Ewing’s tumour arises from-
**Core Concept**
Ewing's tumor is a type of malignant bone cancer that belongs to the family of cancers known as the Ewing's Sarcoma Family of Tumors (ESFT). It is characterized by a specific genetic translocation. The underlying principle being tested here is the **cell of origin** for Ewing's tumor.
**Why the Correct Answer is Right**
Ewing's tumor is believed to arise from **neuroectodermal cells**, which are precursors to nerve cells. This is supported by the presence of specific genetic markers and the tumor's response to certain treatments. The exact cell of origin is still a topic of research, but it is thought to be related to **primitive neuroectodermal cells**.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Ewing's tumor does not arise from epithelial cells.
**Option B:** This option is incorrect because, although Ewing's tumor can occur in bones, it does not arise from osteoblasts or osteoclasts.
**Option D:** This option is incorrect because Ewing's tumor is not thought to arise from mesenchymal stem cells, although it can affect mesenchymal tissues.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that Ewing's tumor often presents with **systemic symptoms** such as fever and weight loss, in addition to local symptoms like bone pain.
**Correct Answer:** D. Neuroectodermal cells