Adult Intralobar Pulmonary Sequestration: A Report of Two Cases With Distinct Clinical Presentations

Abstract

Adult pulmonary sequestration (PS) is an uncommon congenital lung anomaly that may present with nonspecific respiratory symptoms and misleading radiological findings.

We report two adult cases of intralobar pulmonary sequestration with distinct clinical presentations. The first case involved a 54-year-old diabetic smoker admitted for recurrent bronchopulmonary infections and severe recurrent hemoptysis requiring blood transfusions. Thoracic computed tomography (CT) angiography revealed a hypervascular lesion in the left lower lobe supplied by aberrant systemic vessels arising from the descending thoracic aorta. Surgical resection was performed and resulted in a favorable outcome. The second case involved a 61-year-old man with a persistent chronic cough resistant to antibiotic therapy. Because the lesion initially raised suspicion of malignancy, CT-guided lung biopsy was performed before the vascular nature of the lesion was recognized, resulting in hemoptysis. Further CT angiography identified an aberrant systemic arterial supply, establishing the diagnosis of intralobar pulmonary sequestration, and the patient subsequently underwent successful surgical resection.

These cases illustrate how pulmonary sequestration in adults may mimic infection or malignancy, highlighting the critical role of CT angiography in diagnosis and pretherapeutic evaluation, particularly to avoid potentially hazardous invasive procedures.

Introduction

Pulmonary sequestration (PS) is a rare congenital pulmonary malformation characterized by nonfunctioning lung tissue that lacks normal communication with the tracheobronchial tree and receives its arterial supply from the systemic circulation rather than the pulmonary artery [1,2]. It accounts for approximately 0.15%-6.4% of congenital pulmonary malformations and is generally classified into two forms: intralobar sequestration (ILS), which shares the visceral pleura with adjacent normal lung, and extralobar sequestration (ELS), which has its own separate pleural covering [1,3]. Venous drainage in intralobar sequestration typically occurs via the pulmonary veins, in contrast to extralobar sequestration, which usually drains via systemic veins; recognizing the arterial supply preoperatively is essential to avoid catastrophic hemorrhage during biopsy or surgical resection. Intralobar sequestration represents approximately 75%-90% of cases and is more frequently diagnosed during adolescence or adulthood, with more than half of cases being diagnosed after the age of 20 [1,4].

Clinical manifestations are often nonspecific and include recurrent pulmonary infections, chronic cough, hemoptysis, chest pain, or incidental radiological findings on imaging performed for unrelated reasons [2,5]. In some instances, the progressive enlargement of the sequestrated tissue over time, related to recurrent respiratory infections, may lead to the development of aneurysmal formations along the aberrant feeding vessel, which can rupture and cause life-threatening hemoptysis [4,6]. Because imaging features can mimic infectious, inflammatory, or neoplastic diseases, diagnosis is often delayed, and invasive procedures may occasionally be performed before the vascular nature of the lesion is identified [3].

Computed tomography (CT) angiography plays a pivotal role in diagnosis by demonstrating both the abnormal pulmonary parenchyma and the aberrant systemic arterial supply, including its origin, caliber, course, and the number of feeding vessels [4,7]. Although CT angiography is typically sufficient for surgical planning, magnetic resonance angiography (MRA) may provide superior vascular characterization in selected cases [8].

By presenting two cases with markedly different clinical presentations, one dominated by severe recurrent hemoptysis and the other by an indolent course mimicking malignancy, this report illustrates the broad clinical spectrum of adult intralobar pulmonary sequestration, including the diagnostic challenges posed by misleading radiological findings and the risk of hemoptysis following CT-guided lung biopsy. These cases emphasize the need for the early recognition of this rare entity and the value of CT angiography in preventing diagnostic and therapeutic pitfalls.

Case presentation

Case 1

A 54-year-old man, a chronic smoker with a 30 pack-year history and a background of type 2 diabetes mellitus, presented with a several-month history of recurrent bronchopulmonary infections associated with chronic productive cough and several episodes of moderate hemoptysis. Two months prior to hospitalization, the patient reported worsening respiratory symptoms with increased cough frequency and recurrent hemoptysis episodes.

