Spindle cell lesions--neoplastic or non-neoplastic?: spindle cell carcinoma and other atypical spindle cell lesions of the head and neck.

One challenging feature of head and neck pathology is that a dizzying array of spindle cell lesions occur here ranging all the way from reactive to malignant and very aggressive. This makes accurate diagnosis critical. At mucosal sites, the most important of these is spindle cell carcinoma (SpCC). Most SpCC are overtly malignant, and the differential diagnosis then includes a number of different malignant spindle cell neoplasms. However, there are several benign or even non-neoplastic lesions that can sometimes be difficult to discern from SpCC. The pathologic and clinical features can resolve this differential diagnosis. This review will focus on the clinical and diagnostic features of SpCC and the select non-neoplastic or benign lesions which are occasionally hard to distinguish from it.