Bone And Soft Tissue Tumours

BONE AND SOFT TISSUE TUMOURS    

  Metastatic Tumours The most common bony malignancies are metastatic carcinomas. With improved treatment regimens, which has prolonged survival, the deletion is involved in over half of all metastatic carcinomas through hematogenous spread. Spread can be arterial or venous (retrograde venous spread is through the veins of Batson in the spine). Metastatic lesions represent the most common cause of pathology fractures due to a neoplasm. Usually are multiple, but can be solitary. Most common primaries are breast, prostate, lung, kidney and thyroid, in that order. Renal mets are quite vascular and have cold bone scans, and histology may demonstrate clear cells that are PAS positive. Prostate and breast mets are typically osteoplastic. Wilms’s tumour and neuroblastoma (rosettes) are the most common metastatic lesions in childhood. Prophylactic fixation of weight-bearing bones (often with PMMA supplementation) is recommended for lesions >2.5 cm in diameter or involving >50% of the cortex, or in patients having pain. XRT is often helpful for tumours metastatic to bone (it is administered preop in patients with thyroid and kidney mets). Work-up should include labs (increased calcium common but nonspecific), bone scan (looking for multiple lesions), CT (axial lesions, and chest CT), angiography (preop for thyroid and hypernephroma mets), and biopsy. In general, 50% of patients with bony mets will survive 6 months and 30% will survive 1 year. Shorter survival periods can be anticipated with lung cancer, and longer periods with thyroid mets.

 

Cortical osteoid osteoma Calcar femur with florid cortical reaction

Primary Bone Tumours Oesteogenic Lesions Osteoid Osteoma - Usually are intracortical lesions of any bone, especially the femur, tibia, and vertebra (posterior elements), with a characteristic nidus and associated pain. The classic pain is worse at night, relieved by salicylates (not narcotics), and exacerbated by alcohol. Bone scans, tomograms, and CT are often helpful, Cortical osteoid osteoma Calcar femur with florid cortical reaction

spontaneous resolution. Treatment ordinarily consists of surgical removal of the nidus with a marginal excision. Osteoblastoma - Characterised by immature osteoid production and found commonly in the cancellous bone of the spine (posterior elements) and skull. Osteoma Paget’s Disease This disease, which affects about 3% of men and women, is characterised by increased bony turnover common in Australia and N.Z. Increased osteoplastic bone resorption with irregular bone formation leads to focally deficient bone. Paget’s disease typically involves the sacrum, spine, femur and cranium of older patients. Some have hypothesised a viral etiology. Features of Paget’s include deformities (bowing), pain, change in size of bones (increased hat size), kyphosis, and systemic features like cranial nerve impingement, bruits, and high-output cardiac failure. Lab studies are notable

for increased alkaline phosphatase (osteoblasts) and urinary hydroxyproline (osteoclasts). Radiographic features vary with the stage of the disease but include cortical thickening, coarse trabeculae, sclerotic ivory or enlarged picture frame vertebrae, cotton wool appearance of the femur and pelvis, and osteoporosis circumscripta of the calvarium. Late radiographic hallmarks include enlarged bone, thickened cortices, and prominent trabeculae. Bone scans are also helpful for screening. Histologically there is mosaic. Fractures occur commonly, are usually transverse, and frequently require internal fixation; total hip arthroplasty is often required for stabilisation of proximal femur fractures. Available treatment for symptomatic patients (with significant deformity or impending fracture) includes calcitonin (directly inhibits osteoplastic bone resorption); Malignant degeneration (usually to osteosarcoma, chondrosarcoma, or MFH) has been reported in up to 6% of cases and is usually heralded with an increase in pain. Malignant degeneration of Paget’s disease usually carries a poor prognosis. (See case13 ). Click to see pot from Case 13 Ossifying Fibroma (Osteofibrous Dysplasia, Campanacci’s Tumour) - A variant of fibrous dysplasia. Osteosarcoma The most common primary bone malignancy in children (boys > girls), occurs most commonly in the second and third decades of life. It is characterised by the production of osteoid directly from malignant spindle cell stroma. The knee and proximal humerus are common sites, and early diagnosis is difficult. A relatively painless mass is a frequent presentation. Osteosarcomas are classified as primary or secondary (following a preexisting lesion such as Paget’s or a result of XRT, and usually seen in older patients). Primary

tumours are further classified as central or juxtacortical. (See case 6 ). Click to see pot from Case 6 Central Osteosarcomas Juxtacortical Osteosarcomas Periosteal Osteosarcoma High-Grade Surface Osteosarcoma

Chondrogenic Lesions Chondromas - Benign tumours of mature hyaline cartilage usually located within bone (enchondroma), but occasionally on the bony surface (periosteal chondroma). Enchondroma - Benign cartilaginous neoplasm arising in diaphyseal medullary cavities of long bones, possibly from epiphyseal plate remnants. Can be solitary or multiple (Ollier’s disease [alone] and Maffucci’s syndrome [with skin hemangiomata]both with higher rates of malignant transformation [up to 30% in Ollier’s]). Enchondromas are asymptomatic and can be located in any bone, especially in the hands and feet. Periosteal Chondroma Osteochondroma (Osteocartilaginous Exostosis) One of the most common benign bone tumours. These lesions represent a disorder of normal enchondral bone growth, and are usually sessile or pedunculated lesions arising from the cortex of a long bone adjacent to the epiphyseal plate. Tumour enlargement is common and ceases after maturity. Malignant transformation (to low-grade chondrosarcoma) is possible, and is more common with multiple osteochondromas and more proximal lesions and growth with skeletal maturity. Multiple hereditary exostosis (Ehrenfried’s disease) is an autosomal dominant disorder with a mild decrease

