Which of the following lesions does not give blood on aspiration?
**Core Concept:** Lesions that do not give blood on aspiration are those that do not contain blood vessels or are devoid of vascularity. In medical terminology, these lesions are termed as **non-vascular**.
**Why the Correct Answer is Right:** The correct answer, **D. Abscess**, is a non-vascular lesion. An abscess is a localized collection of pus (a mixture of dead white blood cells, bacteria, and cellular debris) that forms as a result of a localized infection. It is typically caused by bacterial invasion of the surrounding tissues, leading to inflammation and destruction of blood vessels, thus rendering the lesion non-vascular.
**Why Each Wrong Option is Incorrect:**
A. **Haematoma:** A haematoma is a collection of blood outside blood vessels, often due to trauma or surgery. Haematomas are vascular lesions because they contain blood, which is essential for clotting and healing processes.
B. **Subcutaneous fat:** Subcutaneous fat is a layer of adipose tissue located just beneath the skin. Although it contains adipocytes, it does not contain blood vessels, making it a non-vascular lesion.
C. **Haemangioma:** A haemangioma is a benign vascular lesion caused by the overgrowth of capillaries and veins. It is a vascular lesion and contains blood, so it does not meet the criteria for the question.
**Clinical Pearl:** Understanding the distinction between vascular and non-vascular lesions is crucial in diagnosing and managing lesions accurately. Non-vascular lesions are generally benign, while vascular lesions can be more complex and may require surgical intervention or other treatment options.
**Correct Answer:** D. Abscess. Abscesses are non-vascular lesions, as they lack blood vessels and contain pus instead of blood. When a non-vascular lesion is aspirated, it does not give blood on aspiration.