Which finding is associated with the egg in cup sign?

The egg in cup sign is a characteristic radiological finding that is specifically associated with constrictive pericarditis. This sign refers to the appearance of the heart silhouette on chest X-ray, where the heart resembles an egg sitting within a cup, indicating that the heart is constrained by the fibrotic or thickened pericardial sac, leading to impaired diastolic filling.

In constrictive pericarditis, the thickened pericardium restricts the heart's ability to expand fully during diastole, which results in characteristic changes in heart size and shape visible on imaging. This contrasts with other conditions listed, where the heart's appearance on imaging would differ significantly due to their unique pathophysiological processes.

With constrictive pericarditis, the heart is often smaller due to this restriction, leading to the classic "egg in cup" appearance. Other choices present different cardiac conditions, each associated with their own distinct imaging signs and symptoms, but none fit the specific morphology depicted in the radiological finding of the egg in cup sign as accurately as constrictive pericarditis does.