Bone tumors Notes

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Bone tumors

NOTES NOTES BONE TUMORS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Abnormal neoplastic bone tissue growth ▪ Benign tumors more common than malignant TYPES ▪ Primary tumors: originate from bone (more common) ▪ Secondary tumors: originate from other organs CAUSES ▪ Unknown RISK FACTORS ▪ Retinoblastoma, Li–Fraumeni syndrome, chronic inflammation, chronic osteomyelitis, Paget’s disease, bone infarcts, radiation SIGNS & SYMPTOMS ▪ Usual appearance: long bones (e.g. femur/ tibia), pelvis, vertebra, etc. ▪ Benign tumors usually asymptomatic, undetected (early stages), discovered by accident ▪ Pain, swelling, erythema ▪ Palpable mass, structural malformation ▪ Pathological fracture, restricted motion range DIAGNOSIS DIAGNOSTIC IMAGING X-ray ▪ Benign tumors tend to have more defined edges (circular/oval) CT scan/MRI ▪ Asses relation with other structures Nuclear medicine ▪ Assess skeletal involvement extent, distribution OTHER DIAGNOSTICS ▪ Biopsy ▫ Histological features TREATMENT MEDICATIONS ▪ Chemotherapy SURGERY ▪ Surgery OTHER INTERVENTIONS ▪ Radiation therapy OSMOSIS.ORG 607
EWING'S SARCOMA osms.it/ewings-sarcoma PATHOLOGY & CAUSES SIGNS & SYMPTOMS ▪ Rare malignant tumor; bone, soft tissue around bone ▪ Small, round blue-stained cells; believed to have neuroectodermal origin ▪ Pelvis, femur, clavicle, humerus, ribs, spine commonly affected ▪ Intense pain (stronger at night); exacerbated by exercise ▪ Soft palpable mass attached to bone; can compress nerves → function loss (e.g. urinary incontinence if sacrum involved) ▪ Swelling, erythema ▪ Systemic symptoms: fever, weight loss can indicate metastases ▫ Lung metastases: most significant cause of death CAUSES ▪ Translocation fuses two regions together ▫ Ewing sarcoma gene (EWS): chromosome 22 ▫ Friend leukemia insertion (FLI1): chromosome 11 ▫ Newly-formed EWS-FLI1 protein: abnormal transcription factor → induce cell division, malignant transformation RISK FACTORS ▪ Usually sporadic; occurs in children, young adults ▪ ↑ risk, Ewing’s sarcoma family history DIAGNOSIS DIAGNOSTIC IMAGING X-ray/CT scan ▪ Permeative process ▫ Bone appears “moth-eaten” ▪ Periosteal reaction ▫ Rapid tumor growth raises periosteum → laminated “onion skin”-like appearance ▪ Sclerosis MRI ▪ Precise tumor location, size, adjacentstructure relation Positron emission tomography (PET) scan ▪ Metastases search Figure 108.1 A histological section of a classic Ewing’s sarcoma. The tumor cells are undifferentiated, closely packed and have vague cytoplasmic borders. There are two distinct populations of light and dark cells. 608 OSMOSIS.ORG OTHER DIAGNOSTICS ▪ Tumor biopsy ▫ Small, round, blue cells
Chapter 108 Bone Tumors TREATMENT MEDICATIONS ▪ Chemotherapy SURGERY ▪ Tumor removal/limb amputation OTHER INTERVENTIONS ▪ Radiation therapy Figure 108.2 An anterior-posterior X-ray of the left shoulder demonstrating a Ewing’s sarcoma of the humeral head. Figure 108.3 A PET-CT scan in the coronal plane demonstrating a Ewing’s sarcoma of the left proximal femur. The tumor, visible on CT scan corresponds well with the high levels of tracer uptake on the PET scan. OSMOSIS.ORG 609
GIANT-CELL TUMOR OF BONE osms.it/giant-cell_tumor_of_bone PATHOLOGY & CAUSES ▪ Benign tumor ▫ Destructive growth, metastases potential ▪ Tumor mass comprises ▫ Tumor cells: giant multinucleated cells from osteoblastic origin ▫ Non-tumor cells: osteoclasts, their precursors ▪ Tumor cells express RANKL → binds to RANK on osteoclasts, precursors membrane → induce cell division, malignant transformation ▪ ↑ osteoclast number (tumor sometimes called osteoclastoma) + absence of control → bone destruction SIGNS & SYMPTOMS ▪ Commonly around knee (distal femur/ proximal tibia) ▪ Pain, swelling ▪ Restricted range of motion ▪ Pathological fractures Figure 108.4 A anterior-posterior radiograph of the wrist demonstrating a giant cell tumor of bone at the subarticular portion of the radius. It has a characteristic soap bubble appearance. DIAGNOSIS DIAGNOSTIC IMAGING X-ray/CT scan ▪ Lucent mass; cortical thinning/destruction; pathological fracture; mineralization, sclerosis absence Figure 108.5 The histological appearance of a giant cell tumor of bone. There are numerous multinucleated osteoclastic giant cells surrounded by smaller mononuclear cells. 610 OSMOSIS.ORG MRI ▪ Homogeneous intensity, well-defined edges Nuclear medicine ▪ “Doughnut” sign ▫ ↑ periphery uptake, ↓ center uptake
