Update on Lipomatous Tumors with Emphasis on Emerging Entities, Unusual Anatomic Sites, and Variant Histologic Patterns.

This article reviews the histologic patterns of spindle cell/pleomorphic lipoma, well-differentiated liposarcoma, and dedifferentiated liposarcoma in the context of both usual and atypical anatomic presentation. The utility of molecular and immunohistochemical diagnostic modalities to distinguish these entities is described. In addition, more recently described and controversial entities, including atypical spindle cell lipomatous tumor and anisometric cell lipoma, are discussed.