Musculoskeletal Neoplasms Imaging Atlas

1. Nomenclature:
1. Osteoid: organic molecules that form non-mineralized matrix
2. Bone Structure:
1. Cortex:
1. Periosteum: (2 layers of cells, inner having osteoproductive potential)
1. Benign periostitis
1. Thick, wavyform, uniform
2. Causes => venous stasis, ischemia, hypertrophic pulmonary osteoarthropathy, thyroid acropachy
   
2. Haversian: (central blood vessel in haversian canal) Osteoblasts and osteoclasts change periosteum into haversian bone.
3. Endosteum: Thin layer of inner portion between haversian system and trabecula restructures haversian system into trabecular system.
2. Cancellous = trabecular bone
3. Bone marrow = hematopoietic and stroma (adipocytes from same precursor as osteoblasts)
3. Bone Lesions:
1. Agressiveness:
1. Expansile with sclerosis: slow growing
2. Non-expansile, no sclerosis: aggressive
3. Malignancy: wide transition zone, cortical destruction, periosteal reaction
2. Benign vs. malignant
1. Cortical destruction or thinning in benign: infection, EG, ABC, fibrous and cartilaginous lesions.
2. Periostitis
1. Benign = thick, dense, wavy
2. Malignant = lamellated (onion-skinned), amorphous, sunburst.
3. EG, ABC, OO, trauma can look malignant. If looks benign, likely to be benign.
3. Normal periosteal reaction occurs in infants 2-6 months of age.
4. Zone of transition: narrow vs. wide. Sclerotic is narrow. Permeative is wide (Round cell = MM, reticulum cell sarcoma (bone lymphoma), Ewing's). Other permeative is infection and EG. Aggressive not necessarily malignant.
1. Benign by age
1. <30: Cystic: EG, ABC, NOF, chondroblastoma, solitary bone cyst; Osteosclerotic: osteoid osteoma, osteoblastoma
2. Malignant by age:
1. 1-30: Ewing's sarcoma, osteosarcoma
2. 30-40: GCT, parosteal sarcoma, fibrosarcoma, MFH, reticulum cell sarcoma
3. >40: Chondrosarcoma, metastatic disease, myeloma
4. Lytic lesion, old patient (MMOL): multiple myeloma, mets, osteosarcoma, lymphoma
3. By osseous site:
1. Epiphyseal
   
1. Peds (ICE)
   
1. Infection
2. Chondroblastoma
3. EG
2. Adults (GMC-C)
1. GCT
2. Metastasis
3. Cysts (ganglion, subchondral, geodes)
4. Clear cell chondrosarcoma
2. Metaphysis
   
1. High-grade osteosarcoma
2. Osteoblastoma
3. Chondromyxoid fibroma
4. Osteochondroma
5. Metaphyseal enlargement (Ehrlenmeyer flask deformity)
3. Metadiaphysis
1. Peds
1. Benign cortical defect/NOF
   
4. Diaphysis malignant round cell (40% of Ewing's), fibrous dysplasia, NOF, simple cyst, ABC, 75% of osteoblastomas
1. Metastases
2. Ewings sarcoma
3. Chondrosarcoma
   
4. By Bone:
1. Tibia: Adamantinoma, juvenile adamantinoma (ossifying fibroma), 28% of chondromyxoid fibroma, osteofibrous dysplasia.
2. Femur and tibia: osteoid osteoma
3. Posterior femur: parosteal osteosarcoma, cortical desmoid (avulsion injury)
4. Post vertebral elements: osteoblastoma
5. Calvarium, vertebra, jaws: hemangioma
6. Mandible and maxilla: ameloblastoma
7. Sacrum:
1. GCT
2. ABC
3. Osteoblastoma
4. Hemangioma
5. Osteochondroma
6. Chordoma
7. MM
8. Lymphoma
9. Ewing (PNET)
10. Chondrosarcoma
11. Osteosarcoma
12. Angiosarcoma
5. Lytic:
1. Benign (FENGOMASCHIC):
1. <30: EG, ABC, NOF, chondroblastoma, solitary bone cyst
2. Epiphyseal: Chondroblastoma, GCT, infection, Geode, (EG, ABC)
3. No periostitis
1. Fibrous dysplasia
2. Enchondroma
3. NOF
4. Solitary bone cyst
1. No calcifications on plain films (lipoma calcifies)
   
