The document provides an overview of malignant bone tumors, focusing on classifications and specifics of various types such as osteosarcoma, chondrosarcoma, and Ewing sarcoma. It details clinical presentations, genetic mutations, histological features, and radiological findings associated with each tumor type. Additionally, the document includes multiple clinical case scenarios and questions related to the diagnosis of these bone tumors.

1. Malignant
bone
tumors

2. Topics to be covered
Classification of Bone Tumors
Chondrosarcoma
Osteosarcoma
Ewing sarcoma

4. Classification of bone tumors
Histologic type Benign Malignant
Osteogenic/ bone
forming
• Osteoma
• Osteoid osteoma
• Osteoblastoma
Osteosarcoma
(primary/ secondary)
Chondrogenic/
Cartilaginous • Osteochondroma
• Chondroma
• Chondroblastoma
Chondrosarcoma

5. HEMATOPOIETIC
• MYELOMA
• MALIGNANT
LYMPHOMA
Unknown origin • Giant cell tumor
• Aneurysmal bone
cyst
Ewing sarcoma
Neuroectodermal
(notochordal)
Chordoma

6. OSTEOSARCOMA
•Most common primary
malignant bone tumor
• Characterized by formation of bone matrix or osteoid
by malignant tumor cells (osteoblast proliferation)
• Stains positive for Alkaline phosphatase and
osteonectin

7. Clinical Presentation
• 10-20 years
Age
• Metaphyses of long bones
Location
• Germline mutation
• Rb gene mutation, TP53 mutation
Genetic (Pathogenesis)

8. Gross and microscopy
•Bulky, gritty and gray-
white
GROSS
•New bone/ osteoid
formation(Single
diagnostic feature)
•Lace like pattern
MICROSCOPY

9. Radiological findings
•A destructive, mixed lytic and blastic mass with infiltrative
margins (Sunburst appearance)

10. • Codman triangle, indicates aggressive tumor(Characteristic but not diagnostic)

11. CASE 1(mcq)
A 20 year old man presented with progressive swelling of
lower end of femur. X-ray shows a characteristic codmans
triangle and CT shows osteoblastic metastasis. Which of
the following is associated with a high risk of the given
clinical condition?
A. Translocation (12:16)
B. Germline mutation of Rb
C. Translocation (x;18)
D. 1p rearrangements

12. CASE 1(mcq)
A 20 year old man presented with progressive swelling of
lower end of femur. X-ray shows a characteristic codmans
triangle and CT shows osteoblastic metastasis. Which of
the following is associated with a high risk of the given
clinical condition?
A. Translocation (12:16)
B. Germline mutation of Rb
C. Translocation (x;18)
D. 1p rearrangements

13. CHONDROSARCOMA
•Malignant tumor of connective tissue
• Sometimes resides
in medullary cavity
of bone
(distinguish this
from
osteochondroma)

14. Clinical Presentation
• 45-60 years
Age
• Pelvis, ribs, sternum, shoulder
Location
• Chr1p re-arrangement, EXT gene mutation
• IDH1 and IDH2(sporadic)
• COL2A1 mutation, Silencing of CDKN2A tumor
suppressor gene
Genetic (pathogenesis)
Painful, progressively enlarging masses

15. GROSS
• Large bulky tumors
• Nodules of greyish white/
light blue transluscent
glistening areas
MICROSCOPY
• Pleomorphic chondrocytes
• Cartilagenous matrix
• Lack of new bone formation

16. Radiological
Presentation
•Shows tumor in medullary cavity
•Poorly defines borders
•Calcified matrix = foci of flocculent densities
with ring like ossifications
•Popcorn calcification

17. CASE 2
A 45 year old female presented with increasing pain and
swelling around the knee. She mentioned that the
symptoms had progressed over a 4-month period.
Pathologic finding in high power view is given below .
DIAGNOSIS?

18. CASE 2
A 45 year old female presented with increasing pain and
swelling around the knee. She mentioned that the
symptoms had progressed over a 4-month period.
Pathologic finding in high power view is given below .
CHONDROSARCOMA

19. EWING’S SARCOMA
•Characterized by primitive round cells without obvious
differentiation.
• IHC marker for EWS
• CD99 or mic 2
• EWS= Undifferentiated tumor
• PNET (Primitive neuroectodermal tumor)= neural
differentiation.

20. Clinical
presentation
•10-20 years
Age
•Diaphysis of long bones
Location

21. •t(11:22) EWSR1
•t(21:22)
Genetic
(pathogenesis)

22. • Soft, grayish white/ tan- white
• Frequently areas of hemorrhage
and necrosis are also seen.
GROSS
• Small, round, blue cells, scanty
cytoplasm(rich in glycogen)
• PAS stain positive
• along with rosettes(HOMER
WRIGHT)
MICROSCOPY

24. Radiological
findings
• X-RAY
•Onion skin
appearance

25. CASE 3 (mcq)
A 10 year old boy presents with fever
and swelling right mid thigh which is
warm and tender. X-rays show a
destructive lytic tumor with permeative
margins that extend into the
surrounding soft tissues with onion skin
appearance. Biopsy is shown.
Diagnosis?

26. CASE 3 (mcq)
A 10 year old boy presents with fever
and swelling right mid thigh which is
warm and tender. X-rays show a
destructive lytic tumor with permeative
margins that extend into the
surrounding soft tissues with onion skin
appearance. Biopsy is shown.
EWING’S SARCOMA

27. Thank you