Anne-Valérie Decouvelaere

Aims: Myxomas are benign soft tissue neoplasms typically driven by activating GNAS mutations. However, a subset lacks this alteration and remains molecularly undefined. Recent reports have implicated MAP3K family gene fusions in rare myxoid neoplasms sharing features with myxoma. Methods and results: In this study, we characterise 39 MAP3K ‐rearranged myxoid tumours by integrating clinical, histopathological, immunohistochemical and molecular data. The cohort comprised predominantly middle‐aged adults, with tumours distributed across a wide anatomic range (limbs, trunk, face), often in superficial locations. Histologically, the tumours were composed of bland spindle or histiocytoid cells embedded in an abundant myxoid stroma with features mimicking cellular myxoma, such as intermediate‐to‐high cellularity and broad fibrous septa. High‐grade pleomorphism and necrosis were consistently absent. Immunohistochemistry revealed frequent CD34 and HMGA2 positivity, a low Ki‐67 proliferation index, and preserved PRKAR1A expression. RNA sequencing identified diverse MAP3K gene fusions, most notably MSI2 :: MAP3K3 and MAP3K8 :: MAP3K3 , alongside several unique fusion partners. Transcriptomic clustering demonstrated a relationship between MAP3K ‐rearranged tumours, GNAS ‐mutant myxomas and a proximity with myxofibrosarcomas, while clearly distinguishing them from other myxoid sarcomas. Clinical follow‐up indicated an indolent course with no evidence of metastasis and rare local recurrences; notably, one patient with positive surgical margins remained disease‐free several years postoperatively. Conclusion: MAP3K ‐rearranged myxoid tumours represent a molecularly distinct subset of benign neoplasms that overlap histologically with cellular myxoma and must be distinguished from low‐grade myxofibrosarcoma.

Epithelioid hemangioendothelioma is a rare connective tissue tumor of vascular origin. It is most commonly found in young to middle aged women, and its clinical behavior is remakably variable from an indolent metastatic tumor to an aggressive rapidly growing neoplasm. Most tumors are diagnosed in an advanced unresectable phase and when clinically aggressive, require systemic cytotoxic treatment of sarcoma. Then, the 5-year survival rate after chemotherapy does not exceed 30%. Antiangiogenics are active in selected sarcoma subtypes: pazopanib, the only anti angiogenic registered agent for sarcoma provides a median PFS of 4.5 months only in the pivotal study. Their activity in EHE has been reported but long term outcome of these patients remain unreported. We report a case of a female patient with HEH who was treated with pazopanib for almost 8 years. Pazopanib therapy resulted in clinical improvement of symptoms and durable stabilization of liver tumors and lung lesions. Conclusion: Pazopanib is a promising therapeutic option in patients with HEH.

Angiosarcomas are rare aggressive neoplasms that can occur secondary to chronic lymphedema (Stewart-Treves syndrome). Although secondary angiosarcomas are commonly described after-mastectomy and/or after-radiotherapy, few cases have been reported in association with chronic lymphedema of congenital origin. We report the clinical, pathological, and cytogenetic findings in a case of cutaneous epithelioid clear cells angiosarcoma that occurred in a 21-year-old woman with hemibody congenital lymphedema. Surgical biopsies of the tumor mass revealed diffuse epithelioid proliferation of clear atypical cells, for which immunophenotyping highlighted the vascular differentiation. Despiteen blocresection of the tumor, the patient died of metastatic disease three months after diagnosis. This case illustrates the clinical and pathology characteristics of angiosarcoma that is a rare entity secondary to chronic lymphedema. It is the first reported case for which thec-MYCamplification status was assessed. The diagnostic value of this amplification should be further evaluated in this specific context.

