title: Low-grade fibromyxoid sarcoma with prominent giant rosettes and heterotopic ossification.
abstract: Low-grade fibromyxoid sarcoma is a rare soft tissue sarcoma of fibroblastic differentiation characterized by a deceptively benign morphologic appearance with almost consistent MUC4 expression and recurrent chromosomal translocations, t(7;16)(q34;p11) and t(11;16)(p11;p11), resulting in the FUS-CREB3L2 and FUS-CREB3L1 fusion genes, respectively. A subset of the tumors show peculiar histologic features, designated as giant rosettes, and were formerly referred to as hyalinizing spindle cell tumor with giant rosettes. We herein report a case of low-grade fibromyxoid sarcoma showing the presence of numerous giant rosettes, with and without collagenous centers, distributed throughout the lesion and unusual rim-like heterotopic ossification. Such a case might present a diagnostic challenge. The diagnosis of the tumor was confirmed by positive immunoreactivity to MUC4 and the FUS-CREB3L2 fusion detected by molecular testing using formalin-fixed, paraffin-embedded tissue. This case, which has such unusual clinicopathologic features, would help to further expand our knowledge regarding the morphologic diversities of low-grade fibromyxoid sarcoma.
authors: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan. hisaoka@med.uoeh-u.ac.jp
authors: Masanori
authors: M
authors: Hisaoka
authors: Atsuji
authors: A
authors: Matsuyama
authors: Takatoshi
authors: T
authors: Aoki
authors: Akio
authors: A
authors: Sakamoto
authors: Koichiro
authors: K
authors: Yokoyama
mesh_terms: D000328:Adult; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D004252:DNA Mutational Analysis; D005260:Female; D005354:Fibrosarcoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D050939:Gene Fusion; D006801:Humans; D055264:Mucin-4 / Q000378:metabolism; D009999:Ossification, Heterotopic / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D034702:RNA-Binding Protein FUS / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; C518609:CREB3L2 protein, human; C524658:MUC4 protein, human; D055264:Mucin-4; D034702:RNA-Binding Protein FUS; D003094:Collagen