Novel RGAG1-BCOR gene fusion revealed in a somatic soft tissue sarcoma with a long follow-up.

BCOR-rearranged sarcomas are rare and belong to the Ewing-like sarcomas (ELS). Their morphology and histopathological features make the diagnosis challenging. We present a case, initially diagnosed as an unusual extraskeletal myxoid chondrosarcoma (EMC). A 54-year-old male patient developed an asymptomatic swelling of the lower leg. Imaging showed a 9.5-cm large intramuscular soft tissue mass. Due to its morphological and immunohistochemical profile on biopsy, it was initially diagnosed as an EMC. The patient was treated by complete resection and adjuvant radiotherapy and remained free of tumor at 7 years follow-up. Using next-generation sequencing (NGS), we retrospectively identified RGAG1-BCOR gene fusion (confirmed by RT-PCR), which has not been described in somatic soft tissue tumors so far. This finding broadens the spectrum of partner genes in the BCOR-rearranged sarcomas in a tumor with a well-documented, long clinical follow-up.

EWSR1-NFATC2 and FUS-NFATC2 Gene Fusion-Associated Mesenchymal Tumors: Clinicopathologic Correlation and Literature Review.

The spectrum of mesenchymal tumors associated with rearrangements of the EWSR1 gene has been growing in recent years due to progress in molecular detection techniques. Originally identified as the gene involved in the pathogenesis of Ewing sarcoma, the EWSR1 gene is now known to be rearranged in diverse clinical and histopathological entities. The NFATC2 gene is one of the many translocation partners of EWSR1 in gene fusions in a morphologically typical, albeit rare, subgroup of mesenchymal tumors. Little is known about the clinical characteristics of tumors containing NFATC2 gene rearrangements since most of the few reports published describe molecular rather than clinical aspects. In the current study, we report three patients with tumors carrying the EWSR1-NFATC2 gene translocation, including one rare primary tumor of soft tissues. Another patient with a benign-appearing bone tumor with a unique FUS-NFATC2 gene translocation is described. In various mesenchymal tumors (e.g., myxoid/round cell liposarcoma, low-grade fibromyxoid sarcoma, or angiomatoid fibrous histiocytoma), the FUS gene, as a member of the TET family, may be alternatively rearranged instead of the EWSR1 gene without any noticeable influence on the microscopical appearance or clinical outcome. This fact seems not to apply to mesenchymal tumors with the involvement of the NFATC2 gene because both in our experience and according to the extensive literature review, they have different properties on the morphological and molecular level. Both ESWSR1-NFATC2 and FUS-NFATC2 fusion-carrying tumors do not show microscopical or clinical features of Ewing sarcoma.

Rotationplasty in the elderly.

Purpose. Rotationplasty has proven its efficacy in the treatment of malignant bone tumors of the lower extremity in predominantly young patients. To our knowledge this procedure has not been reported in patients over 60 years before. Materials and Methods. 3 patients over 60 years with an A1-rotationplasty because of a sarcoma were included in this study. Complications and functional results were recorded. In one patient an electromyography was done. Results. Despite electromyography showing good adaptation of the muscles to the altered function, the functional results of these three patients were limited. two out of three patients needed a cane for walking distances over 200 meters. No secondary amputation was necessary. Discussion. Our study demonstrates that rotationplasty is an alternative to an above-knee amputation in older patients but with poorer functional results in comparison to younger patients. However, limb-salvage surgery should be preferred whenever possible.

A model for clubfoot based on micro-CT data.

The pathological anatomy of idiopathic clubfoot has been investigated for more than 180 years using anatomy, computed tomography (CT), histology and microscopy. Seven idiopathic clubfeet and two normal feet of aborted fetuses were dissected in the present study, with special emphasis on the shape of the cartilage and bones. A three-dimensional (3D) micro-CT system, which generates a series of X-ray attenuation measurements, was used to produce computed reconstructed 3D data sets of each of the separated bones. Based on the micro-CT data scans a high-definition 3D colour printing system was used to make a four times enlarged clubfoot model, precisely presenting all the bony malformations. This model reflects the complexity of the anatomy of this disease and is designed to be used in the workshops of orthopaedic surgeons and physiotherapists, for training in new surgical and manipulation techniques.

Anatomical study for an updated comprehension of clubfoot. Part II: Ligaments, tendons and muscles.

PURPOSE: The aim of our study was to evaluate the pathological anatomy of the ligaments, tendons and muscles in clubfeet, and to show whether the dysbalance of shortened and elongated structures is an adaptive process or a primary factor inducing the misshaped bones and cartilagines. METHODS: Surgical exposure was performed on seven idiopathic clubfeet specimens, aborted between the 25th and 37th week of gestation and compared to two normal feet (27th and 36th week of gestation). RESULTS: The medial stabilisation system of the foot was found shortened, but all ligaments could be dissected. On the lateral side, the calcaneofibular ligament in particular was both 'shortened' and 'elongated', depending on the course of the fibres to the axis of motion in the subtalar and talocalcaneonavicular joint. The main difference to the normal feet was found in the thickened tendon of the tibialis posterior forming a bulbus before dividing into fascicules. CONCLUSIONS: We presume the ossification disturbance of the calcaneus to be the primary fault. This disturbance will influence the reduction of the varus position, so ligaments and tendons will be conformed to the misshaped bones.

Anatomical study for an update comprehension of clubfoot. Part I: Bones and joints.

PURPOSE: The aim of our study was to elucidate the gross anatomical changes of bones and joints in idiopathic clubfeet. METHODS: Gross dissection was carried out on seven idiopathic clubfeet of fetuses aborted between the 25th and 37th week of gestation and compared to two normal feet (27th and 36th week of gestation). Particular attention was paid to the articular surfaces, shapes and angles of all bones and their skeletal relationships. RESULTS: The talar neck-trochlea angle in clubfeet ranged from 37 degrees to 41 degrees , in normal feet from 27 degrees to 33 degrees . In clubfeet the deviation of the neck of the talus relative to the body was between 28 degrees and 43 degrees , in normal feet between 22 degrees and 24 degrees . The posterior joint surface was in an anterolateral position and even flat transversely. The head of the clubfeet tali was turned along a longitudinal axis in the opposite direction compared to the normal ones. Instead of a typically saddle-shaped posterior talar surface of the calcaneus, it was triangular and flat transversely, and a bony stability in the subtalar joint was not achieved. The angle of torsion of the calcaneus showed no significant difference between normal and clubfeet. The anterior surface was flat, medially twisted and orientated upwards. CONCLUSIONS: We presume that the calcaneus is the primary fault, which might be explained by pathologic biomechanical forces during development.