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Age / Sex : 33 / M
Age / Sex : 33/ M
Chief complaint : Rt thigh pain (10YA)
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of
this case.
* Send Application Answers to In Sook Lee, MD (lis@pusan.ac.kr)
Courtesy : Jung-Ah Choi, Seoul National University Bundang Hospital
Diagnosis: INTRAOSSEOUS WELL DIFFERENTIATED OSTEOSARCOMA
Discussion
Answer:
• Findings: Intramedullary
lobulated mass like lesion at distal femoral shaft metadiaphysis area,
measuring about 2.4x2.4x2.0 cm size with suspicious chondroid matrix and endosteal
scalloping
• On MRI, heterogeneous
SI on T1, high SI on T2WI with strong enhancement
Differential Diagnosis: healing stage of NOF, low grade
chondrosarcoma, enchondroma
Diagnosis:
INTRAOSSEOUS WELL DIFFERENTIATED OSTEOSARCOMA
(low grade central type osteosarcoma)
• Discussion: Uncommon
subtype (<1% of OS cases)
• 30~40대
• Within the
medullary canal of distal fumur and proximal tibia
• 5YSR : 90%
• Histology
– microtrabecular
osseous matrix in a bland fibrous stroma with a variable amount of bone
production
• considered
the intramedullary equivalent of low-grade parosteal OS -> surgical
resection alone
• Image
– expansile
lytic bone destruction with coarsely thick or thin incomplete trabeculation
– cortical
disruption and soft-tissue extension: common
– dense
sclerotic pattern: less common
• DDx
– fibrous
dysplasia, nonossifying fibroma, and desmoplastic fibroma
References: RadioGraphics
2010; 30:1653–1672
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