Malignant fibrous histiocytoma and fibrosarcoma of bone: a re-assessment in the light of currently employed morphological, immunohistochemical and molecular approaches

Low-grade myxofibrosarcoma following a metal implantation in femur: a case report

Myxofibrosarcoma is a myxoid variant of malignant fibrous histiocytoma that most commonly involves the extremities of elderly people. However, a primary myxofibrosarcoma with bone invasion in young adults is extremely rare. Herein, we report the case of a 31-year-old male with a gradually enlarging left thigh mass, who had a history of left femur fracture and received an open reduction and internal fixation with titanium alloy plates and screws 33 months previously. Imaging investigations revealed an irregularly shaped soft tissue mass around the left femur shaft and a partial bone defect in the middle one-third of the left femur. Pathological examination of the resected specimen showed a multi-nodular appearance, abundant myxoid matrix and elongated curvilinear capillaries. Immunohistochemical studies revealed that the tumor cells was positive for VIM and MDM2, and was negative for CK, MSA, SMA, DES, S-100 and CD34. Labeling index of Ki-67 was 25%. Based on the morphological finding and immunostaining, it was diagnosed as a low-grade myxofibrosarcoma. The clinical and imaging examinations did not reveal the evidence of a primary cancer elsewhere, and the patient had no personal or family history of malignancy. To our knowledge, this is the first case of a primary myxofibrosarcoma developed following a fracture and metal implantation in young adults.

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Mapping protein signal pathway interaction in sarcoma bone metastasis: linkage between rank, metalloproteinases turnover and growth factor signaling pathways

We applied reverse phase protein microarrays technology to map signal pathway interactions in a discovery set of 34 soft tissue sarcoma (STS) bone metastases compared to healthy bone. Proteins associated with matrix remodeling (MMP), adhesion (FAK Y576/577, Syndecan-1), and growth/survival (IGF1R Y1135/1136, PI3K, EGFR) were elevated in metastasis compared to normal bone. Linkage between Syndecan-1, FAK Y576/577, Shc Y317, and EGFR, IGF Y1135/1136, PI3K/AKT was a prominent feature of STS bone metastasis. Elevated linkage between RANKL and 4EBP1 T37/46, EGFR, IGF1R Y1135/1136, Src Y41, Shc Y317, PI3Kp110γ was associated with short survival. Finally, we tested the hypothesis that signal pathway proteins augmented in the STS bone metastasis may provide clues to understand the subset of primary STS that metastasize. The most representative molecules identified in the discovery set were validated on an independent series of 82 primary STS by immunohistochemistry applied to a tissue microarray. The goal was to correlate the molecular profile in the primary tumors with a higher likelihood of metastasis. Elevation of activated kinase substrate endpoints IRS1 S612, 4EBP1 T37/46, FAK Y576/577 and loss of Fibronectin, were associated with a higher likelihood of metastases. These data indicate that the linkage between matrix remodeling, adhesion, and growth signaling may drive STS metastasis and can be the basis for prognostic and therapeutic strategies.