Pulmonary sequestration (intralobar)

Intralobar pulmonary sequestration (ILS) is a subtype of pulmonary sequestration. 

Clinical presentation

Patients usually present before the third decade with recurrent infection.

Pathology

It is the commoner type of pulmonary sequestration (four times commoner than extralobar sequestration), accounting for 75% of all sequestrations and is characterized by the sequestration surrounded by normal lung tissue without its own pleural covering.

There is increasing data to support the concept of sequestrations stemming from recurrent infections that produce aberrant arterial vessels arising from the aorta ⁶. Feeding vessels include branches from the thoracic aorta (75%), abdominal aorta, intercostal artery or multiple arteries. Venous drainage commonly occurs via the pulmonary venous system.

Location

There is strong predilection towards the lower lobes (predominantly left lower lobe).

Treatment and prognosis

Surgical excision is the mainstay of treatment.

Differential diagnosis

On imaging, possible differential considerations include:

• congenital pulmonary airway malformation
• neuroblastoma
• bronchogenic cyst
• bronchiectasis (in infected ILS)