The histomorphologic spectrum of spindle cell thymoma.

Spindle cell thymomas are a subset of thymoma that is characterized by great morphologic variability. This histologic complexity coupled with the overall rarity of these lesions can easily cause diagnostic confusion with other spindle cell neoplasms of the anterior mediastinum. In this review, we summarize the various morphologic patterns that have been described in the peer-reviewed literature and present additional patterns that we have encountered in our practice. Familiarity with the histomorphologic spectrum of spindle cell thymomas is essential to diagnose these tumors correctly and distinguish them from other mediastinal spindle cell lesions that require different treatment modalities.