Solitary fibrous tumors (SFTs) are rare spindle-cell tumors. Their cell-of-origin and molecular basis are poorly known. They raise several clinical problems. Differential diagnosis may be difficult, prognosis is poorly apprehended by histoclinical features, and no effective therapy exists for advanced stages. We profiled 16 SFT samples using whole-genome DNA microarrays and analyzed their expression profiles with publicly available profiles of 36 additional SFTs and 212 soft tissue sarcomas (STSs). Immunohistochemistry was applied to validate the expression of some discriminating genes. SFTs displayed whole-genome expression profiles more homogeneous and different from STSs, but closer to genetically-simple than genetically-complex STSs. The SFTs/STSs comparison identified a high percentage (∼30%) of genes as differentially expressed, most of them without any DNA copy number alteration. One of the genes most overexpressed in SFTs encoded the ALDH1 stem cell marker. Several upregulated genes and associated ontologies were also related to progenitor/stem cells. SFTs also overexpressed genes encoding therapeutic targets such as kinases (EGFR, ERBB2, FGFR1, JAK2), histone deacetylases, or retinoic acid receptors. Their overexpression was found in all SFTs, regardless the anatomical location. Finally, we identified a 31-gene signature associated with the mitotic count, containing many genes related to cell cycle/mitosis, including AURKA. We established a robust repertoire of genes differentially expressed in SFTs. Certain overexpressed genes could provide new diagnostic (ALDH1A1), prognostic (AURKA) and/or therapeutic targets.

Although the management of sarcoma is improving, non adherence to clinical practice guidelines (CPGs) remains high, mainly because of the low incidence of the disease and the variety of histological subtypes. Since little is known about the health economics of sarcoma, we undertook a cost-effectiveness analysis (within the CONnective TIssue CAncer NETwork, CONTICANET) comparing costs and outcomes when clinicians adhered to CPGs and when they did not. Patients studied had a histological diagnosis of sarcoma, were older than 15 years, and had been treated in the Rhône-Alpes region of France (in 2005/2006) or in the Veneto region of Italy (in 2007). Data collected retrospectively for the three years after diagnosis were used to determine relapse free survival and health costs (adopting the hospital's perspective and a microcosting approach). All costs were expressed in euros (€) at their 2009 value. A 4% annual discount rate was applied to both costs and effects. The incremental cost-effectiveness ratio (ICER) was expressed as cost per relapse-free year gained when management was compliant with CPGs compared with when it was not. To capture uncertainty surrounding ICER, a probabilistic sensitivity analysis was performed based on a non-parametric bootstrap method. A total of 219 patients were included in the study. Compliance with CPGs was observed for 118 patients (54%). Average total costs reached 23,571 euros when treatment was in accordance with CPGs and 27,313 euros when it was not. In relation to relapse-free survival, compliance with CPGs strictly dominates non compliance, i.e. it is both less costly and more effective. Taking uncertainty into account, the probability that compliance with CPGs still strictly dominates was 75%. Our findings should encourage physicians to increase their compliance with CPGs and healthcare administrators to invest in the implementation of CPGs in the management of sarcoma.

Assessment of osteosarcoma response to neoadjuvant chemotherapy is performed by histopathologic analysis after surgical resection of the primary tumor. The purpose of this study was to evaluate whether (18)F-FDG PET could be a noninvasive surrogate to histopathologic analysis and allow for earlier response evaluation to neoadjuvant chemotherapy in osteosarcoma. Metabolic response to neoadjuvant chemotherapy was assessed in immunocompetent rats with a preestablished orthotopic osteosarcoma using (18)F-FDG PET before and after receiving 2 doses of ifosfamide. Comparison was then made by assessing histologic responses on euthanized animals. Maximum standardized uptake value (SUVmax) measured by (18)F-FDG PET after 2 doses of chemotherapy was correlated to histologic classification (P < 0.01). An SUVmax less than 15 corresponded to good responders, whereas an SUVmax greater than 15 but less than 20 and an SUVmax greater than 20 corresponded to partial responders or nonresponders, respectively. A 40% decrease in SUVmax between the first and second (18)F-FDG PET scans distinguished between partial and good response to chemotherapy. Determination of SUVmax using semiquantitative (18)F-FDG PET predicts response to neoadjuvant chemotherapy earlier than does histologic analysis.