The rare primary bone sarcomas: imaging-pathological correlation

Radiological manifestations of synovial sarcoma

Synovial sarcoma (SS) is a rare malignant neoplasm of the soft tissue adjacent to joints. It is the most commonly diagnosed non-rhabdomyosarcoma soft-tissue sarcoma (STS) in childhood (30%). Its most frequent location is the knee and ankle, and it is the most common STS to affect the foot. Unlike other STS, it has slow growth and an earlier age at diagnosis (adolescents and young adults), which is why many cases are initially misdiagnosed as benign processes. Magnetic resonance imaging (MRI) is key due to its characterisation capabilities as SS shares features with other STS. Definitive diagnosis is achieved through a pathological study that shows the pathognomonic translocation t(x;18)(p11;q11) with the fluorescence in situ hybridisation (FISH) technique. The objective of this article is to highlight the key characteristics that are useful for diagnosing SS, fundamentally through the use of radiological imaging techniques, as well as nuclear medicine and pathological studies, illustrated with cases diagnosed in our centre.

Treatment of Distal Femoral Malignant Mesenchymal Tumor With Extensor Mechanism Transfer: A Case Report and Surgical Technique

Malignant mesenchymal tumors are a diverse group of aggressive cancers originating from mesenchymal cells in connective tissues such as bone, muscle, cartilage, and fat. These tumors often invade surrounding tissues and metastasize to distant organs, posing significant treatment challenges. Among them, malignant mesenchymal tumors located in the distal femur are particularly rare, with limited reports detailing effective surgical and functional reconstruction strategies following wide resection. This case report focuses on the treatment of a distal femoral malignant mesenchymal tumor managed at our clinic, where wide resection was followed by reconstruction using a tumor resection prosthesis and extensor mechanism transfer. The report highlights the innovative surgical technique employed to restore extensor function while maintaining structural integrity, addressing a critical gap in the literature. By sharing insights into this approach, this report aims to contribute to the growing body of knowledge on limb salvage surgery and improve outcomes for patients with similar complex conditions.

The 2020 World Health Organization classification of bone tumors: what radiologists should know

Improved understanding of tumor biology through molecular alteration and genetic advances has resulted in a number of major changes in the 2020 World Health Organization's (WHO) classification of bone tumors. These changes include the reclassification of the existing tumors and the introduction of several new entities. A new chapter on undifferentiated small round cell sarcomas of bone and soft tissue was added to classify Ewing sarcoma and the family of Ewing-like sarcomas, which share similar histologies but different molecular and clinical behaviors. Knowledge of the current classification of bone tumors is essential to ensure the appropriate recognition of the inherent biological potential of individual osseous lesions for optimal treatment, follow-up, and overall outcome. This article reviews the major changes to the 2020 WHO's classification of primary bone tumors and the pertinent imaging of selected tumors to highlight these changes.

Solitary Lymph Node Metastasis From a Malignant Peripheral Nerve Sheath Tumor of the Thoracic Vertebra Revealed on FDG PET/CT

ABSTRACT

Malignant peripheral nerve sheath tumors (MPNSTs) of bone are rare. It is mainly located in the appendicular skeleton. The lung is the most common site of metastasis. Solitary lymph node metastasis is very rare. Herein, we report the imaging findings of MPNST in the first thoracic vertebra with lymph node metastasis in the left axillary region. On FDG PET/CT, these lesions had intense FDG uptake. This case highlights that solitary lytic thoracic vertebral lesion with intense FDG accumulation should regard MPNST as a differential diagnosis and that FDG PET/CT has an important role in the initial staging of MPNST.