Recurrent and novel fusions detected by targeted RNA sequencing as part of the diagnostic workflow of soft tissue and bone tumours.

The identification of gene fusions has become an integral part of soft tissue and bone tumour diagnosis. We investigated the added value of targeted RNA-based sequencing (targeted RNA-seq, Archer FusionPlex) to our current molecular diagnostic workflow of these tumours, which is based on fluorescence in situ hybridisation (FISH) for the detection of gene fusions using 25 probes. In a series of 131 diagnostic samples targeted RNA-seq identified a gene fusion, BCOR internal tandem duplication or ALK deletion in 47 cases (35.9%). For 74 cases, encompassing 137 FISH analyses, concordance between FISH and targeted RNA-seq was evaluated. A positive or negative FISH result was confirmed by targeted RNA-seq in 27 out of 49 (55.1%) and 81 out of 88 (92.0%) analyses, respectively. While negative concordance was high, targeted RNA-seq identified a canonical gene fusion in seven cases despite a negative FISH result. The 22 discordant FISH-positive analyses showed a lower percentage of rearrangement-positive nuclei (range 15-41%) compared to the concordant FISH-positive analyses (>41% of nuclei in 88.9% of cases). Six FISH analyses (in four cases) were finally considered false positive based on histological and targeted RNA-seq findings. For the EWSR1 FISH probe, we observed a gene-dependent disparity (p = 0.0020), with 8 out of 35 cases showing a discordance between FISH and targeted RNA-seq (22.9%). This study demonstrates an added value of targeted RNA-seq to our current diagnostic workflow of soft tissue and bone tumours in 19 out of 131 cases (14.5%), which we categorised as altered diagnosis (3 cases), added precision (6 cases), or augmented spectrum (10 cases). In the latter subgroup, four novel fusion transcripts were found for which the clinical relevance remains unclear: NAB2::NCOA2, YAP1::NUTM2B, HSPA8::BRAF, and PDE2A::PLAG1. Overall, targeted RNA-seq has proven extremely valuable in the diagnostic workflow of soft tissue and bone tumours.

Optical Genome Mapping for Comprehensive Cytogenetic Analysis of Soft-Tissue and Bone Tumors for Diagnostic Purposes.

Soft-tissue and bone tumors represent a heterogeneous group of tumors encompassing more than 100 histologic subtypes today. Identifying genetic aberrations increasingly is important in these tumors for accurate diagnosis. Although gene mutations typically are detected by second-generation sequencing, the identification of structural variants (SVs) and copy number alterations (CNAs) remains challenging and requires various cytogenetic techniques including karyotyping, fluorescence in situ hybridization, and arrays, each with important limitations. Optical Genome Mapping (OGM), a non-sequencing-based technique for high-resolution detection of SVs and CNAs, was applied in a retrospective series of diagnostic soft-tissue and bone tumor samples. Sample preparation was successful in 38 of 53 cases, with the highest success rate in nonadipocytic soft-tissue tumors (24 of 27 cases; 89%). In 32 of 35 cases carrying a diagnostic SV or CNA, OGM identified the aberration (91%), including a POU2AF3::EWSR1 fusion in a round cell sarcoma and a translocation t(1;5)(p22;p15) in a myxoinflammatory fibroblastic sarcoma. Interestingly, OGM shed light on the genomic complexity underlying the various aberrations. In five samples, OGM showed that chains of rearrangements generated the diagnostic fusion, three of which involved chromoplexy. In addition, in nine samples, chromothripsis was causal to the formation of giant marker/ring/double-minute chromosomes. Finally, compared with standard-of-care cytogenetics, OGM revealed additional aberrations, requiring further investigation of their potential clinical relevance.

An egg in the leg: Case report of an osteochondrolipoma.

Osteochondrolipomas, a very rare combination of chondroid and osseous differentiation within lipomas, are typically found in the neck and head area. We present the case of an osteochondrolipoma in the thigh of a 54-year-old female, with matching histological and cytological correlation. To the best of our knowledge, this atypical location has only been reported once in the literature.

Management of Synovial Sarcoma in a Tertiary Referral Center: A Retrospective Analysis of 134 Patients.