During hospitalization, he experienced two further episodes of hemoptysis requiring hemostatic treatment and blood transfusions on two occasions. Physical examination was unremarkable apart from signs of anemia secondary to hemorrhagic episodes, including pallor and tachycardia.

Chest radiography demonstrated a heterogeneous and poorly defined left lower lobar opacity without the obscuration of the left cardiac border (Figure 1).

Figure 1. Chest radiograph: Case 1.

Anteroposterior chest radiograph demonstrating a heterogeneous and poorly defined left lower lobar opacity (arrow) without the obscuration of the left cardiac border

Further investigations were performed to rule out infectious etiologies. Two sputum GeneXpert MTB/RIF tests, one bronchial aspiration GeneXpert assay, and Aspergillus serology were all negative. Laboratory findings are summarized in Table 1.

Table 1. Laboratory investigations for Case 1 with reference ranges.

Values were obtained during the acute hemorrhagic episode requiring transfusion, prior to surgical intervention

Parameter	Result	Reference Range	Units
Hemoglobin (Hb)	7	13-17	g/dL
White Blood Cells (WBC)	14,000	4,000-10,000	/mm³
Platelets (PLT)	350,000	150,000-400,000	/mm³
C-reactive Protein (CRP)	75	<5	mg/L
Serum Creatinine	7	6-12	mg/L
GeneXpert MTB/RIF (×3)	Negative	Negative	-
Aspergillus Serology	Negative	Negative	-

Contrast-enhanced thoracic CT revealed a well-circumscribed, polylobulated, heterogeneous lesion measuring 80 mm in its greatest dimension in the posterior basal segment of the left lower lobe, with multiloculated cystic and bronchiectatic changes. The lesion demonstrated marked hypervascularization, with large tortuous systemic vessels arising directly from the descending thoracic aorta at the junction with the aortic arch (Figures 2-4). These CT findings established the diagnosis of intralobar pulmonary sequestration.

Figure 2. Sagittal contrast-enhanced CT: intralobar pulmonary sequestration (Case 1).

Sagittal reconstruction showing a heterogeneous cystic lesion in the left lower lobe with multiloculated bronchiectatic changes (arrow), consistent with intralobar pulmonary sequestration

CT: computed tomography

Figure 3. CT angiography: aberrant systemic arterial supply (Case 1).

CT angiography demonstrating the aberrant systemic feeding artery (arrow) arising from the descending thoracic aorta and supplying the left lower lobe pulmonary sequestration (Case 1)

CT: computed tomography

Figure 4. Axial contrast-enhanced CT: left lower lobe lesion (Case 1).

Axial CT image showing a heterogeneous left lower lobe lesion (arrow) with cystic and bronchiectatic components associated with surrounding parenchymal distortion

CT: computed tomography

Surgical treatment was indicated given the recurrent hemoptysis and the size of the lesion. The procedure was initially approached by video-assisted thoracoscopic surgery (VATS) but was converted intraoperatively to a left posterolateral thoracotomy due to dense pleural adhesions and challenging vascular anatomy. A left lower lobectomy was performed. Intraoperative findings confirmed a left lower lobe mass consistent with intralobar pulmonary sequestration, characterized by cystic changes and containing viscous mucopurulent secretions. Histopathological examination was performed on the resected specimen; no evidence of malignancy was identified. The detailed pathology report was not available at the time of manuscript preparation.

The immediate postoperative course was complicated by transient respiratory insufficiency requiring intensive care unit (ICU) monitoring for seven days, after which the patient improved progressively and was discharged in stable condition. At one year of follow-up, the patient remained asymptomatic, with the complete resolution of hemoptysis and no radiological evidence of recurrence.

Case 2

A 61-year-old man with no significant past medical history and no history of smoking or other toxic habits presented with a several-month history of chronic cough that persisted despite multiple sequential courses of antibiotic therapy. Physical examination was unremarkable, and the patient showed no signs of respiratory distress or weight loss.

Given the clinical presentation of a pulmonary lesion unresponsive to antibiotics, initial imaging raised a suspicion of malignancy. Because the vascular nature of the lesion had not yet been recognized, a CT-guided percutaneous lung biopsy was performed. Following the procedure, the patient developed hemoptysis. No major hemodynamic instability was observed, and the hemoptysis resolved with conservative management.

