Atypical extralobar sequestration: CT-pathological correlation

Pulmonary sequestration is a malformation comprised of dysplastic lung tiss ue without normal communication with the tracheobronchial tree and with an anomalous systemic arterial supply. Pulmonary sequestration is classified i nto two types, intralobar and extralobar based on the location of the malfo rmation and the venous drainage. Extralobar sequestration is less common th an intralobar sequestration and usually has systemic venous drainage into t he azygos system. Most patients with extralobar sequestration are diagnosed before the age of 10. We present an interesting and unusual case of extral obar sequestration which presented as a retroperitoneal mass in an asymptom atic adult. (C) Elsevier Science Inc., 1999.