BACKGROUND: Synovial sarcomas (SS) are malignant mesenchymal neoplasms that account for about 10% of all sarcomas. Complete surgical excision is the mainstay of primary treatment for localized disease, but SS have a high tendency for local relapse and metastases. Metastatic disease is commonly treated with systemic chemotherapy. METHODS: We designed a retrospective analysis to describe the clinical presentation, course of treatment, outcome, and prognosis of patients with SS. Univariate and multivariate analyses were performed for potential prognostic factors. RESULTS: We identified 134 patients treated between 1987 and 2018, with a cutoff date of December 2018. Demographics, disease characteristics, treatment, and survival rates were collected and analyzed. The median overall survival (mOS) from the date of diagnosis was 96.7 months. The median progression-free survival was 6.37 months. Disease-free survival was 26 months. Age over 65 years was found to be a prognostic factor with statistically significant value in the univariate analysis regarding mOS (p = 0.015) and mOS after local relapse (p = 0.0228). CONCLUSIONS: Even though our study is limited by the retrospective nature of the analysis, it adds an important amount of clinical data regarding the treatment and outcome of SS.

Intraosseous schwannoma of the glenoid: case report and literature review.

Intraosseous schwannomas represent an extremely rare subgroup of schwannomas, accounting for <1% of all primary bone tumors. They mostly occur in the mandible, the maxilla, the sacrum, and they are also seen in long bones. We herein report a rare presentation of an intraosseous schwannoma in the glenoid of a 49-year-old patient. She complained of shoulder pain and was referred to the orthopaedic oncologist after detection of a suspicious lesion on imaging. Biopsy revealed benign spindle cells and immunohistochemistry was positive for S100. Because of the rarity of these intraosseous schwannomas it is important to recognize their radiological and histological features and make a differential diagnosis with other lytic tumors. Only if these characteristics are recognized, correct treatment can be given with definite curettage and bone grafting and correct follow-up with avoidance of unnecessary adjuvant therapy.

Tenosynovial giant cell tumor of the pes anserinus bursa with secondary involvement of a reconstructed autologous anterior cruciate ligament - A case report.

Tenosynovial giant cell tumor (TGCT) is defined by the World Health Organization (WHO) as a family of lesions most often arising from the synovium of joints, bursae and tendon sheaths. It is composed of synovial- like mononuclear cells, admixed with multinucleate giant cells, foam cells, siderophages and inflammatory cells (1). It can have various clinical manifestations, and is therefore subdivided in a diffuse and a localized/ nodular subtype. Furthermore, the lesions can have an intra- or extra-articular location. The purpose of this paper is to present the case of a 41-year-old male suffering from multifocal extra- and intra-articular TGCT of the right knee, with involvement of the pes anserinus bursa and an anterior cruciate ligament (ACL) autograft respectively. The ACL reconstruction was performed 11 years prior to the diagnosis of the TGCT, using tendons harvested from the pes anserinus. Our case illustrates the risk of transferring TGCT from an extra- to intra-articular location during ACL reconstruction, when using tendons of a pes anserinus prone to develop this condition. To our knowledge, no similar case was published in the literature so far.

Establishment and Characterization of Histologically and Molecularly Stable Soft-tissue Sarcoma Xenograft Models for Biological Studies and Preclinical Drug Testing.

Soft-tissue sarcomas (STS) represent a heterogeneous group of rare, malignant tumors of mesenchymal origin. Reliable in vivo sarcoma research models are scarce. We aimed to establish and characterize histologically and molecularly stable patient-derived xenograft (PDX) models from a broad variety of STS subtypes. A total of 188 fresh tumor samples from consenting patients with localized or advanced STS were transplanted subcutaneously in NMRI-nu/nu-immunodeficient mice. Once tumor growth was observed, the material was passaged to a next generation of mice. A patient-derived tumor sample was considered "successfully engrafted" whenever the sample was transplanted to passage 1. A PDX model was considered "established" when observing stable morphologic and molecular features for at least two passages. With every passage, histologic and molecular analyses were performed. Specific genomic alterations and copy-number profile were assessed by FISH and low coverage whole-genome sequencing. The tumor engraftment rate was 32% (61/188) and 188 patient samples generated a total of 32 PDX models, including seven models of myxofibrosarcoma, five dedifferentiated liposarcoma, five leiomyosarcoma, three undifferentiated pleomorphic sarcoma, two malignant peripheral nerve sheet tumor models, and single models of synovial sarcoma and some other (ultra)rare subtypes. Seventeen additional models are in early stages of engraftment (passage 1-2). Histopathologic and molecular features were compared with the original donor tumor and were stable throughout passaging. The platform is used for studies on sarcoma biology and suited for in vivo preclinical drug testing as illustrated by a number of completed and ongoing laboratory studies.

Successful forearm prosthesis fitting in a patient with epidermolysis bullosa dystrophica: Case report.

