Case report: unilateral absence of the left pulmonary artery with left gastric artery collateral supply and hematologic disorder.

Unilateral absence of the pulmonary artery is a congenital disorder resulting from malformation of the sixth aortic arch during embryogenesis. This case report presents a unique instance of unilateral absence of the pulmonary artery, incidentally discovered in an individual with multiple myeloma. Despite a history of recurrent childhood pulmonary infections, the patient remained asymptomatic until presenting with symptoms of myeloma. Imaging revealed a right-sided aortic arch, absent left pulmonary artery, and left lung atrophy with atelectasis. Among various collateral arteries, a notable finding in this case is the left gastric artery supplying the left lower lobe.