title: Regression of an enchondroma: a case report and proposed etiology.
abstract: Enchondromas are common benign bone lesions that are found in the medullary cavity of tubular bones, usually at the metaphysis. Regression is highly unusual, and loss of matrix mineralization in an existing enchondroma should prompt investigation for malignant transformation. We present the case of a 50-year-old woman with an enchondroma of the proximal humeral metadiaphysis, which underwent loss of matrix mineralization that corresponded to replacement with marrow fat on MRI. This transformation of the cartilage tumor matrix into normal bone marrow may occur in a process similar to that seen with endochondral ossification.
authors.affiliation: Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1400 Pressler Street, Unit 1475, Houston, TX, 77030, USA, asensarma@mdanderson.org.
authors.forename: Anirban
authors.initials: A
authors.lastname: Sensarma
authors.forename: John E
authors.initials: JE
authors.lastname: Madewell
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Meis
authors.forename: Rajendra
authors.initials: R
authors.lastname: Kumar
authors.forename: Patrick P
authors.initials: PP
authors.lastname: Lin
authors.forename: Behrang
authors.initials: B
authors.lastname: Amini
mesh_terms: D001859:Bone Neoplasms / Q000175:diagnosis*; D002812:Chondroma / Q000175:diagnosis*; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D009365:Neoplasm Regression, Spontaneous / Q000473:pathology*