Sarcoma — Rare Cancers of Bone and Soft Tissue

Sarcomas are malignant tumours arising from transformed cells of mesenchymal origin, which form the structural framework of the human body. They are broadly classified into two primary categories: bone sarcomas (such as osteosarcoma, chondrosarcoma, and Ewing sarcoma) and soft tissue sarcomas (including liposarcoma, leiomyosarcoma, and undifferentiated pleomorphic sarcoma). Although they account for approximately one per cent of all adult malignancies, they represent a notably higher proportion of childhood and adolescent cancers.

Pathologically, sarcomas comprise more than seventy distinct histological subtypes, each exhibiting unique biological behaviours, clinical presentations, and sensitivities to therapeutic interventions. Because these tumours can develop virtually anywhere in the body—from the extremities and retroperitoneum to the head and neck—definitive characterisation demands precise histological assessment, immunohistochemistry, and molecular profiling to guide clinical interventions.

Due to their rarity and diversity, sarcomas are frequently misdiagnosed initially as benign cysts, haematomas, or sports-related injuries, leading to potential delays in therapeutic management. Timely identification and referral to a dedicated sarcoma multidisciplinary centre are critical factors in achieving optimal clinical outcomes. Care at a specialised institution ensures accurate histological typing through advanced molecular diagnostics, access to limb-sparing surgical expertise, and tailored systemic therapies. Understanding the specific sarcoma subtype empowers patients to navigate complex choices regarding surgical margins, radiation timing, and clinical trial participation. Furthermore, receiving care aligned with international sarcoma guidelines substantially reduces recurrence risks and enhances long-term quality of life.

Diagnosis demands core needle biopsy guided by ultrasound or CT, evaluated by an experienced sarcoma pathologist. Cross-sectional imaging via MRI provides detailed local anatomical delineation, whereas CT or PET-CT identifies potential pulmonary or distant metastases. Molecular diagnostics play a crucial diagnostic role; tests include fluorescence in situ hybridisation (FISH) or next-generation sequencing (NGS) to identify characteristic gene fusions, such as EWSR1 fusions in Ewing sarcoma, SS18-SSX in synovial sarcoma, or KIT/PDGFRA mutations in GIST.

Sarcomas are categorised into soft tissue sarcomas and primary bone tumours. Major soft tissue subtypes include gastrointestinal stromal tumours (GIST), leiomyosarcoma, liposarcoma, synovial sarcoma, rhabdomyosarcoma, and angiosarcoma. Primary bone sarcomas predominantly comprise osteosarcoma, Ewing sarcoma, and chondrosarcoma. While sarcomas can occur in almost any anatomical site, they most frequently manifest in the arms, legs, trunk, abdominal cavity, and retroperitoneum across both paediatric and adult cohorts.

Management routinely involves complete surgical resection with clear margins, frequently performed by specialist orthopaedic or surgical oncologists aiming to preserve limb function. Preoperative or postoperative radiotherapy is often employed to minimise local recurrence in high-grade tumours. Systemic chemotherapy is standard for chemotherapy-sensitive subtypes such as Ewing sarcoma and osteosarcoma. Targeted therapies are pivotal in certain subtypes, such as tyrosine kinase inhibitors (e.g., imatinib) for gastrointestinal stromal tumours.