During her current visit, the chest X-ray displayed no significant changes. CT imaging revealed a soft tissue density, non-enhancing structure in the right upper lung lobe measuring 27×36×33 mm, supplied by a large segmental branch of the right pulmonary artery, with prominent mediastinal lymph nodes noted (figure 2). Bronchoscopy-guided biopsy was attempted but failed due to patient intolerance, leading to a recommendation for lobectomy by cardiothoracic surgery.
Chest X-ray of the patient when she initially presented one and a half years ago, shows an opacity with irregular borders in the right upper lung zone.
A, B CT scan showing aberrant formation of segmental lung tissue within the right upper lobe supplied by a large segmental branch of the right pulmonary artery.
Differential diagnosis
Diagnostic procedures were employed to investigate the potential conditions after bronchoalveolar lavage (BAL), and tests for tuberculosis (TB) ruled out infectious causes. The differential diagnosis for this case included arteriovenous fistula (AVF), malignancy and pulmonary sequestration. AVF was considered due to its potential to cause haemoptysis through abnormal blood flow and rupture. Malignancy was a concern because of the patient’s history of an inconclusive endobronchial growth and persistent symptoms. Pulmonary sequestration, characterised by abnormal lung tissue with its own blood supply, was also a possibility given the chronic haemoptysis.
Treatment
Cardiothoracic surgery involving a right upper lobectomy was performed through a right posterolateral thoracotomy. During the procedure, a large mass involving the right upper bronchus and pulmonary artery was identified. After deflating the lung, the right superior pulmonary vein was isolated and ligated. The truncus arteriosus was then identified, ligated and divided. Subsequently, the posterior segmental artery was clipped and ligated. The right upper lobe bronchus was then resected. An intrapleural drain was placed. Following these steps, the thoracotomy incision was closed, and the wound was closed in layers. Samples of lymph nodes from levels 2, 7 and N1 hilar lymph nodes were sent for biopsy to further evaluate the extent and nature of the mass. Histopathological analysis of the biopsy revealed features consistent with pulmonary sequestration with associated bronchiectasis figure 3. The lymph node analysis demonstrated benign reactive lymph nodes in levels 2 and 7, while the N1 hilar lymph nodes exhibited fibro adipose tissue with crushed lymphoid aggregates and thick-walled blood vessels.
(H&E 2x x): Lung parenchyma demonstrates collapsed air spaces along with intraparenchymal hemorrhagehaemorrhage, edemaoedema, hemosiderin laden macrophages, foci of lymphocytic infiltrates, anthracotic pigment deposition, fibrosis/sclerosis and aggregates of neutrophils forming microabscesses. This area is surrounded by large thick-walled blood vessels (*). These images show all histological features of intralobar pulmonary sequestration.
Outcome and follow-up
Postoperative chest X-ray showed an expansion of the right upper lung zone (figure 4). The patient was discharged home uneventfully on postoperative day 6 and reported no complications on follow-up.
Postoperative chest X-ray showing an expansion of the right upper lung zone.
Discussion
Bronchopulmonary sequestration is a rare anomaly that poses a diagnostic challenge for clinicians due to its complex and variable presentations. It accounts for only 0.15 to 6.4% of all cases of congenital lung malformations and is often misdiagnosed, with one study reporting an average incorrect preoperative diagnosis rate of 58.6%.3 4 Diagnosis is most often confirmed postoperatively through histopathology.
Intralobar and extralobar are the two main types of bronchopulmonary sequestration. Intralobar sequestration, which is more common, is found within the lungs and lacks its own visceral pleura. Extralobar sequestration is located outside the lung and has its own visceral pleura. Intralobar sequestration typically occurs in paediatric and adolescent populations and is rarely seen in adults. In our case, the patient had an intralobar sequestration, which is typically diagnosed at age 20 or younger in 60% of cases and rarely occurs in adults older than 40 years.3
A study found that 97.8% of 400 cases affected the lower lobes, with only eight cases of upper lobe pathology reported.5 This underscores the rarity of our patient’s presentation with right upper lobe pathology, leading to differentials including arteriovenous fistula malformation, malignancy and pulmonary sequestration.
