Lepra cells are –
**Core Concept**
Lepra cells, also known as Virchow cells, are a histopathological feature seen in leprosy, a chronic bacterial infection caused by Mycobacterium leprae. They are characterized by the presence of foamy macrophages containing acid-fast bacilli, which are a hallmark of the disease.
**Why the Correct Answer is Right**
Lepra cells are formed when macrophages engulf and digest M. leprae, but the bacteria resist digestion and accumulate within the macrophage, causing it to become enlarged and foamy. This process is a result of the phagolysosomal fusion, where the macrophage attempts to contain the bacteria but ultimately fails, leading to the characteristic appearance of lepra cells under the microscope. The presence of lepra cells is a key diagnostic feature of leprosy, particularly in the borderline forms of the disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the characteristic histopathological feature of leprosy.
**Option B:** This option is incorrect because it refers to a different type of cellular reaction seen in other inflammatory conditions, not leprosy.
**Option C:** This option is incorrect because it describes a feature seen in other diseases, not leprosy.
**Clinical Pearl / High-Yield Fact**
Lepra cells are a key diagnostic feature of leprosy, particularly in the borderline forms of the disease. They are characterized by the presence of foamy macrophages containing acid-fast bacilli, which can be seen on histopathological examination of skin or nerve biopsies.
**Correct Answer:** C.