title: Angiomatoid fibrous histiocytoma of bone: a calcifying sclerosing variant mimicking osteosarcoma.
abstract: Angiomatoid fibrous histiocytoma is a neoplasm of uncertain histogenesis, which most commonly arises in the subcutaneous tissue of the extremities of children and young adults. We report the first case of a calcifying sclerosing variant of this entity. This case arose in bone-a site where there has been just 1 previously published case of typical (nonsclerosing/mineralizing) angiomatoid fibrous histiocytoma. The patient presented with the classical paraneoplastic syndrome that can occur with this tumor type and, apart from the described extracellular matrical features, displayed typical histologic features. Due to the rarity of angiomatoid fibrous histiocytoma at this site and the presence of matrical sclerosis/mineralization, this case raised the important differential diagnosis of osteosarcoma, both histologically and radiologically. The diagnosis was confirmed by molecular analysis; fluorescence in situ hybridization for EWSR1 gene disruption, and reverse transcription-polymerase chain reaction using newly designed primers on both frozen and decalcified, paraffin-embedded tissue samples showing an EWSR1-ATF1 translocation. It is important to recognize that this relatively indolent tumor can arise in bone and that it can contain focally mineralized hyalinized sclerotic matrix to avoid making the serious misdiagnosis of high-grade osteosarcoma and administering aggressive systemic chemotherapeutic treatment.
authors.affiliation: Department of Musculoskeletal Pathology, Robert Jones & Agnes hunt Orthopaedic Hospital NHS Trust, Oswestry, Shropshire SY10 7AG, UK. chas.mangham@rjah.nhs.uk
authors.forename: David Chas
authors.initials: DC
authors.lastname: Mangham
authors.forename: Ann
authors.initials: A
authors.lastname: Williams
authors.forename: Radhesh K
authors.initials: RK
authors.lastname: Lalam
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Brundler
authors.forename: Michael G
authors.initials: MG
authors.lastname: Leahy
authors.forename: Wim Paul
authors.initials: WP
authors.lastname: Cool
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D001859:Bone Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D002114:Calcinosis / Q000473:pathology; D002467:Cell Nucleus / Q000473:pathology; D002648:Child; D003937:Diagnosis, Differential; D018572:Disease-Free Survival; D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008938:Mitosis; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D012516:Osteosarcoma / Q000175:diagnosis*; D012598:Sclerosis / Q000473:pathology; D014157:Transcription Factors / Q000235:genetics; D014178:Translocation, Genetic; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; C111598:EWS-ATF1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors