Bone Tumoursx

Bone Tumours • Benign o Clinically indolent o Localised, slow growing, self-limiting mass o Can become malignant • Malignant • o Clinically aggressive o Rapid growth destroying surrounding structures, potential for recurrence and spread o Some tumours are borderline benign/malignant; difficult to classify • Primary tumour o Arises from constituent cells of the organ • Metastases • o Spreads via blood stream, lymph vessels, along nerves o Involved a new, distant organ or tissue • For bone and soft tissue tumours o -oma: benign o -sarcoma: malignant Bone Tumour Types • Metastases: o Usually terminal phase o >90% from thyroid, breast, lung, kidney or prostate o Commonly axial skeleton o Typically lytic (kidney, thyroid) vs sclerotic (prostate) metastases • Primary haematopoietic tumours o Blood cancers  From developing blood cells in marrow  Occupy the blood ie. In circulation o No benign examples o Leukaemias, lymphomas, myelomas o Myeloma  Neoplastic plasma cell proliferation • Activated B lymphocytes produces Ig’s  Most common tumour in bone  Osteolytic  Infiltration of various organs  Associated with amyloidosis • Primary bone tumours o Tumours arising from bone, excluding marrow o Mainly in long bones, mostly benign o E.g. osteosarcoma, chondrosarcoma, Ewing sarcoma Sarcomas of Bone • Recognised precursors o Paget’s disease o Radiation exposure o Bone infarction o Chronic osteomyelitis o Genetic syndromes e.g. Ollier disease – enchondromatosis Clinical Features • Pain o Present in both benign and malignant tumours o In sarcomas, high pain severity o Mimics arthritic pain, radiates if impinging on nerve • Swelling o May be the only sign in benign tumours o Extraosseous extension or bone expansion o Changed motility of skin and soft tissue overlying tumour • Limitation of movement o Indicative of tumour location o Adjacent reactive synovitis • Pathological fracture o Break through abnormal bone o Reflection of tumour architecture • Systemic symptoms o Fever, fatigue, malaise, weight loss Radiological Features • Location: giant cell tumour and chondroblastoma involves ends of long bones • Size: classed <6cm or >6cm • Pattern of bone destruction o Transition between tumour and surrounding bone  Sharp with sclerosing rim: slow growth  Ill defined: fast growth o Other features of rapid growth:  Elevated periosteal reaction (Codman triangles)  Involvement of both cortices of long bone before extraosseous extension o Multifocal lesion  metastases, but some benign lesions Histopathological Features • Classified according to tumour cell type and clinical behaviour  Cell type: o Can arise from any constituent cell of an organ o Usually from most prevalent cell type Types • Chondrocytes: chondro• Osteoblasts: osteo• Fibroblasts: fibro-  Osteoclasts: giant cell • Haematopoietic • Embryonal remnant cells (neuroectoderm and notochord) Classification • Chondroid o Cartilage producing tumour o Benign: osteochondroma, chondroma, chondroblastoma o Malignant: chondrosarcoma • Osteogenic o Bone producing tumour o Benign: osteoid osteoma, osteoblastoma o Malignant: osteosarcoma • Fibrogenic o Collagen producing tumour o Benign: fibrous dysplasia o Malignant: fibrosarcoma • Others o Ewing sarcoma o Giant cell tumour of bone o Aneurysmal bone cyst Chondroid Tumours • Osteochondroma o Most common primary bone tumour o Typically in metaphyses of long bones in <30yr olds o Multiple if hereditary o Can recur if incompletely removed o Cartilagecapped projection on periosteum o Marrow cavity continuous with that of underlying bone • Chondroma o Teenagers-young adults o Benign proliferation of chondrocytes, producing cartilage o In bone: enchondroma, most common in hand, foot bone medulla o On bone: periosteal chondroma, most common in long bones, hands, feet o Outside bone: soft tissue chondroma o Multiple: enchondromatosis e.g. Ollier disease, Maffucci syndrome • Chondroblastoma o Uncommon o Epiphysis of immature long bones o Proliferation of immature chondrocytes (chondroblasts), producing cartilage • Chondrosarcoma o Diverse group of cartilage producing malignant tumours o De novo or from pre-existing benign lesion o Common in pelvis, shoulder girdle, and proximal limbs Osteogenic Tumours • Osteoid osteoma and osteoblastoma o Inter-related o More common in males, childhood-early adulthood o Histology identical: haphazard production of bony trabeculae by proliferating osteoblasts o Distinction: predilection for osteoblastomas in spine, if >2cm, then osteoblastoma • Osteosarcoma o Subtypes  Conventional: osteoblastic, chondroblastic, fibroblastic  Secondary: Paget’s, radiation o Most common in long bones of children o Associated with retinoblastoma: RBI gene affected on chr.13q  Bilateral retinoblastomas  White pupils < 3yrs o Also associated with other bone tumours: chondrosarcomas and Ewing sarcomas o Increased haphazard production of fine osteoid with high density of tumour cells compared to osteoblastoma Fibrogenic Tumours • Fibrous dysplasia o Benign fibro-osseous lesion in the medulla o Prognosis generally good o Rarely becomes sarcoma o Common in skull and facial bones • Fibrosarcoma o Malignant fibrogenic tumour o Common in long bone metaphysis o High cell density with sheet of crowded spindle cells Miscellaneous • Ewing sarcoma o Primitive neuroectodermal tumour (PNET)/Askin tumour if in chest o Mainly in children, males more than women o Common in long bones, pelvis, ribs o Genetic abnormality: t(11:22)-chimeric protein o Proliferation of primitive rounded cells replacing bone • Giant cell tumour o Aka osteoclastoma o Benign, can become malignant o Common in skeletally mature patients in long bones • Aneurysmal bone cyst o Benign cystic tumour o Common in <20 year olds, ends of long bones and spine o Blood filled space in-between giant cells, fibroblastic cells and bone