Chondrosarcoma of bone can be graded based on the histologic criteria proposed by Evans et al. This can separate tumors into prognostically useful groups.
Features:
(1) cellularity
(2) differentiation
(3) architecture
(4) matrix
(5) nuclei
(6) mitotic activity
(7) necrosis
(8) encasement
(9) other
|
Feature |
Grade 1 |
Grade 2 |
Grade 3 |
|
cellularity |
low, paucicellular |
increased |
markedly increased |
|
differentiation |
well-differentiated hyaline cartilage |
|
limited or no chondroid matrix; spindle cells no longer with features of chondrocytes |
|
lobular architecture |
present |
still present, with fibrovascular septae |
no longer recognizable |
|
muco-myxoid degeneration of matrix |
limited |
increased |
extensive |
|
nuclei |
small, densely staining; chrondocytes bi- or multi-nucleated |
moderate size, paler, have visible intranuclear detail |
|
|
mitotic activity |
0 in 10 HPF |
occasional (< 2 in 10 HPF) |
>= 2 mitoses per 10 HPF in most active areas |
|
necrosis |
none |
foci present |
larger areas |
|
encasement |
may be present |
sporadic |
|
|
other |
calcification and bone formation often present |
|
increased vascularity |
where:
• HPF = high power microscopic field (40x objective). Mitotic counts are affected by the area of the visual field, which varies with each microscope.
• Evans et al states that a Grade II chrondrosarcoma should have < 2 mitoses in 10 HPF (page 822). The table in Bovee and Hogendoom give list "> 2 mitoses per HPF".
Interpretation:
• The higher the grade, the worse the prognosis.
• High grade tumors have a higher rate of local recurrence.
|
Grade |
5 Year Survival |
10 Year Survival |
Metastasis |
|
I |
90% |
83% |
0% |
|
II |
81% |
64% |
10% |
|
III |
43% |
29% |
71% |
(according to Evans et al page 826 and Table 1, page 827; Bovee and Hogendoorn refer to the 5 year survival rates as 10 year survival on page 228)
Limitations:
• Histologic classification is based on the most active area. A tumor may show a variation in histologic appearances, so that extensive sampling is recommended to identify the most aggressive area.
• Chondrosarcomas arising in phalangeal bones may have high grade features yet behave with a relatively indolent clinical course.
Specialty: Hematology Oncology, Surgery, general, Surgery, orthopedic
