RAD 4001 Case Presentation
Submitted by: Lindsey Fogle, MSIVDate Accepted: 25 August 2010
Faculty Reviewer: Sandra Oldham, M.D.
Principal Modality (1): Plain filmPrincipal Modality (2): MRI T1-weighted
10yo boy with chronic leg pain
Plain film of left tibia and fibula
Findings
Radiolucent nidus in the cortex of distal tibial diaphysis
Nidus surrounded by dense osteosclerosis
Axial cut of T1 post contrast image shows well demarcated, enhancing lesion
Plain film of left tibia and fibula
Axial T1-weighted MRI post contrast
Differential Diagnosis
Focal bone lesion
Increased bone
density
Osteoblastic
Metastases
Prostate, breast,
lymphoma, carcinoid
Chronic Osteomyeli
tis
Paget’s disease
Avascular necrosis
Femor/humeral
head or fx of scaphoidSickle Cell, Polycythemia,
vasculitis, trauma,
steroids/Cushing’s, Legg-Calve-
Perthes dz
Bone neoplasm
Decreased bone
density
Osteolytic Metastases
Renal, thyroid,
lung, breast
Osteomyelitis
Acute or chronic
Multiple Myeloma
Bone neoplasm Bone cyst Fracture
Differential Diagnosis
Benign bone tumors Osteoid osteoma Osteoblastoma Osteochondroma Osteofibrous dysplasia Fibrous dysplasia Enchondroma▪ 20-50yo; M=F; bones of
hands/feet Giant cell tumor▪ 20-40yo; F>M; epiphysis
of distal femur/proximal tibia
Malignant bone tumors Osteosarcoma Chondrosarcoma▪ 30-60yo; M>F; pelvic
bones/proximal femur Ewing's sarcoma
Bone cysts▪ Typically appear lytic,
expansile, with thin surrounding cortical bone
Osteochondroma
M>F; 10-30yo Hamartomatous lesion resulting
from a defect in the growth plate on the metaphyseal side; direct communication with medullary canal; always points away from joint of origin
Pedunculated (distal femur) or sessile (proximal humerus)
Familial form (Hereditary Multiple Exostosis) is AD with diffuse involvement
Findings: cartilaginous cap at bony base is required for diagnosis
Surgery if symptomatic only; most are assymptomatic
Osteofibrous Dysplasia
M>F; ≤ 10yo Usually asymptomatic, but can
cause anterior bowing Suspected to be a hamartomatous
process that involutes Almost exclusively in the
diaphysis of the tibia, but can occur in the fibula or bilaterally
Findings: lytic lesions surrounded by sclerosis -> “soap bubble appearance”
Treat large or symptomatic lesions with curettage and bone grafting
Fibrous dysplasia: F>M; dx typically before 30yo; Inability to produce mature lamellar bone; can be monostotic/polyostotic or polyostotic with endocrine abnormalities (McCune-Albright syndrome); also takes soap bubble appearance -> need histology to differentiate; treatment is same
Osteosarcoma (classic)
M>F; 10-25yo Second most common primary
malignancy of bone after Multiple Myeloma (20% of all primary bone malignancies)
Risk factors include Paget’s disease, Familial retinoblastoma, and radiation
Most in metaphysis of distal femur or proximal tibia; can also be in the proximal humerus
Aggressive, can metastasize to lungs
Findings: Lytic lesion that permeates giving “sunburst” appearance-> breakthrough of periostium results in “Codman triangle”
MRI indicated for staging and anatomic data for surgery
Treat with chemotherapy and surgery
Ewing’s Sarcoma
M>F; 5-25yo Malignant bone lesion Translocation abnormality
involving chomosomes 11 and 22 in 90% of cases
Pelvis is most common location, but also seen in femur, tibia, humerus, and scapula
Typically in diaphyseal-metaphyseal region
Findings: central lytic lesion with extending destruction of cortex; takes “onionskinning” appearance from periosteal reaction
Can resemble osteomyelitis because of high grade nature, necrosis and liquefaction that occur, mistaking it for pus
Radiosensitive tumor, but current treatment also involves surgery
Osteoid Osteoma
Epidemiology 10% of benign bone tumors; most common of the benign tumors M>F; 5-30yo with peak incidence in 2nd decade Most commonly in proximal femur, but also occurs in spine or tibial diaphysis
Pathology Osteoid forming neoplasm <1cm in diameter of benign woven bone in the nidus Nidus contains numerous osteoblasts and osteoclasts in vascular fibrous stroma Note: Osteoblastomas are large Osteoid Osteomas with preference for the posterior spine
Clinical Presentation Usually assymptomatic Night pain or dull, aching pain that is progressive Tenderness over lesion
Classification for all benign tumors Stage 1 – latent; generally asymptomatic; usually resolve on their own Stage 2 – active; less well demarcated; require more aggressive treatment Stage 3 – aggressive lesions; extensive destruction; requires wide en bloc resection
Treatment Pain relieved by NSAIDs
▪ High concentration of prostaglandins in nidus▪ 50% will “burn out” over time
If NSAIDs fail..▪ CT guided radiofrequency ablation (IR)▪ Surgical removal (Ortho)
Typical findings of Osteoid Osteoma
Radiolucent nidus on plain film Measures up to 1cm in
diameter Nidus surrounded by dense,
reactive osteosclerosis if a cortical lesion; creates an extending fusiform bulge Less sclerosis noted with more
central lesions Inflammatory synovitis can
result if adjacent to or in a joint Technetium bone scan is
always positive CT is helpful for anatomic
data in preparing for surgery
CT-guided Radiofrequency Ablation (RFA)
Axial CT without contrast images of left distal tibia and fibula
Pre- and Post-RFA
Axial T1 weighted MRI post contrast images of left distal tibia and fibula
Pre-treatment Post-treatment
References
Herring, William. "Chapter 21: Recognizing Abnormalities of Bone Density." Learning Radiology: Recognizing the Basics. Philadelphia: Mosby Elsevier, 2007. 217-30. Print.
Goljan, Edward F. "Chaprter 23: Musculoskeletal Disorders." Pathology. Philadelphia, PA: Mosby Elsevier, 2007. 522-26. Print.
Polousky John D, Eilert Robert E, "Chapter 24. Orthopedics" (Chapter). Hay WW, Jr., Levin MJ, Sondheimer JM, Deterding RR: CURRENT Diagnosis & Treatment: Pediatrics, 19e: http://www.accessmedicine.com/content.aspx?aID=3405856 .
Randall R. L, Hoang Bang H, "Chapter 6. Musculoskeletal Oncology" (Chapter). Skinner HB: CURRENT Diagnosis & Treatment in Orthopedics, 4e: http://www.accessmedicine.com/content.aspx?aID=2320059.
Srinivasan Ramesh C, Tolhurst Stephen, Vanderhave Kelly L, "Chapter 40. Orthopedic Surgery" (Chapter). Doherty GM: CURRENT Diagnosis & Treatment: Surgery, 13e: http://www.accessmedicine.com/content.aspx?aID=5314010.
Zeiger Roni F, McGraw-Hill's Diagnosaurus 2.0: http://www.accessmedicine.com/diag.aspx
Special thank you to M.D. Anderson Cancer Center for patient’s images.