Parosteal lipoma of the thigh with cartilaginous and osseous differentiation: an osteochondrolipoma.
Lipomas are very common benign soft tissue neoplasms. They are usually slow-growing and may occur anywhere in the body. Mature cartilage and bone arising in a lipoma is a rare event and is mostly associated with a parosteal localization of the neoplasm. We describe a new case of osteochondrolipoma showing not only major adipocytic differentiation but also areas of fibrocytic and cartilaginous cell differentiation and bone formation (both endochondral and membranous). The occurrence of at least 4 distinct directions of mesenchymal cell differentiation within a benign neoplasia underlines the concept of multilineage differentiation of pluripotent mesenchymal stem cells. Such a multidirectional potential was recently well established in vitro in stem cells present in adult adipocytic tissue.
Rau
Tilman
T
Department of Pathology, Friedrich-Alexander University of Erlangen-Nuremberg, D-91054 Erlangen, Germany. tnrau@parho.imed.uni-erlangen.de
Soeder
Stephan
S
Olk
Alexander
A
Aigner
Thomas
T
D017667:Adipocytes / Q000473:pathology; D000368:Aged; D001842:Bone and Bones / Q000473:pathology*; D002356:Cartilage / Q000473:pathology*; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D008067:Lipoma / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000473:pathology; D009999:Ossification, Heterotopic / Q000473:pathology; D010521:Periosteum / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000473:pathology*; D013848:Thigh