In intralobar sequestration, the systemic arterial supply is usually via the descending thoracic aorta (72%) or less commonly from the abdominal aorta, coeliac axis or splenic artery (21%); the intercostal artery (3.7%); and rarely from the subclavian, internal thoracic and pericardiophrenic arteries.5 Remarkably, only two reported cases have documented bronchopulmonary sequestration receiving its blood supply from the pulmonary artery instead of the systemic circulation. One case involved a 64-year-old man with a combined anomaly of the bronchus and pulmonary artery, detected incidentally on routine chest radiography.6 Another case involved an 18-year-old female with extralobar sequestration located between the upper and lower right lung lobes supplied by a pulmonary artery feeding vessel.7 Our case represents the third instance of this rare phenomenon, highlighting the importance of understanding such variations in arterial supply for accurate diagnosis and appropriate management of bronchopulmonary sequestration. This variability in blood supply may suggest that the definition of bronchopulmonary sequestration as receiving blood supply from the systemic circulation may need reconsideration.
The clinical manifestations of pulmonary sequestration are varied and include cough, sputum, fever, haemoptysis and chest pain.4 In a recent single-centre retrospective study, it was observed that 22.7% of patients were incidentally discovered through chest CT scans during health examinations, without exhibiting any specific symptoms.1
CT with contrast and CT angiography are the preferred imaging modalities for pulmonary sequestration, as they demonstrate anomalous arterial supplies. This imaging is also helpful in planning surgical management. The presentation on CT may vary, with the lesion commonly appearing as a homogeneous or inhomogeneous solid mass, with or without definable cystic changes. According to one study, the most common CT findings were mass lesions, cystic lesions, cavitary lesions, pneumonic lesions, bronchiectasis and intrapulmonary cord-like shadows.1 Digital subtraction angiography, which was previously the gold standard, has become obsolete due to its invasiveness and radiation exposure.8
There have been no established guidelines for the treatment of bronchopulmonary sequestration, but the generally accepted mode of treatment involves surgical resection, even in asymptomatic individuals, to prevent infections and lung tissue damage.9 Lobectomies and segmental lung resections are commonly performed surgical procedures. Video-assisted thoracoscopic resections are also successfully used in simple sequestrations without cavitation or hilum adhesion.10 In this case, although video-assisted thoracoscopic surgery or robotic-assisted thoracic surgery would ideally have been the initial approach due to its less-invasive nature and the unclear diagnosis, the decision to proceed with open thoracotomy was made because of the ambiguity of the imaging findings and the necessity to exclude malignancy. This approach allowed for a comprehensive evaluation, including mediastinal and regional lymph node biopsy, which was critical due to the patient’s significant haemoptysis and the need for urgent intervention.
LEARNING POINTS
Bronchopulmonary sequestration can manifest atypically in adults, challenging conventional diagnostic expectations.
The clinical presentation of an adult who is otherwise healthy with recurrent haemoptysis, pneumonia or chest pain should prompt a differential diagnosis of bronchopulmonary sequestration.
Recognition of the possibility of bronchopulmonary sequestration receiving blood supply from a pulmonary artery branch, rather than systemic circulation, is crucial. This underscores the importance of considering alternative vascular supplies in suspected cases for accurate diagnosis and appropriate management.
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Footnotes
Contributors The following authors were responsible for drafting the text, sourcing and editing clinical images, investigating results, drawing original diagrams and algorithms and critically revising important intellectual content: KH, SS, SHF and JAK. ChatGPT-4 was used to assist in correcting grammatical and English language errors in the text.The following authors gave final approval of the manuscript: KH, SS, SHF and JAK. KH is responsible for the overall content as guarantor. ChatGPT was used to assist in correcting grammatical and English language errors in the writing of this case report. The content and scientific accuracy of the report were carefully reviewed and approved by the authors.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.