in stature, normal intelligence, and multiple osteochondromas. It is commonly accompanied by leg length discrepancy, knee and elbow angular deformities, and other skeletal abnormalities. Osteochondromas develop in multiple metaphyses of affected children and they continue to increase in size and number until skeletalmaturity. Problems include nerve compression (especially peroneal nerve), ankle diastasis, angular deformities, and malignant transformation (2%). (See POT). Chondromyxoid Fibroma Chondroblastoma Chondrosarcoma - Second to osteosarcoma in prevalence of bony sarcoma’s. Chondrosarcomas can arise from preexisting lesions (osteochondromas, chondromas) or they can be primary. They are usually associated with dull, deep pain. Radiographs may show invasiveness and soft tissue extension. Chondrosarcomas are commonly divided into five types. (See case 9 ). Click to see pot from Case 9 Central Chondrosarcoma Peripheral or Periosteal Chondrosarcoma Mesenchymal Chondrosarcoma Dedifferentiated Chondrosarcoma Clear Cell Chondrosarcoma Fibrogenic Lesions Simple (Unicameral) Bone Cyst - Benign lesions that occur during growth. Aneurysmal Bone Cyst (ABC).

Fibrous Dysplasia The shepherd’s crook. Fibrous dysplasia is also common the in skull, ribs, and tibia. Radiographs also show a typical ground glass appearance and scalloping from within. Cafe-au-lait spots Albright’s syndrome precocious puberty. Nonossifying Fibroma (Fibrous Cortical Defect) Malignant Fibrous Histiocytoma (MFH). Fibrosarcoma Haematopoietic Lesions Eosinophilic granuloma is a solitary lesion that arises from the reticuloendothelial system in young children. Vertebra plana. Myeloma - Uncontrolled proliferation of marrow plasma cells (highly differentiated B lymphocytes) leads to the development of this tumour, the most common primary malignant tumour in bone. Common presentations include bone pain, anaemia and raised ESR in a 50-60 year old patient. Histology demonstrates sheets of plasma cells (clock faced eccentric nuclei, perinuclear clear area, and increased RER on electron microscopy). Of note, the lesion lacks any background stroma. Xray shows punched out lesions. Treatment is chemotherapy, radiotherapy and surgical stabilisation impending fractures. Lymphoma of Bone (Histiocytic Lymphoma).

Vascular Lesions Undetermined Etiology Giant Cell Tumour - Aggressive, locally recurrent tumour with a low metastatic potential. Represents

about 20% of primary bone tumours. Most lesions occur in closed epiphyses around the knee joint and distal radius of 20 - 40 year old female > male patients (See case 8 ). Click to see pot from Case 8 Ewing’s Sarcoma - Second (to osteosarcoma) most common malignant bone tumour of childhood. Occurs in young (white >> black) children in the flat and axial bones (pelvis), and in the diaphyses of long bones (fibula, femur). Often associated with systemic signs (fever, weight loss) and local tenderness with erythema and induration, and can be confused with osteomyelitis. CLUES TO DIAGNOSIS

CATION/SITE

TYPICAL PATHOLOGY Chondroblastoma,

Epiphyseal

chondrosarcoma, giant cell tumour, infection

Metaphyseal

Any lesion Osteoblastoma, Ewing’s

Diaphyseal

eosinophilic granuloma, lymphoma, adamantinoma, fibrous dysplasia Mets, myeloma, Ewing’s,

Pelvis

chondrosarcoma, Paget’s Disease.

Proximal humerus   

Knee

Chondroid lesions. Osteosarcoma, adamantinoma,   chondromyxoid fibroma Mets, myeloma, Ewing’s

Ribs

chondrosarcoma, fibrous dysplasia

Spine (Vertebral body)

Mets, myeloma, eosinophilic granuloma, chondroma, Paget’s, haemangioma

Spine (Posterior

Aneurysmal bone cyst, osteoid

elements)

osteoma, osteoblastoma

Periosteal

Myosotis, osteosarcoma, chondrosarcoma, chondroma Mets, myeloma, haemangioma,

Multiple lesions

fibrous dysplasia, osteochondromas, enchondromas, histiocytosis X

   Tumours of Muscular Tissue Leiomyoma

Rhabdomyoma Leiomyoscarcoma Rhabdomyosarcoma Tumours of Synovial Tissues Ganglia - Cystic outpouching of a synovium-lined cavity, frequently about the wrist, and consisting of myxoid degeneration of synovial fluid. Histologically, the cyst wall is made up of dense paucicellular collagenous tissue. (See POT). Pigmented Villonodular Synovitis. Treatment Bone Tumours in General Work-up - History (pain - dull/constant/nocturnal; fracture).

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Examine bone / spine / thyroid / breast / abdomen / prostate).

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Blood tests (FBC, ESR, Blood smear, ca/p levels, urine analysis, liver function tests.

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X-rays spine and limbs, bone scan for metastases, CXR, MRI for occult lesions, possibly CT and arteriography.

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Stage (biopsy) lesion. Important principles involved.

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Surgery either amputation or limb salvage.

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Adjuvant chemotherapy (especially for micrometastases) and radiotherapy (local control).