According to the Enneking system, not true regarding an active benign tumour is –
**Core Concept**
The Enneking system is a staging system used to classify musculoskeletal tumors, particularly bone and soft tissue sarcomas. It takes into account the tumor's biological behavior and the patient's surgical margin status. The system has two main components: the surgical margin and the tumor's histological grade.
**Why the Correct Answer is Right**
The Enneking system classifies tumors as either "active" or "latent" based on their biological behavior. Active tumors are those that have a higher potential for growth and recurrence, whereas latent tumors are less aggressive. According to the Enneking system, active benign tumors are characterized by a high cellularity, a high rate of mitotic activity, and a potential for local recurrence. The system considers the tumor's histological grade, which is based on the degree of cellular differentiation and the presence of mitotic activity.
**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because the Enneking system does not consider the tumor's size as a factor in determining its biological behavior. Tumors of varying sizes can be classified as either active or latent based on their histological characteristics.
* **Option B:** Incorrect because the Enneking system does not take into account the patient's age or sex when classifying tumors. The system is based solely on the tumor's histological characteristics and the patient's surgical margin status.
* **Option C:** Incorrect because the Enneking system does not consider the tumor's location as a factor in determining its biological behavior. Tumors located in different parts of the body can be classified as either active or latent based on their histological characteristics.
**Clinical Pearl / High-Yield Fact**
When using the Enneking system, it's essential to remember that the tumor's histological grade is a critical factor in determining its biological behavior. A tumor with a high histological grade is more likely to be classified as active and have a higher potential for local recurrence.
**Correct Answer:** A.