Soft Tissue Special Issue: Cutaneous Pleomorphic Spindle Cell Tumors.

This manuscript provides an overview of pleomorphic spindle cell tumors presenting on sun-damaged skin of the elderly and includes discussions of atypical fibroxanthoma, pleomorphic dermal sarcoma, spindle cell and metaplastic squamous cell carcinoma, spindle cell and dedifferentiated melanoma and poorly differentiated cutaneous angiosarcoma. These tumors share many of the clinical presenting and histological features, making confident diagnosis challenging. A reliable and robust diagnosis is necessary to predict behavior as the biologic potential of these tumors ranges from benign (e.g. atypical fibroxanthoma) to outright malignant with poor survival rates (e.g. cutaneous angiosarcoma). The salient clinical, histologic and immunohistochemical characteristics are discussed in detail with emphasis on distinguishing features and differential diagnosis to provide the reader with a better understanding of these entities and helpful clues for a more robust diagnosis.