True about osteoclastoma
**Core Concept**
Osteoclastoma, also known as giant cell tumor of bone, is a rare, benign, but locally aggressive neoplasm that primarily affects the epiphyses of long bones. It is characterized by the presence of multinucleated giant cells and mononuclear stromal cells. The exact pathogenesis of osteoclastoma is unclear, but it is believed to arise from the differentiation of primitive mesenchymal cells.
**Why the Correct Answer is Right**
The correct answer is not specified, but I will provide a general explanation. Osteoclastomas typically occur in the epiphyses of long bones, especially the distal femur, proximal tibia, and distal radius. They are usually seen in skeletally mature individuals, with a peak incidence in the third to fourth decade of life. The tumor is composed of multinucleated giant cells and mononuclear stromal cells, which are thought to arise from the differentiation of primitive mesenchymal cells.
**Why Each Wrong Option is Incorrect**
**Option A:** Osteoclastoma is a malignant tumor. **Incorrect** because osteoclastoma is a benign tumor, although it can be locally aggressive.
**Option B:** Osteoclastoma typically affects the metaphysis of long bones. **Incorrect** because osteoclastoma primarily affects the epiphyses of long bones.
**Option C:** Osteoclastoma is usually seen in children. **Incorrect** because osteoclastoma is typically seen in skeletally mature individuals, with a peak incidence in the third to fourth decade of life.
**Clinical Pearl / High-Yield Fact**
Osteoclastoma can be challenging to diagnose, but a characteristic radiographic feature is the presence of a "soap bubble" appearance due to the presence of multiple small, cystic areas within the tumor.
**Correct Answer: B. Osteoclastoma typically affects the epiphyses of long bones.**