IS case 482: Pectus excavatum deformity
Imaging Sciences URMC 2010
Publication Date: 2010-08-30
Patient is a 60-year-old woman noted to have mass effect on the right side of the heart described in cardiology angiogram report. Evaluation requested to rule out cardiac mass. Patient has stable chronic heart disease symptoms; no acute symptoms at time of exam.
PA and lateral views of the chest were obtained; frontal view demonstrated deviation of the cardiac silhouette to the left with obliteration of the right heart border. Lateral view demonstrated prominent appearance of sternum projecting posteriorly in the chest, a classic example of severe pectus excavatum deformity of the sternum. Exam was unchanged from comparison exams dating back several years.
Pectus excavatum deformity, defined as projection of the ribs anterior to a depressed sternum in the lateral projection, is a condition that exists in a continuum from an incidentally noted variant to a pathological condition in which surgical intervention may be required. The pectus index is a measure of the degree of sternal depression, and is calculated by dividing the transverse diameter of the chest by the AP dimension of the chest as measured from the posterior aspect of the sternum to the posterior chest wall. Classically, an index of greater than 3.25, usually determined by CT or MR imaging, suggests a need for further investigation and possible surgical intervention. In addition to the lateral radiographic signature of the sternum projecting posteriorly in the region of the anterior mediastinum, other radiographic hallmarks include displacement of the cardiac silhouette to the left with possible spurious cardiomegaly due to rotation and obliteration of the right heart border. Pectus excavatum is the most common chest wall abnormality, affecting 1 in 300-400 live births, although many of these are mild and asymptomatic. Severe cases are associated with mitral valve prolapse (up to 20 - 60% of cases) and decreased exercise tolerance with costochondral pain. A positive family history is present in up to 35% of patients with a 4:1 male:female ratio.
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