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-Waseem Abu Obeida

-Zaid Emad

-Mousa Al-abbadi

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Cartilage-forming tumors:

1-Osteochondroma (benign exostoses referring to its growth outside

the normal bone structure ) :

Benign tumor contains both bone and cartilage, arise from the

metaphysis near the growth plate of long tubular bones, especially near

the knee (distal femur or proximal tibia).

-Related to EXT1 or EXT2 mutations.

-Macroscopically: cartilage-capped tumor attached to the underlying

skeleton by a bony stalk.

Microscopically: hard to diagnose as osteochondroma, usually appear as

normal bone.

-Osteochondromas usually stop growing at the time of growth plate

closure, but it could be asymptomatic and that’s why it’s lately

diagnosed in adults.

-About 85% are solitary (spontaneous), the remainder are seen as part

of the multiple hereditary exostoses (MHE).

-Cases of osteochondromas that progress to chondrosarcomas are rare

(3-5%), more common in MHE.

-it can be painful if they impinge on a nerve or if the stalk is fractured.

Treatment: symptomatic tumors are removed by surgical excision,

especially if the patient complains from pain, but if you don’t need

surgery don’t do it.

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2-Chondroma (enchondroma):

-Benign hyaline cartilage tumors in bones with endochondral origin,

appears as normal cartilage under the microscope.

-They are called enchondroma if they occur inside the medullary canal

and cortical chondroma if located on the cortical surface.

-if Multiple enchondromas they are called Ollier disease, and Maffucci

syndrome if multiple enchondromas + skin hemangiomatosis ( benign

vascular tumors ) .

-related to IDH1 & IDH2 gene mutations.

-enchondromas are usually diagnosed in individuals 20-50 years ,and

they usually appear as metaphyseal lesions.

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3-CHONDROSARCOMA:

Malignant tumors producing cartilage

• 50% incidence of osteosarcoma (osteosarcoma is the most

common malignant tumor of bone, Ewing sarcoma 2nd,

chondrosarcoma is 3rd excluding hematopoietic tumors (myeloma

and lymphoma)).

• 40-50 years of age, affects men twice as frequently as women.

• Large masses usually around the shoulder, pelvis and ribs.

• Genes: EXT, IDH1, IDH2, COL2A1, CDKN2A. (COL2A1 gene for

making collagen type 2, remember col type2 found in cartilage,

type1 in bone, type4 basement membrane).

Chondrosarcoma is usually a migrating tumor.

• Prognosis and management: depends on grading of tumor (grade

1 -3), grade 1 is the most differentiated and grade 3 is the least

differentiated, grade 1 is the least severe grade so it is good

prognosis. We grade the tumor depending on the whole tumor, so

we say 90% of tumor is grade 1 and the other 10% is grade 2 or 3

for example.

Note: Grading of cancer is based on the degree of differentiation

of tumor cells, staging is based on the size of the primary lesion

and its extent of spreading.

Enchondroma (does not penetrate

the cortex)

Cortical chondroma

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• Treatment: surgical removal then chemotherapy if needed. Grade

1 usually need only surgical removal and grade 2 and 3 need

chemotherapy in addition to surgery.

The problem of chondrosarcoma is that it is large and we need to

take a lot of samples for grading.

Under X-ray it appears as Codman triangle as in osteosarcoma and

Ewing sarcoma.

Codman triangle: is the triangular area of the new sub-periosteal

bone that is created when a lesion, often a tumour, raises the

periosteum away from the bone.

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Tumors of unknown origin:

Ewing sarcoma:

Dr. James Ewing (1866-1943). Described this tumor 1920.

• They are called Small blue cell tumor relating to their appearance

under the microscope with H&E stain, nucleus appears blue with

haematoxylin and cytoplasm appears pink with eosin due to the

presence of mitochondria. (The cell appears blue because of high

nucleus to cytoplasm ratio).Blue cell tumor is not specific for Ewing it is

also present in neuroblastoma, lymphoma and others.

The tumors usually arise in the diaphysis of long tubular bones and most

patients are under 20 years.

• 2nd most common sarcoma of bone after osteosarcoma.

• The most common translocation, present in about 90% of Ewing

sarcoma cases, is t (11; 22) (q24; q12), which generates an aberrant

transcription factor through fusion of the EWSR1 gene with the FLI1

gene (more common) or with FLI2 gene t (21, 22).

• Treatment: neoadjuvant CT followed by surgery; long term survival

now reaches 75%.

It is also called primitive neuroectodermal tumor (PNET).

These sections are features for many

sarcomas and we need other features

for diagnosis for Ewing.

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GIANT CELL TUMOR OF BONE :

Locally aggressive recurrent neoplasm of adults and usually act as benign

tumors, 5-10% could metastasize and act as malignant tumors (Rare

malignant behaviour).

- Usually occur in Epiphyses of long bones.

- Osteoclast-like giant cells (multi-nucleated giant cells 20-50 nuclei)

with single cells in between which have similar nuclei, multi-nucleated

giant cells can occur in any bone tumor, but in this tumor it is the main

indication with no other features for other bone tumor.

- Cells contain high levels of RANKL (this indicates the origin of these

cells are osteoclasts)

- Treatment with curettage.

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ANEURYSMAL BONE CYST: the name indicates cysts of dilated blood

vessels of bone.

• Benign tumor characterized by

blood-filled cystic spaces mainly

and there could be active giant

cells.

• Mainly occur in metaphysis of

long bones in adults.

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Nonossifying Fibroma (NOF)

Proliferation of benign bland fibroblasts inside the bone, and there

was no ossification, it is only fibrous tissue.

Benign lesion, maybe reactive not a true neoplasm (other names:

fibrous cortical defect (FCD), metaphyseal fibrous defects (MFD)).

Metaphysis of adults.

Histology: bland fibroblastic proliferation.

May resolve spontaneously.