Pathology of bone and mesenchymal differentiation all

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of giant cells in bone tumors?

Resorption of bone (correct)

Maintenance of bone growth

Production of bone matrix

Regulation of bone density

Which of the following is a characteristic of giant cell tumor of bone?

Predominance in older adults

Preferential location in the metaphysis or epiphysis (correct)

High metastatic potential

Occurrence in the skull

What is the significance of the mononuclear cell compartment in histological evaluation of giant cell tumor?

It comprises the tumor cells (correct)

It is the primary source of bone matrix

It is responsible for bone resorption

It provides information on the size and distribution of giant cells

Which of the following is a feature of giant cell-containing lesions of bone?

Most are not malignant Signup and view all the answers

What is the typical age range for giant cell tumor of bone occurrence?

Young adults Signup and view all the answers

What is the characteristic distribution of giant cells in giant cell tumor of bone?

Equally distributed Signup and view all the answers

Which of the following is a common location for giant cell tumor of bone?

Knee area Signup and view all the answers

What is the significance of giant cell tumor being intermediate in behavior?

It is locally aggressive and rarely metastasizing Signup and view all the answers

What is a characteristic of osteoclast-like giant cells?

They have more nuclei per cell Signup and view all the answers

What is the function of osteoclasts in bone remodeling?

To absorb and resorb bone Signup and view all the answers

What is the hallmark mutation of giant cell tumor of bone (GCTB)?

H3F3A G34 Signup and view all the answers

What is the significance of the antibody for the mutant protein in H3F3A?

It can distinguish GCTB from chondroblastoma Signup and view all the answers

What is the characteristic of mononuclear cells in giant cell tumor of bone?

They are negative for H3F3A mutation Signup and view all the answers

How can solid aneurysmal bone cyst (ABC) be distinguished from giant cell tumor of bone?

By the presence of USP6 rearrangement Signup and view all the answers

What is the treatment for giant cell tumor of bone?

Curettage and excision Signup and view all the answers

What is the rate of lung metastases in giant cell tumor of bone?

Rare (less than 5%) Signup and view all the answers

What is the primary characteristic of giant cell tumors in terms of their behavior?

They are intermediate because they are locally aggressive and rarely metastasizing Signup and view all the answers

What is the typical location of giant cell tumors in the bone?

In the metaphysis or epiphysis of the bone Signup and view all the answers

What is the significance of the giant cells in histological evaluation?

They are equally distributed and provide information about the tumor's size Signup and view all the answers

What is the preferred location for giant cell tumors in the body?

Knee area and sacrum Signup and view all the answers

What is the characteristic of giant cell-containing lesions of bone?

They can be reactive, metabolic, or neoplastic Signup and view all the answers

What is the main difference between osteoclasts and osteoclast-like giant cells?

The number of nuclei per cell Signup and view all the answers

What is the significance of the mononuclear cell compartment in giant cell tumor?

It provides morphological criteria for the tumor Signup and view all the answers

What is the purpose of the deposition of H+ in the Howships lacuna?

To take away the minerals of the bone Signup and view all the answers

What is the typical age range for giant cell tumors?

Young adults Signup and view all the answers

What is the percentage of giant cell tumors that have H3F3A G34 mutations?

92% Signup and view all the answers

What is the significance of the giant cell's distribution in giant cell tumor?

It is equally distributed and provides information about the tumor's size Signup and view all the answers

What is the significance of the antibody for the mutant protein in H3F3A?

It is used to distinguish GCTB from CB Signup and view all the answers

What is the main difference between GCTB and CB?

The type of mutation in the histone H3.3 protein Signup and view all the answers

What is the characteristic of the mononuclear cells in giant cell tumor of bone?

They are attracted to the tumor but are not tumor cells themselves Signup and view all the answers

What is the significance of the USP6 rearrangement in solid aneurysmal bone cyst (ABC)?

It is used to distinguish ABC from GCTB Signup and view all the answers

What is the treatment for giant cell tumor of bone?

Curettage and excision Signup and view all the answers

Study Notes

Giant Cell Containing Lesions in Bone

Not all giant cell-containing lesions are giant cell tumors; many types of tumors can contain giant cells.
Giant cell tumors are intermediate, locally aggressive, and rarely metastasizing.
Most giant cell-containing tumors are not malignant.
Almost any kind of lesion in bone can contain giant cells, sometimes numerous.

Non-malignant Giant Cell Containing Lesions of Bone

Group includes reactive, metabolic, and neoplastic lesions.

Location in Bone

Some tumors are only found in certain regions of the bone.
Giant cell tumors are typically found in the end of the bone (metaphysis or epiphysis).

