spindle cell tumor differential diagnosis：Spindle Cell Lesions—Neoplastic or Non

Discussion Spindle Cell Carcinoma

SpCC is a variant of squamous cell carcinoma which has spindled or pleomorphic tumor cells which simulate a true sarcoma but are epithelial in nature. For years, the true pathophysiology of this spindled component was debated, leading to numerous alternate terms, including carcinosarcoma, pseudosarcoma, pleomorphic carcinoma, and metaplastic carcinoma, among others [1]. Many different theories to explain the morphology were put forward in the past, including divergent differentiation of carcinoma cells, so-called “collision” tumors where there are two separate neoplastic clones combined in the same lesion, and the concept that squamous carcinoma “drives” the proliferation of a pseudosarcomatous stromal response. Over time, numerous studies analyzing the morphologic [2], immunohistochemical [1, 3, 5–8], ultrastructural [8], and molecular [9] features of SpCC have shown epithelial characteristics in the spindle cell population as well as marked geneti...