The "Line Sign" Is a Rapid and Efficient Diagnostic "Test" for Morphea: Clinicopathological Study of 73 Cases.

Histologic clues that facilitate rapid diagnosis of morphea at scanning magnification have been described but not well studied. We examined 73 cases of morphea and 42 control cases to determine the sensitivity and specificity of a novel histopathological feature-"the line sign (LS)"-a prominent, straight interface between subcutis and adjacent collagen. The sensitivity of LS was shown to be the most sensitive feature among 4 other existing histopathological features. Its specificity, however, was not the highest among the other features and needs to be evaluated further in future studies to confirm the usefulness of LS as a diagnostic tool for morphea.