Giant Cell Tumor of Bone

Giant cell tumors mostly occur after closure of the growth plate.
They occur in young adults, with a slight preference for females.
Preferential locations include the knee area, sacrum, distal radius, but never in the skull.
Histological evaluation is based on morphological criteria of the mononuclear cell compartment, with an exception for the size and distribution of giant cells.

Bone Cells Involved in Remodeling

Osteoclasts are normally involved in bone remodeling.
Other bone cells involved include osteoprogenitor cells (MSC), osteoblasts and lining cells, osteocytes, and osteoclasts.

Osteoclast Function

Osteoclasts absorb bone, creating an acid environment that removes minerals from the bone.
They have a specific structure, including the Howship's lacuna.

Giant Cell Tumor of Bone

Three cell types are involved: stromal cells, mononuclear cells, and multinuclear cells.
Sometimes, spindle cell changes or bone deposition (metaplastic bone formation) can be seen.

Malignancy in Giant Cell Tumors

Giant cell tumor of bone is intermediate, with a small percentage being malignant.
Primary malignancy: high-grade sarcoma arising in/next to a giant cell tumor.
Secondary malignancy: rare, with end of chromosomes sticking together.
Mutation: H3F3A G34, which is a driver mutation and hallmark of GCTB.

Mutation Detection and Diagnosis

H3F3A G34 mutations are found in 92% of giant cell tumors.
H3F3B K36M mutations are found in 95% of chondroblastomas.
Antibodies can be used to detect these mutations (IHC).
The antibody is specific for G34W (in H3F3A) and K36M (in H3F3B).

Differential Diagnosis

Solid aneurysmal bone cyst (ABC) versus giant cell tumor: molecular diagnostics can be used to distinguish them.
Solid ABC: ~60% USP6 rearrangement, no H3F3A mutation.
GCTB: 69-96% H3F3A mutations, no USP6 rearrangements.

Treatment of Giant Cell Tumor of Bone

Locally aggressive, with often local recurrences (40-60%).
Lung metastases are rare.
Treatment options: curettage, excision.

Giant Cell Containing Lesions in Bone

Not all giant cell-containing lesions are giant cell tumors; many types of tumors can contain giant cells.
Giant cell tumors are intermediate, locally aggressive, and rarely metastasizing.
Most giant cell-containing tumors are not malignant.
Almost any kind of lesion in bone can contain giant cells, sometimes numerous.

Non-malignant Giant Cell Containing Lesions of Bone

Group includes reactive, metabolic, and neoplastic lesions.

Location in Bone

Some tumors are only found in certain regions of the bone.
Giant cell tumors are typically found in the end of the bone (metaphysis or epiphysis).

Giant Cell Tumor of Bone

Giant cell tumors mostly occur after closure of the growth plate.
They occur in young adults, with a slight preference for females.
Preferential locations include the knee area, sacrum, distal radius, but never in the skull.
Histological evaluation is based on morphological criteria of the mononuclear cell compartment, with an exception for the size and distribution of giant cells.

Bone Cells Involved in Remodeling

Osteoclasts are normally involved in bone remodeling.
Other bone cells involved include osteoprogenitor cells (MSC), osteoblasts and lining cells, osteocytes, and osteoclasts.

Osteoclast Function

Osteoclasts absorb bone, creating an acid environment that removes minerals from the bone.
They have a specific structure, including the Howship's lacuna.

Giant Cell Tumor of Bone

Three cell types are involved: stromal cells, mononuclear cells, and multinuclear cells.
Sometimes, spindle cell changes or bone deposition (metaplastic bone formation) can be seen.

Malignancy in Giant Cell Tumors

Giant cell tumor of bone is intermediate, with a small percentage being malignant.
Primary malignancy: high-grade sarcoma arising in/next to a giant cell tumor.
Secondary malignancy: rare, with end of chromosomes sticking together.
Mutation: H3F3A G34, which is a driver mutation and hallmark of GCTB.

Mutation Detection and Diagnosis

H3F3A G34 mutations are found in 92% of giant cell tumors.
H3F3B K36M mutations are found in 95% of chondroblastomas.
Antibodies can be used to detect these mutations (IHC).
The antibody is specific for G34W (in H3F3A) and K36M (in H3F3B).

Differential Diagnosis

Solid aneurysmal bone cyst (ABC) versus giant cell tumor: molecular diagnostics can be used to distinguish them.
Solid ABC: ~60% USP6 rearrangement, no H3F3A mutation.
GCTB: 69-96% H3F3A mutations, no USP6 rearrangements.

Treatment of Giant Cell Tumor of Bone

Locally aggressive, with often local recurrences (40-60%).
Lung metastases are rare.
Treatment options: curettage, excision.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the biology and characteristics of giant cell tumors, including GCTB, and how to distinguish them from other giant cell containing lesions in bone.