Pulmonary Sequestration

David Rubay

Pulmonary sequestration is a mass of nonfunctioning lung tissue with no communication with the tracheobronchial tree (Figure 35.1).
This sequestered mass of lung tissue receives its blood supply anomalously from the systemic circulation.
Pulmonary sequestration appears to result from abnormal budding of the primitive foregut.¹
The tissue in this accessory lung bud migrates with the developing lung but does not communicate with it.
It receives its blood supply from vessels that connect to the aorta or one of its side branches.
The arterial supply is derived in most cases from the thoracic aorta (75%) or the abdominal aorta (20%).¹
In some cases (15%), 2 different arteries supply the blood.

EPIDEMIOLOGY AND ETIOLOGY

Incidence: Pulmonary sequestration represents approximately 6% of all congenital pulmonary malformations.

Types:
- Intrapulmonary sequestrations are the most common form, and 60% of these are found in the posterior basal segment of the left lower lobe. Overall, 98% occur in the lower lobes.
  - Bilateral involvement is uncommon.
  - About 10% of cases may be associated with other congenital anomalies.
- Extrapulmonary sequestrations occur on the left in 95% of cases.¹,²,³
  - Of these, 75% are found in the costophrenic sulcus on the left side.
  - They may also be found in the mediastinum, pericardium, and within or below the diaphragm.
  - They are associated with other congenital malformations in more than 50% of cases, such as congenital diaphragmatic hernias, congenital pulmonary airway malformation (CPAM) type II (hybrid lesions), and congenital heart disease.¹,⁴,⁵,⁶
Sex: In the extrapulmonary form, males are affected approximately 4 times more often than females.⁷
Incidence is equal in males and females in the intrapulmonary type.
Age: More than one half of intrapulmonary sequestrations are diagnosed in later childhood or even in adulthood.⁷
Neonates and infants are usually asymptomatic. More than one half of extrapulmonary sequestrations are diagnosed in patients younger than 1 year.
Often, this is because other congenital anomalies are present, including congenital diaphragmatic hernia, cardiac malformations, and GI malformations.⁷,⁸

Figure 35.1 Diagrammatic representation of 2 types of pulmonary sequestration. A, Intralobar pulmonary sequestrations are lesions mostly confined to the lower lobes, intimately connected with the adjacent lung, usually having venous drainage through the pulmonary veins and no separate pleural covering. B, Extralobar pulmonary sequestrations are accessory lobes with separate pleural covering and have an anomalous venous drainage through a systemic vein. (Reprinted with permission from Lee EY. Pediatric Radiology: Practical Imaging Evaluation of Infants and Children. Philadelphia, PA: Wolters Kluwer; 2018.)

Only gold members can continue reading. Log In or Register to continue