4. Multiple: Fibrous dysplasia, EG, enchondroma, high PTH, infection, (mets, myeloma)
   
5. Rib lesions: fibrous dysplasia, ABC, enchondroma, EG, (mets, myeloma)
   
2. Malignant: Mets, Myeloma
6. Matrix:
1. Osteoid matrix.
   
1. Benign (OBOOO)
   
1. Osteoma
   
1. Usually found in calvaria and paranasal sinuses
   
2. Bone island (enostosis)
1. Osteopoikilosis - multiple bone islands clustered around joints.
   
3. Osteoid Osteoma
1. Cortex of tubular bones is most common location
2. Nidus is composed of highly vascular fibrous tissue, osteoid and immature bone
3. Sclerotic reaction
1. Maybe away from the lesion if nidus is intraarticular, similar to remote periosteal reaction in chondroblastoma (no periosteum in the joints)
   
4. Osteoblastoma
1. Similar to osteoid osteoma, but nidus measures > 2cm
2. May rarely undergo malignant transformation
5. Ossifying fibroma
1. Found in anterior proximal tibia
2. Diff Dx
1. Adamantimoma
2. Cortical fibrous dysplasia
   
2. Malignant
1. Osteosarcomas
1. Conventional (central)
   
2. Telangiectatic
1. Fluid-fluid levels
3. Parosteal (surface)
   
1. Found in posterior distal femoral metaphysis, proximal tibia or proximal humerus
2. Cleavage plane between tumor and adjacent bone is usually seen
4. Periosteal (surface)
   
1. Usually diaphyseal in location
2. Causes scalloping
5. Soft tissue osteosarcoma
   
2. Cartilaginous
1. Enchondroma (arcs and rings calcifications)
   
1. Ollier's disease
2. Mafucci's syndrome
2. Osteochondroma (exostosis)
1. Multiple hereditary osteochondromas
2. Dysplasia epiphysealis hemimelica (Trevor disease)
1. Intra-articular epiphyseal osteochondromas
3. Juxtacortical chondroma
1. DiffDx: periosteal osteosarcoma
4. Chonroblastoma
1. Found exclusively in the epiphysis with open physis
2. In older patients, clear cell chondrosarcoma should be considered
   
5. Chonromyxoid fibroma
6. Chondrosarcoma
   
3. Fibrous
1. Fibrous dysplasia
1. Long ground glass lesion in a long bone
   
2. McCune-Albright syndrome
1. Coast of Maine
2. Hormonal disorder
   
2. Fibrous cortical defect/NOF
1. Bubbly lytic cortical lesion with sclerotic margin
   
3. Malignant fibrous histiocytoma
1. Can involve soft tissue or bone
4. Marrow and mets
1. Ewing's sarcoma
1. Most are lytic (permeative)
2. May have some reactive bony sclerosis (onion-skin periostitis, but can be sunburst or amorphous)
3. Soft tissue component is not calcified
2. Primary Lymphoma
3. Multiple myeloma
4. Mets
1. Lytic: Lung, kidney, breast, thyroid, GI, neuroblastoma
2. Blastic: Prostate, breast, bladder, GI, lung, medulloblastoma
5. Vascular
1. Benign: Hemangioma, lymphangioma, glomus tumor
2. Malignant: Angiosarcoma
6. Miscellaneous
1. Peripheral nerve sheath tumors
2. Morton's neuroma
3. Giant cell tumor of tendon sheath
4. Synovial cell sarcoma
5. Giant cell tumor (osteoclastoma)
1. Occur after epiphyseal closure
2. Originates in metaphyses and extends into epiphyses
   
6. Solitary bone cyst
1. Fallen fragment sign
   
7. ABC
8. LCH
1. Vertebra plana
   
9. Brown tumor of hyperparathyroidism
1. Local accumulations of osteoclasts
   
10. Myositis ossificans
1. Matures in the periphery first (paraosteal osteosarcoma shows denser calcification in the center)
   
11. Chordoma
12. Adamantinoma
13. Ganglion cyst
1. Loculated collections of viscous fluid
   
7. Diffuse osteosclerosis
1. Short list (3MSPROF)
1. Myelofibrosis
2. Mastocytosis
3. Metastasis
4. Sickle Cell Disease
   
5. Pyknodysostosis
6. Renal osteodystrophy
7. Osteopetrosis
8. Fluorosis
   
2. Long List
1. Metastases
2. Myelofibrosis
3. Mastocytosis
4. Melorheostosis
1. Thickened cortical bone
2. Wax on a candle appearance
   
5. Pyknodysostosis
6. Paget
7. Phosphorus poisoning
8. Renal osteodystrophy
9. Sickle cell disease
10. Tuberous sclerosis
11. Osteopetrosis
12. Fluorosis
13. Hypervitaminosis D
14. Hypothyroidism