Chapter 108 Bone Tumors TREATMENT SURGERY ▪ Resection OTHER INTERVENTIONS ▪ Radiation therapy Figure 108.6 The gross pathological appearance of a giant cell tumor of bone affecting the distal femur. OSTEOBLASTOMA osms.it/osteoblastoma PATHOLOGY & CAUSES ▪ Benign bone tissue-forming tumor; similar to osteoid osteoma ▪ Comprises many osteoid (not yet mineralized bone tissue), fibrous (woven) bone-producing osteoblasts ▪ May break bone cortex, grow to adjacent soft tissue Figure 108.7 The histological appearance of an osteoblastoma. There is abundant osteoid and woven bone forming trabeculae which are lined by a single layer of osteoblasts. OSMOSIS.ORG 611
SIGNS & SYMPTOMS ▪ Commonly affects posterior spine, long bones (e.g. femur, tibia) ▪ Dull pain (exacerbated at night) ▪ Not responsive to salicylates ▪ Structural malformations (e.g. scoliosis) ▪ Spinal cord, nerve compression → pain, function loss ▪ Swelling, tenderness, ↓ range of motion DIAGNOSIS DIAGNOSTIC IMAGING X-ray/CT scan ▪ Well defined lucent mass ▪ >2cm/0.79in; no periosteal reaction (differs from osteoid osteoma); if arising from cortical bone → thin new bone layer covering ▪ Adjacent sclerosis ▪ Inner calcification MRI ▪ Assess surrounding structure volume, relationship Figure 108.8 A CT scan of the lower leg in the axial plane demonstrating an osteoblastoma of the fibula. OTHER DIAGNOSTICS Biopsy ▪ Immature trabeculae with single osteoblast layer ▪ High dilated blood vessel number ▪ Distinguish from osteosarcoma ▫ ↓ mitotic activity ▫ ↓ cell atypia ▫ No cartilaginous matrix ▫ Does not imbue surrounding bone, soft tissue TREATMENT SURGERY ▪ Excision 612 OSMOSIS.ORG
Chapter 108 Bone Tumors OSTEOID OSTEOMA osms.it/osteoid-osteoma PATHOLOGY & CAUSES ▪ Bone tissue-forming tumor ▫ Benign, similar to osteoblastoma ▪ Tumor mass (nidus) ▫ Good blood supply, comprised of osteoblasts providing osteoid, fibrous bone ▫ Osteoblasts → ↑ prostaglandin E₂ → pain ▪ Nidus produces/envelopes itself in reactive bone SIGNS & SYMPTOMS ▪ Commonly affects lower-extremity long bones (e.g. femur, tibia), phalanges, spine ▪ Very intense pain (exacerbated at night) ▪ Responsive to salicylates ▪ Painful scoliosis ▪ Swelling, tenderness DIAGNOSIS DIAGNOSTIC IMAGING X-ray/CT scan ▪ Well-defined lucent nidus ▫ Surrounded by reactive bone, <2cm/0.79in in size (differs from osteoblastoma), central mineralization Scintigraphy ▪ Higher central uptake MRI ▪ Nidus ▫ Hard to identify TREATMENT MEDICATIONS ▪ Pain medications (e.g. salicylates, NSAIDs) SURGERY ▪ CT scan-guided radiofrequency ablation ▪ Removal Figure 108.9 The histological appearance of an osteoid osteoma. There is woven bone surrounded by osteoblasts with numerous osteoclasts also present. OSMOSIS.ORG 613
OSTEOSARCOMA osms.it/osteosarcoma PATHOLOGY & CAUSES ▪ Malignant bone tissue-forming bone tumor ▪ Growth plates with mutation-prone cells due to proliferation ▪ Chromosomal aberrations; oncogenes, tumor suppressor mutations ▫ Retinoblastoma gene (RB): cell cycle regulator ▫ Tumor protein 53 (p53): DNA repair, cell apoptosis COMPLICATIONS ▪ Due to tumor growth ▫ Bone marrow repression, cortical bone breakage, adjacent-joint spread SIGNS & SYMPTOMS ▪ Appears in long bones, usually around knee (e.g. distal femur, proximal tibia) ▪ Pain exacerbated by movement; lowered motion range; growing palpable mass; swelling, lymphadenopathy; pathologic fracture Figure 108.10 An X-ray image of the leg demonstrating a ill-defined, radiolucent lesion at the distal diaphysis and metaphysis of the femur. The tumor was histologically proven to be an osteosarcoma. DIAGNOSIS DIAGNOSTIC IMAGING X-ray ▪ Soft tissue mass with different calcification range ▪ Bone destruction ▪ Codman triangle ▫ Periosteal reaction (tumor mass lifts periosteum) ▪ Permeative process in bone (endosteum appears “moth-eaten”) MRI ▪ Assess tumor stage, relation to other structures → precise surgical removal Figure 108.11 The histological appearance of an osteosarcoma. There are numerous malignant spindle cells producing osteoid. 614 OSMOSIS.ORG PET scan ▪ Look for metastases → ↑ radionuclide uptake
Chapter 108 Bone Tumors OTHER DIAGNOSTICS ▪ Biopsy, histologic findings ▫ Tumor cells produce bone tissue ▫ Cell shape/size differs (big cells with hyperchromatic nuclei are dominant) ▫ Abnormal mitoses TREATMENT MEDICATIONS ▪ Preoperative chemotherapy (neoadjuvant) SURGERY ▪ Surgical removal Figure 108.12 An MRI scan of the leg from the same individual. The tumor is seen to extend beyond the cortex of the bone. Figure 108.13 The gross pathological appearance of an osteosarcoma of the femur. The tumor is bulky, with a gritty cut surface and cystic degeneration. OSMOSIS.ORG 615

Osmosis High-Yield Notes

This Osmosis High-Yield Note provides an overview of Bone tumors essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Bone tumors by visiting the associated Learn Page.