Pulmonary sequestration is a congenital syndrome characterized by abnormal systemic blood supply to the lung, usually the lower lobe. The anomaly causes a predisposition for pulmonary complications such as infection and hemoptysis. There are two types of sequestrations: intralobar and extralobar. As the name implies, the intralobar sequestration is located within the normal lung (Fig. 97-1), whereas the extralobar sequestration is separate from the normal lung, enclosed in its own pleural envelope (Fig. 97-2). One should be aware of other associated anomalies such as abnormal communication of the bronchial tree, systemic venous drainage, rare communication to the foregut, and diaphragmatic hernia (Table 97-1). In addition, the aberrant systemic vessel can arise from any systemic intrathoracic or upper abdominal vessel, including the aorta, the subclavian artery, and even the coronary arteries. Although they are most commonly found in the left lower lobe, sequestrations also occur in the right lower lobe and the left or right upper lobe.
Intralobar pulmonary sequestration.
Extralobar pulmonary sequestration.
Table 97-1DISTINGUISHING CHARACTERISTICS OF ELS VERSUS ILS |Favorite Table|Download (.pdf) Table 97-1 DISTINGUISHING CHARACTERISTICS OF ELS VERSUS ILS
|CHARACTERISTICS ||ELS ||ILS |
|Incidence ||Rare ||Uncommon |
|Sex predominance ||4:1 M:F ||1.5:1 M:F |
|Laterality ||Left > right ||Left > right |
|Pleural involvement ||Yes ||No |
|Arterial supply ||Systemic; rare pulmonary ||Systemic |
|Venous drainage ||Systemic ||Pulmonary |
|Associated anomalies ||>50% ||Rare |
|Diaphragmatic hernia ||30% ||Isolated |
|Clinical aspects |
Age at recognition
Triangular mass lesion
Adolescent, young adult
Lower lobe abscess
Extralobar pulmonary sequestrations tend to present at an early age with respiratory distress because they are associated with other congenital anomalies such as diaphragmatic hernias. They have systemic venous drainage and no bronchial communication. In contrast, intralobar sequestrations are commonly diagnosed in adulthood, present with frequent pulmonary infections or hemoptysis, have pulmonary venous drainage, have normal bronchial communication, and are rarely associated with other anomalies.1–3 Fever, cough, multiple pulmonary infections, and hemoptysis can occur, although up to 13% can be asymptomatic.4 The affected lobe tends to develop chronic changes owing to recurrent infections with eventual cystic destruction of the parenchyma. A chest x-ray that reveals consolidation along the medial aspect of the lower lobe should arouse suspicion of a sequestration. A chest CT scan or computed tomographic angiography (CTA) can confirm the diagnosis of the sequestration, so conventional angiography is not necessary. The treatment of ...