The medial breast margin sign: A new sign of pectus excavatum in adult females and comparison with classic signs.

Introduction: Pectus excavatum (PX) denotes a concavity of the sternum and is the most common chest wall deformity. Many characteristic signs have been described on frontal chest radiographs including increased density of the inferomedial right lung, blurring of the right heart border, steeply angled anterior ribs, horizontal posterior ribs, straight or convex left heart border and loss of silhouette of the descending thoracic aorta. These signs are often subtle and rarely all present in any individual. We describe a further sign in women with PX, the medial breast margin sign. This sign consists of more sharply defined and more vertically oriented medial breast borders on frontal chest radiographs than in those of women with normal chest wall morphology. This study aims to document the sensitivity, specificity and inter-observer reliability of the new sign, and compare with that of the previously described signs in patients with varying degrees of PX.

Methods: The frontal chest radiographs of 185 women with PX and 50 women with normal chest wall morphology were assessed by two reviewers for the presence of the new sign and previously described signs. All the signs had their sensitivity, specificity and inter-observer reliability calculated.

Results: The new sign had a sensitivity of 0.48, a specificity of 0.96 and inter-observer reliability of κ = 0.79, ranking third, second and first among all other signs, respectively.

Conclusion: The medial breast margin sign is useful in diagnosing PX and is comparable to the previously described classic signs.