8 years old Painful Leg, low grade fever
Findings?

Detail View
Findings, DDX, next step?

MRI Correlation
DDX, #1 Choice?

Same Disease, Different Patient.

What is the name for this appearance in bone, and does it favor a benign or malignant process?
Does it alter your DDx?

Answers

• Initial radiographs showed a highly-aggressive, permeative lesion in the proximal tibia, with a wide zone of transition and abdunant overlaying periosteal reaction
• Permeative lesion in a child, DDx: Ewing’s, infection, EG
• MRI (actually from another patient) confirmed an overlaying soft tissue mass and invasion of the marrow cavity
• Final image shows a “laminated” periosteal reaction, which is malignant and often seen in Ewing’s Sarcoma

Ewing’s Information

• Ewing’s is the most common malignant bone tumor in children, 4th most common bone tumor overall
• Peak age 15 year old, 95% occur between 4-25 years old (96% occur in Caucasians)
• ”Small round cell” tumor histologically, very similar to PNET
• Clinical: severe localized pain; soft-tissue mass; fever, leukocytosis, anemia simulating infection
• Location – classically in long bones (60%) and flat bones (40%): femur > pelvis/ilium >tibia > humerus > fibula > ribs
• Mottled “moth-eaten” destructive permeative lesion (72%)
• Early fusiform lamellated “onionskin” periosteal reaction (53%); alt.spiculated “sunburst” periosteal reaction (23%)
• Broad DDx includes: Multiple Myeloma (should be older); Osteomyelitis; eosinophilic granuloma; osteosarcoma (bone forming, no ;lamellated periosteal reaction); reticulum cell sarcoma (30 to 50 year old); neuroblastoma (< age 5); anaplastic metastatic carcinoma