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.