Further contrast-enhanced CT and CT angiography demonstrated a heterogeneous mass-like lesion in the posterior basal segment of the left lower lobe (Figure 5), associated with an aberrant systemic feeding artery arising from the descending thoracic aorta (Figures 6, 7). These findings established the diagnosis of intralobar pulmonary sequestration.

Figure 5. Axial contrast-enhanced CT: mass-like lesion (Case 2).

Axial CT scan showing a heterogeneous left lower lobe mass-like lesion (arrow) with cystic and bronchiectatic changes, suggestive of intralobar pulmonary sequestration

CT: computed tomography

Figure 6. CT angiography with 3D reconstruction: aberrant feeding artery (Case 2).

3D CT angiography demonstrating the aberrant systemic feeding artery (arrow) arising from the descending thoracic aorta and supplying the left lower lobe pulmonary sequestration (Case 2). 3D volume rendering was performed on the CT acquisition workstation using the integrated DICOM post-processing software of the CT scanner. No AI-powered tools were used in image generation or processing

CT, computed tomography; DICOM, Digital Imaging and Communications in Medicine

Figure 7. Multiplanar CT angiography: aberrant systemic vessel (Case 2).

Multiplanar CT angiography reconstructions confirming the aberrant systemic feeding artery (arrow) arising from the descending thoracic aorta and supplying the left lower lobe pulmonary sequestration (Case 2). 3D volume rendering was performed on the CT acquisition workstation using the integrated DICOM post-processing software of the CT scanner. No AI-powered tools were used in image generation or processing

CT, computed tomography; DICOM, Digital Imaging and Communications in Medicine

Based on the clinical and radiological findings, the patient was referred for thoracic surgical management and subsequently underwent surgical resection. The postoperative course was uneventful. At follow-up, the patient remained asymptomatic, with the complete resolution of chronic cough and no recurrence of hemoptysis or respiratory infections.

Discussion

Pulmonary sequestration is a rare congenital lung anomaly accounting for approximately 0.15%-6.4% of all congenital pulmonary malformations [5,6]. It consists of nonfunctioning pulmonary tissue that lacks normal communication with the tracheobronchial tree and receives its blood supply from anomalous systemic arteries. It is classified into intralobar and extralobar forms. Intralobar sequestration (ILS) accounts for 75%-90% of cases and most frequently involves the posterior basal segment of the left lower lobe, as observed in both our patients [1,5]. In the large Chinese series by Wei and Li, including 2,625 cases, ILS represented the vast majority of pulmonary sequestrations, and more than half of all cases were diagnosed after the age of 20 [5].

The clinical presentation of adult pulmonary sequestration is often nonspecific, leading to delayed diagnosis. Recurrent pulmonary infections, chronic cough, sputum production, chest pain, and hemoptysis are the most commonly reported symptoms [1,9,10]. In the retrospective series by Ren et al., cough and expectoration were the most frequent symptoms, while hemoptysis occurred in approximately one-third of patients [1]. Gompelmann et al. similarly reported that adult patients often present with recurrent respiratory infections and that the diagnosis is frequently delayed because of the nonspecific clinical picture [10]. Some patients remain asymptomatic and are diagnosed incidentally on imaging performed for unrelated reasons [2].

The clinical presentation differed markedly between our two patients. The first case presented with recurrent bronchopulmonary infections and severe recurrent hemoptysis requiring transfusion, whereas the second presented with isolated persistent chronic cough resistant to antibiotic therapy, initially raising suspicion of a neoplastic or infectious etiology.

Hemoptysis is a major and potentially life-threatening manifestation of intralobar sequestration in adults, as the lesion is supplied by high-pressure systemic arteries. With increasing age and successive respiratory infections, the sequestration may progressively enlarge and develop aneurysmal formations along the aberrant vessel, which can rupture and cause massive hemoptysis [3,6]. Although mild hemoptysis is relatively common, massive hemoptysis remains a rare but serious complication [3,10]. In our first case, recurrent major hemoptysis requiring transfusion was the key clinical feature prompting definitive investigation and surgical management. As reported by Hertzenberg et al. in their series of adult ILS cases, hemoptysis may be the presenting symptom that leads to diagnosis [11]. This observation underlines that pulmonary sequestration should be systematically considered in the differential diagnosis of recurrent or unexplained hemoptysis, particularly when associated with lower lobe abnormalities on imaging.

