MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): A multicenter correlative MRI-pathology study of 21 cases and literature review

Objective. To evaluate MR imaging and pathology findings in order to define the characteristic features of clear cell sarcoma of the soft tissues (malignant melanoma of the soft parts). Design and patients. MR examinations of 21 patients with histologically proven clear cell sarcoma of the musculoskeletal system were retrospectively reviewed and assessed for shape, homogeneity, delineation, signal intensities on T1- and T2-weighted images, contrast enhancement, relationship with adjacent fascia or tendon, secondary bone involvement, and intratumoral necrosis. In 19 cases the pathology findings were available for review and for a comparative MR-pathology study. Results. On T1-weighted images, lesions were isointense (n=3), hypointense (n=7) or slightly hyperintense to muscle (n=11). Immunohistochemical examination was performed in 17 patients. All 17 specimens showed positivity for HMB-45 antibody. In nine of 11 lesions with slightly increased signal intensity on T1-weighted images, a correlative MR imaging-pathology study was possible. All nine were positive to HMB-45 antibody. Conclusions. Clear cell sarcoma of the musculoskeletal system often has a benign-looking appearance on MR images. In up to 52% of patients, this lesion with melanocytic differentiation has slightly increased signal intensity on T1-weighted images compared with muscle. As the presence of this relative higher signal intensity on T1-weighted images is rather specific for tumors displaying melanocytic differentiation, radiologists should familiarize themselves with this rare entity and include it in their differential diagnosis when confronted with a well- defined, homogeneous, strongly enhancing mass with slightly higher signal intensity compared with muscle on native T1-weighted images

The role of EXT1 in nonhereditary osteochondroma: Identification of homozygous deletions

Background: Multiple osteochondromas is a hereditary syndrome that is characterized by the formation of cartilagecapped bony neoplasms (osteochondromas), for which exostosis (multiple)-1 (EXT1) has been identified as a causative gene. However, 85% of all osteochondromas present as solitary (nonhereditary) lesions in which somatic mutations in EXT1 are extremely rare, but loss of heterozygosity and clonal rearrangement of 8q24 (the chromosomal locus of EXT1) are common. We examined whether EXT1 might act as a classical tumor suppressor gene for nonhereditary osteochondromas. Methods: Eight nonhereditary osteochondromas were subjected to high-resolution array-based comparative genomic h

A phase II study of gefitinib for patients with advanced HER-1 expressing synovial sarcoma refractory to doxorubicin-containing regimens

Rationale. Advanced synovial sarcomas (SyS) refractory to doxorubicin and ifosfamide are highly resistant to the currently available cytotoxic agents. Based on a report showing a specific overexpression of HER-1 in SyS, we investigated an HER-1 inhibitor, gefitinib, in refractory SyS. Subjects and Methods. To establish the efficacy and safety of gefitinib in HER-1 -positive SyS refractory to one or two lines of doxorubicin- and ifosfamide-based chemotherapy, a phase II study was conducted from December 2002 to October 2005 by 12 centers of the European Organization for Research and Treatment of Cancer Soft Tissue and Bone Sarcoma Group. Gefitinib was given at a 500-mg/day oral dose until progression or intolerance. Results. Forty-eight patients were included (46 eligible). All patients had previously received chemotherapy for metastatic disease, with a median number of two lines (range, 1-4). The most frequent metastatic sites were the lungs (n = 44, 92%), lymph nodes (n = 11, 23%), and soft tissues (n = 10, 21%). The median duration of treatment was 43 days (range, 13-315). Treatment was interrupted in five patients (10%). Treatment was halted for progression in 45 (94%) patients. The best response was stable disease in 10 patients (21%). Disease progression occurred in 32 patients (70%), with a median time to disease progression of 6 weeks. Progression-free survival at 4 and 6 months was 21% and 6%, respectively. Conclusion. The results show that gefitinib monotherapy in advanced SyS refractory to conv

Spectrum of histiocytic neoplasms associated with diverse haematological malignancies bearing the same oncogenic mutation

Histiocytic disorders are a spectrum of rare diseases characterised by the accumulation of macrophage-,

Inactivation of SDH and FH cause loss of 5hmC and increased H3K9me3 in paraganglioma/pheochromocytoma and smooth muscle tumors

Succinate dehydrogenase (SDH) and fumarate hydratase (FH) are tricarboxylic acid (TCA) cycle enzymes and tumor suppressors. Loss-of-function mutations give rise to hereditary paragangliomas/pheochromocytomas and hereditary leiomyomatosis and renal cell carcinoma. Inactivation of SDH and FH results in an abnormal accumulation of their substrates succinate and fumarate, leading to inhibition of numerous a-ketoglutarate dependent dioxygenases, including histone demethylases and the ten-eleven-translocation (TET) family of 5-methylcytosine (5mC) hydroxylases. To evaluate the distribution of DNA and histone methylation, we used immunohistochemistry to analyze the expression of 5mC, 5-hydroxymethylcytosine (5hmC), TET1, H3K4me3, H3K9me3, and H3K27me3 on tissue microarrays containing paragangliomas/pheochromocytomas (n = 134) and hereditary and sporadic smooth muscle tumors (n = 56) in comparison to their normal counterparts. Our results demonstrate distinct loss of 5hmC in tumor cells in SDH- and FH-deficient tumors. Loss of 5hmC in SDH-deficient tumors was associated with nuclear exclusion of TET1, a known regulator of 5hmC levels. Moreover, increased methylation of H3K9me3 occurred predominantly in the chief cell component of SDH mutant tumors, while no changes were seen in H3K4me3 and H3K27me3, data supported by in vitro knockdown of SDH genes. We also show for the first time that FH-deficient smooth muscle tumors exhibit increased H3K9me3 methylation compared to wildtype tumors. Our findings reveal broadly similar patterns of epigenetic deregulation in both