Ollier disease and Maffucci syndrome are non-hereditary skeletal disorders characterized by multiple enchondromas (Ollier disease) combined with spindle cell hemangiomas (Maffucci syndrome). We report somatic heterozygous IDH1 (R132C and R132H) or IDH2 (R172S) mutations in 87% of enchondromas, benign cartilage tumors, and in 70% of spindle cell hemangiomas, benign vascular lesions. In total, 35 of 43 (81%) patients with Ollier disease and 10 of 13 (77%) patients with Maffucci syndrome carried IDH1 (98%) or IDH2 (2%) mutations in their tumors. Fourteen of sixteen patients displayed identical mutations in separate lesions. Immunohistochemistry for mutant R132H IDH1 protein suggested intraneoplastic and somatic mosaicism. IDH1 mutations in cartilage tumors are associated with hypermethylation and downregulation of expression of several genes. Mutations were also found in 40% of solitary central cartilaginous tumors and in four chondrosarcoma cell lines, enabling functional studies to assess the role of IDH1 and IDH2 mutations in tumor formation.

BackgroundMolecular genetic studies on rare tumour entities, such as bone tumours, often require the use of decalcified, formalin-fixed, paraffin-embedded tissue (dFFPE) samples. Regardless of which decalcification procedure is used, this introduces a vast breakdown of DNA that precludes the possibility of further molecular genetic testing. We set out to establish a robust protocol that would overcome these intrinsic hurdles for bone tumour research.FindingsThe goal of our study was to establish a protocol, using a modified DNA isolation procedure and quality controls, to select decalcified samples suitable for array-CGH testing. Archival paraffin blocks were obtained from 9 different pathology departments throughout Europe, using different fixation, embedding and decalcification procedures, in order to preclude a bias for certain lab protocols. Isolated DNA samples were subjected to direct chemical labelling and enzymatic labelling systems and were hybridised on a high resolution oligonucleotide chip containing 44,000 reporter elements.Genomic alterations (gains and losses) were readily detected in most of the samples analysed. For example, both homozygous deletions of 0.6 Mb and high level of amplifications of 0.7 Mb were identified.ConclusionsWe established a robust protocol for molecular genetic testing of dFFPE derived DNA, irrespective of fixation, decalcification or sample type used. This approach may greatly facilitate further genetic testing on rare tumour entities where archival decalcified, formalin fixed samples are the only source.

Because keratin positivity is seen in the majority of cases, pathologists should avoid misinterpretation as metastatic carcinoma. A macronucleolus, three or more mitoses per 10 HPF and fewer than five eosinophilic granulocytes per 10 HPF can be used to further define angiosarcoma of bone.

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On the basis of this experience, we advise caution with the use of hemostatic agents during spinal surgery and - if used - strongly advise the removal of Surgicel® Fibrillar™ after the hemostasis has been achieved to avoid the development of complications due to a mass effect.

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The discovery of an unexpected breast cancer in a 31-year-old transman emphasizes the importance of thorough routine histopathological examination of mastectomy specimens. The number of tissue blocks taken should be based on age and breast weight.

Hemangiopericytoma (HPC) was first described as a neoplasm with distinct morphologic features, presumably composed of pericytes. In soft tissue, it is accepted that most such lesions are solitary fibrous tumors (SFTs), monophasic synovial sarcomas (SSs), or myofibromatoses. It is unclear whether HPC of bone exists. We reviewed 9 primary "HPC" of bone from 4 institutions diagnosed between 1952 and 2002. Immunohistochemistry was performed for CD31, CD34, von Willebrand factor, smooth muscle actin, keratin AE1/AE3, and epithelial membrane antigen. There were 4 male and 5 female patients between 21 and 73 years. All tumors were located within bone, either sited within spine or extremities. All tumors showed thin-walled branching vessels surrounded by undifferentiated spindle or round cells. These cells showed variation in their morphologic pattern: 6 tumors showed a pattern-less architecture and varying cellularity, consistent with SFT; 3 of 5 cases examined were CD34-positive. Three tumors showed more densely packed sheets and fascicles of poorly differentiated cells, resembling SS, of which 2 showed focal staining for keratin AE1/AE3 or epithelial membrane antigen. Fluorescent in-situ hybridization confirmed the presence of SS18 rearrangement in 1 of 2 tumors examined. In conclusion, similar to their soft-tissue counterpart, HPC-like features in bone are a nonspecific growth pattern rather than a true diagnosis. We confirm the existence of 2 entities: SFT and SS of bone. Both are characterized by distinct morphology and immunohistochemical profile. SFT of bone is located within spine and has a better prognosis, whereas SS of bone is located within long bones having a poor prognosis.