Imaging is central to the diagnosis of pulmonary sequestration. Chest radiography is frequently nonspecific and may reveal a mass, consolidation, cystic lesion, or recurrent localized infiltrate [2,8]. Multidetector CT angiography is considered the imaging modality of choice because it allows the accurate visualization of both the abnormal lung parenchyma and the aberrant systemic arterial supply, including its origin, caliber, course, and the number of feeding vessels [4,8]. As emphasized by Felker and Tonkin in their imaging review, the identification of the anomalous systemic artery is the cornerstone of diagnosis [7]. Remy further highlighted that contrast-enhanced thoracic CT not only identifies the aberrant artery but also provides detailed information on the sequestrated tissue and that the aberrant arterial supply can be visualized in approximately 70%-80% of cases [8]. Chabi and Revel reported a representative case of left posterobasal thoracic mass where CT angiography was essential for establishing the correct diagnosis and avoiding unnecessary invasive procedures [12].

In our first patient, contrast-enhanced CT demonstrated a hypervascular left lower lobe lesion supplied by large tortuous systemic vessels arising directly from the descending thoracic aorta, establishing the diagnosis preoperatively. In the second case, the diagnosis only became evident after advanced vascular imaging identified the aberrant arterial supply, highlighting the critical importance of systematic vascular evaluation before any invasive procedure.

Our second case illustrates the risk of misdiagnosis when the vascular nature of the lesion is not recognized prior to intervention. Because imaging findings may mimic chronic pulmonary infection, localized bronchiectasis, fungal disease, or primary lung malignancy, invasive diagnostic procedures may be performed before the correct diagnosis is established [3,9]. These entities represent the principal differential diagnoses in adults presenting with persistent lower lobe pulmonary lesions.

In our patient, CT-guided lung biopsy was complicated by hemoptysis, emphasizing the potential hemorrhagic risk associated with unrecognized high-pressure systemic arterial vascularization. Hauer et al. similarly reported diagnostic and therapeutic difficulties related to the delayed recognition of the vascular anatomy in their series [9]. Careful vascular evaluation before any invasive pulmonary procedure is therefore essential to prevent potentially life-threatening complications.

Surgical resection is the standard treatment for symptomatic pulmonary sequestration and is generally recommended even in asymptomatic patients because of the risks of recurrent infection, hemorrhage, and progressive parenchymal destruction [13-15]. Traibi et al., in their series of adult ILS treated surgically, reported a progressive shift toward minimally invasive approaches with favorable outcomes [12]. Video-assisted thoracoscopic surgery (VATS) is increasingly used and is associated with reduced postoperative pain, shorter drainage duration, and shorter hospital stay compared with open thoracotomy [1,13]. However, conversion to open thoracotomy may be required in complex cases with dense pleural adhesions or challenging vascular anatomy, as occurred in our first patient. Endovascular embolization may represent an alternative option for selected high-risk surgical candidates, although long-term outcomes with this approach remain less well-established [14].

A limitation of this report is the absence of a complete histopathological description for Case 1, as the detailed pathology report was not available at the time of manuscript preparation, although histopathological examination confirmed the diagnosis and excluded malignancy.

Conclusions

Pulmonary sequestration in adults remains a diagnostic challenge because of its variable and often nonspecific clinical and radiological presentation. In adults presenting with recurrent lower lobe infections, chronic respiratory symptoms, hemoptysis, or atypical pulmonary masses unresponsive to conventional therapy, this diagnosis should be actively considered, particularly when imaging findings are unusual or misleading. Our cases demonstrate that CT angiography is indispensable for identifying aberrant systemic vascularization, confirming the diagnosis, and guiding safe therapeutic management. Vascular evaluation should precede any invasive procedure to avoid potentially life-threatening hemorrhagic complications, as illustrated by Case 2. Surgical resection remains the treatment of choice for symptomatic patients and yields favorable long-term outcomes.