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Anatomic pathology > Bones & Joints > Flashcards

Flashcards in Bones & Joints Deck (253)
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120

Epiphyseal tumors.

Chondroblastoma.

Clear-cell chondrosarcoma.

Giant-cell tumor of bone.

121

Chondroblastoma: Age group.

Skeletally immature patients.

95% occur between the ages of 5 and 25.

122

Chondroblastoma: Sites (3).

Epiphysis:

- Distal femur.
- Proximal tibia.
- Proximal humerus.

123

Chondroblastoma: Radiography (3).

Lytic mass rimmed by sclerotic bone.

Variable calcification.

No marked periosteal reaction.

124

Chondroblastoma: Cellular components (3).

Stromal cells (immature chondroblasts): "Fried-egg" appearance.

Multinucleate giant cells.

Chondrocytes in a chondroid matrix.

125

Chondroblastoma: Variant cytology (2).

Stromal cells may

- Form syncytia.
- Show nuclear enlargement with atypia.

126

Chondroblastoma: Patterns of calcification (2).

Chicken-wire calcification around the stromal cells.

Coarse calcification of the chondroid matrix.

127

Chondroblastoma: Immunohistochemstry.

S100

- Highlights the stromal cells.
- May be useful in tumors that are obscured by secondary aneurysmal bone cyst.

128

Chondroblastoma vs. chondromyxoid fibroma (3).

Chondromyxoid fibroma:

- Metaphyseal.
- No calcifications.
- More myxoid matrix.

129

Chondroblastoma vs. giant-cell tumor of bone (2).

Giant-cell tumor of bone:

- Stromal cells do not express S100 and have no nuclear grooves.
- No chondroid matrix.

130

Chondroblastoma vs. clear-cell chondrosarcoma (3).

Clear-cell chondrosarcoma:

- Usually in older patients.
- Malignant chondrocytes.
- More calcification.

131

Chondromyxoid fibroma: Sites.

Metaphyseal:

- Distal femur.
- Proximal tibia.
- Pelvis.

132

Chondromyxoid fibroma: Radiography (3).

Completely lytic.

Well-defined, scalloped margins.

Calcifications are not evident.

133

Chondromyxoid fibroma: Histology (4).

Lobules of spindle or stellate cells in a myxoid matrix.

Periphery of lobules is hypercellular; cells resemble chondroblasts.

Fibrovascular separates lobules and may contain osteoid.

Calcifications may obscure architecture.

134

Chondromyxoid fibroma: Cytology (3).

Bizarre cells in some cases.

Few or no mitotic figures.

Multinucleate giant cells in the fibrovascular stroma.

135

Chondromyxoid fibroma: Mutation.

Recurrent anomalies of 6q25.

136

Chondromyxoid fibroma vs. intramedullary chondrosarcoma: Radiography (2).

Intramedullary chondrosarcoma:

- Visible calcifications.
- Poor circumscription.

137

Chondromyxoid fibroma vs. intramedullary chondrosarcoma: Histology (2).

Intramedullary chondrosarcoma:

- Many mitotic figures.
- Usually no multinucleate giant cells in the fibrovascular stroma.

138

Intramedullary chondrosarcoma: Sites (4).

Pelvis.

Ribs.

Proximal femur.

Proximal humerus.

139

Intramedullary chondrosarcoma: Radiography (3).

Radiolucent.

Variable calcification.

No periosteal reaction.

140

Intramedullary chondrosarcoma: Gross pathology.

Lobulated mass that resembles cartilage.

Presence of fleshy tissue indicates high-grade component.

141

Intramedullary chondrosarcoma: Cytology features chondrocytes that indicate malignancy (3).

Open chromatin, visible nucleoli, mitotic figures.

142

Intramedullary chondrosarcoma: Other cytologic features (2).

Chondrocytes form clusters and may contain many nuclei.

143

Intramedullary chondrosarcoma: Grade 1 (4).

Low cellularity.

Rare multinucleate chondrocytes.

Small, dark nuclei.

No mitotic figures.

144

Intramedullary chondrosarcoma: Grade 2 (4).

Increased cellularity at the periphery.

More multinucleate chondrocytes.

Mild nuclear atypia.

Rare mitotic figures.

145

Intramedullary chondrosarcoma: Grade 3 (4).

Increased cellularity overall.

Large, pleomorphic nuclei with visible nucleoli.

More mitotic figures.

There may be much necrosis.

146

Intramedullary chondrosarcoma: Immunohistochemistry.

Poorly differentiated foci may not express S100.

147

Intramedullary chondrosarcoma: Ploidy.

Grade 1: Diploid.

Grade 2: Diploid or aneuploid.

Grade 3: Aneuploid.

148

Intramedullary chondrosarcoma: Other cytogenetic abnormalities (2).

+20q, +8q.

149

Intramedullary chondrosarcoma, grade 1, vs. enchondroma.

Enchondroma:

- Normal hematopoietic tissue separates the lobules of chondroid tissue.
- Distinction requires correlation with clinical and radiologic impression.