Two adult cases of extralobar pulmonary sequestration : a non-complicated case and a necrotic case with torsion

Background: This case report describes two cases of extralobar pulmonary sequestration in adults with and without torsion/necrosis. Case Report: Non-complicated extralobar pulmonary sequestration was found incidentally in a 50-year-old asymptomatic woman (Case 1), diagnosed with the presence of a branching structure in a mass lesion and blood supply from the right inferior phrenic artery. Another case of a 38-year-old woman presented with a sudden onset of back pain caused by extralobar pulmonary sequestration with torsion/necrosis (Case 2). A 4-cm fusiform mass in the paravertebral region showed enhancement in the peripheral rim only, and no feeding artery. These were the same as it had been reported typical findings in extralobar pulmonary sequestration with necrosis. On magnetic resonance imaging, the masses in both cases showed inhomogeneous low signal and branching high signal on T2-weighted images. That was characteristic for a stroma without dilated alveoli as a solid part and dilated alveoli as fluid regions. Conclusions: By comparing those two cases, we came to a conclusion that only T2-weighted imaging reflects the native structure, even after infarction. Although differentiation from a cystic tumor with hemorrhage or infection can be problematic, inhomogeneous low signal and branching high signal on T2-weighted images may help us distinguish extralobar pulmonary sequestration from other cystic lesions.