Krukenberg spindles –
**Core Concept**
Krukenberg spindles are a histopathological finding associated with certain types of **melanocytic lesions**. They are characterized by the presence of **melanin** within the **corneal stroma** and **uveal tract**. This phenomenon is related to the dispersion of **melanin pigment**.
**Why the Correct Answer is Right**
The correct answer relates to the dispersion of **melanin pigment** from the **uveal tract** into the **corneal stroma**, forming Krukenberg spindles. This occurs due to the **melanin phagocytosis** by **corneal stromal cells**. The **uveal melanocytes** produce **melanin**, which can then be dispersed and phagocytosed.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the formation or composition of Krukenberg spindles.
**Option B:** This option is also incorrect as it does not relate to the correct **melanin dispersion** mechanism.
**Option C:** This option is incorrect because it does not accurately describe the **histopathological findings** associated with Krukenberg spindles.
**Option D:** This option is incorrect as it is unrelated to the **melanin phagocytosis** process.
**Clinical Pearl / High-Yield Fact**
Krukenberg spindles are a significant finding in **melanocytic lesions**, particularly in **uveitis** and **melanoma**. Recognizing these spindles can aid in the diagnosis of **ocular melanosis**.
**Correct Answer:** D. Krukenberg spindles are melanin pigment in the corneal stroma.