Bronchogenic sequestration is seen in which lobe -

Bronchogenic sequestration refers to the presence of a discrete mass of lung tissue without any normal connection to the airway system. Intralobar sequestrations are found most frequently in the posterior basal segment of the left lower lobe. Blood supply to the sequestered area arises not from the pulmonary arteries but from the aorta or its branches. Extralobar sequestrations are external to the lung. Found most commonly in infants as abnormal mass lesions, they may be associated with other congenital anomalies. Intralobar sequestrations are found within the lung substance and are usually associated with recurrent localized infection or bronchiectasis.