Keloid and Cellular Scar David S. Cassarino, MD, PhD Key Facts Terminology Scar with prominent thickened and eosinophilic bundles of collagen Clinical Issues Persistence and recurrence are common, but no…

Pleomorphic Liposarcoma Thomas Mentzel, MD Key Facts Terminology Pleomorphic high-grade sarcoma containing variable amounts of pleomorphic lipoblasts Clinical Issues Rarest subtype of liposarcoma Accounts for approximately 5% of all liposarcomas…

Mixed Liposarcoma Thomas Mentzel, MD Key Facts Terminology Liposarcoma showing morphologic/genetic features of combined myxoid liposarcoma and atypical lipomatous tumor/dedifferentiated liposarcoma, or of myxoid liposarcoma and pleomorphic liposarcoma Clinical Issues…

Myxoid Liposarcoma Thomas Mentzel, MD Key Facts Terminology Malignant lipogenic neoplasm composed of primitive nonlipogenic mesenchymal cells and variable number of lipoblasts set in myxoid stroma with characteristic branching blood…

Dedifferentiated Liposarcoma Thomas Mentzel, MD Key Facts Terminology Malignant lipogenic neoplasm showing abrupt or gradual transition from atypical lipomatous tumor to nonlipogenic sarcoma of variable histology Clinical Issues Retroperitoneum, intraabdominal…

Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma Thomas Mentzel, MD Key Facts Terminology Intermediate (locally aggressive, nonmetastasizing) lipogenic neoplasm composed of atypical adipocytes Clinical Issues Accounts for 40-45% of all liposarcomas Occurs most…

Chondroid Lipoma Khin Thway, BSc, MBBS, FRCPath Key Facts Terminology Uncommon benign neoplasm with features of embryonal fat and embryonal cartilage Balanced translocation t(11;16)(q13; p12-13) in 2 cases, thought to…

Lipoblastoma and Lipoblastomatosis Amitabh Srivastava, MD Key Facts Terminology Benign tumor resembling fetal adipose tissue Lipoblastomas are well circumscribed Lipoblastomatosis is deeply infiltrative Clinical Issues Presents in infancy and early…

Spindle Cell/Pleomorphic Lipoma Amitabh Srivastava, MD Key Facts Terminology Benign adipocytic tumor with variable admixture of spindle cells, ropey collagen, and multinucleate tumor giant cells Clinical Issues Typically in older…

Hibernoma Khin Thway, BSc, MBBS, FRCPath Key Facts Terminology Benign tumor with differentiation toward brown fat, most frequently seen in younger adults Clinical Issues Peak incidence in 3rd decade Most…