BACKGROUND: Epidermolysis bullosa dystrophica is a rare dermatological disease characterized by extreme skin fragility and elevated risk of developing a squamous cell carcinoma. In some cases, amputation of a limb is necessary. Case description and methods: A 37-year-old man with recessive, severe generalized epidermolysis bullosa dystrophica developed a squamous cell carcinoma on the right forearm requiring a below-elbow amputation. Preoperative advice concerning indication and level of amputation was given. Due to potential skin problems, a conventional prosthesis was not feasible. Findings and outcomes: A custom-designed adaptive prosthesis with an upper arm cuff was trialed and was well tolerated. Multiple working tools, attached with a rotation and inclination system, allowed independence and return to work. CONCLUSION: Despite multiple potential skin problems of the stump, the patient was successfully fitted with a custom-designed adaptive prosthesis. Preparation for this fitting was done by a comprehensive multidisciplinary patient-centered approach. Clinical relevance Despite severe skin fragility, a patient with epidermolysis bullosa dystrophica was successfully fitted with a custom-designed adaptive upper limb prosthesis allowing good functional outcome. This required a multidisciplinary and patient-centered approach.

The role of the MTHFR C677T polymorphism in methotrexate-induced toxicity in pediatric osteosarcoma patients.

AIM: Osteosarcoma patients receive high doses of methotrexate (MTX). However, pharmacogenetic information remains limited and has mainly been investigated in leukemia so far. PATIENTS & METHODS: We investigated the link between the MTHFR C677T genotype, toxicity levels (mucositis, MTX plasma level, hematological toxicity and hepatotoxicity) and survival of 48 pediatric osteosarcoma patients. RESULTS: The TT genotype did not show more toxicity compared with the CC/CT genotype. However, plasma MTX levels were related with mucositis, but not with hematological toxicity, nor hepatotoxicity. Survival rates did not differ between homozygous and non-homozygous patients. Yet, homozygous patients had higher relapse risk. CONCLUSION: The MTHFR C667T polymorphism is not predictive for toxicity or overall survival, but could be used for relapse risk stratification.

Single-Centre Experience of Systemic Treatment with Vincristine, Ifosfamide, and Doxorubicin Alternating with Etoposide, Ifosfamide, and Cisplatin in Adult Patients with Ewing Sarcoma.

The treatment of Ewing sarcoma (ES) in adult patients requires a multidisciplinary approach. Systemic therapy remains an important component of clinical management of this disease. ES is extremely rare in adult patients. Due to the rarity of the disease, no standard of care in terms of chemotherapy for the adult population exists, and the level of evidence for individual agents or some multidrug combinations is limited. Most regimens that are used in both adults and children include anthracyclines, etoposide, vincristine, cyclophosphamide, and ifosfamide. In this report, we describe our experience with the alternating use of triple combination therapies based on vincristine, ifosfamide, and doxorubicin (VIA) and an etoposide, ifosfamide, and cisplatin combination (VIP). We retrospectively evaluated the response rates, outcome, and tolerance of adult patients (n = 64) treated with VIA/VIP between 1990 and 2014. The patients included were treated with perioperative chemotherapy (53.1% neoadjuvant therapy and 17.2% adjuvant therapy) or had synchronous metastases at diagnosis (29.7%). Five-year overall survival rate was 52.2% for all patients, 72.2% for patients with localized disease, and 5.3% in patients with synchronous metastases. Overall response rate (ORR) was 37% after 2 cycles of VIA and 2 cycles of VIP. There were no patients with progressive disease (PD).

Perineural spread of endometriosis along the obturator nerve into the adductor thigh compartment.

We report the case of a young woman with recurrent unilateral hip pain. A polylobular cystic mass was found in the right adductor space. Magnetic resonance imaging (MRI) revealed a polynodular mass migrating from the intrapelvic region along the obturator nerve. Because of a history of cyclic pain and the characteristics on MRI (hypointense rim and spots of spontaneous hyperintense signal on T1-weighted images), an endometrioma was suspected. The diagnosis of endometriosis was later confirmed through ultrasound-guided biopsy.

Clinical outcome of surgical intervention for recalcitrant infero-medial heel pain.

A retrospective review was conducted in 28 patients (31 feet) with recalcitrant infero-medial heel pain, to assess the clinical outcome of a combined release of the first branch of the lateral plantar nerve and the plantar fascia. All patients were questioned by telephone interview on their pre- versus post-operative level of pain and function (based on the Kitaoka mid-foot scale and the visual analog scale), and their satisfaction with the result of the intervention. Limitations of functional activity decreased, maximum walking distance increased and the level of pain decreased from 8.9 to 1.4 on the visual analog scale. The majority of patients was satisfied with the surgery (90.3%) and would undergo the same procedure again or would recommend it (92.9%). While conservative management remains the gold standard for treatment of infero-medial heel pain and/or plantar fasciitis, patients with recalcitrant disease usually can be effectively treated surgically with a combined release of the plantar fascia and the first branch of the lateral plantar nerve.