Spindle cell tumors of the mediastinum

Spindle cell tumors originating in the mediastinum are extremely rare. Due to the profusion of structures and organs located in the mediastinum, a wide variety of spindle cell neoplastic processes can develop in this location. These include various different tumor types including epithelial, vascular, lipomatous, fibroblastic and neural tumors among others. Many of these different tumor types are associated with specific immunohistochemical and molecular genetic profiles that help differentiate them from each other. Although spindle cell morphology has traditionally been associated with mesenchymal neoplasms, in the mediastinum the most common spindle cell tumor is spindle cell thymoma, an epithelial rather than mesenchymal neoplasm. Except for neurogenic tumors originating in the posterior mediastinum, mesenchymal neoplasms are quite rare in mediastinal locations and require clinical correlation to rule out the possibility of a metastasis from an extra-mediastinal soft tissue or somatic sarcoma. Herein we will review the most common types of spindle cell neoplasms that occur in the mediastinum, with particular emphasis in their differential diagnosis and the role of ancillary techniques for diagnosis.