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Table 1 Differences and similarities between GCT, CB, and ABC of the patella

From: Chondroblastoma of the patella with secondary aneurysmal bone cyst, an easily misdiagnosed bone tumor:a case report with literature review

 

GCT

CB

ABC

Incidence rate

33%

16%

5%

Age (years)

20–40

15–20

10–20

Common location

The distal femur, proximal tibia, and distal radius

Proximal epiphysis of the femur, humerus, and tibia

Epiphysis of the femur and tibia

Clinical presentation

Knee pain

Knee pain

Knee pain

Physical examination

Tenderness

Tenderness

Tenderness

Imaging findings

X: osteolytic lesion, soap bubble appearance, non-sclerotic margin, and radiolucent lesion; CT: osteolytic lesion;

MRI: osteolytic lesion, hypointensity on T1WI, and hyperintensity on T2WI

X: osteolytic lesion with well-defined sclerotic margin, lobulated rims, and thinned cortex;

CT: osteolytic lesion with septation, sclerotic margins, and some intralesional calcifications;

MRI: lobulated lesion, iso/hypointensity on T1WI, and mixed intensity or hyperintensity focus on T2WI

X: geographic osteolysis, smooth borders, thinned cortices, and intact articular surface;

CT: fluid-filled multiseptate cavities without intralesional calcifications;

MRI: lobulated lesion with a fluid-filled cyst, hypointensity on T1WI, and hyperintensity on T2WI

Histone H3.3 mutation

H3F3A

H3F3B

With secondary ABC

Yes

Yes

Pathology

Numerous giant cells, short spindle-shaped cells, bone tissue calcification, and a few mitotic figures

Proliferating chondroblast with chondroid matrix, some multinucleated giant cells, “coffee bean” nucleus

Necrosis and hemorrhagic cystic cavities or red cells

Treatment

Intralesional curettage (benign GCT) or patellectomy with adjuvant treatment (aggressive GCT)

Intralesional curettage followed by bone grafting

Intralesional curettage followed by bone grafting