Fish hook pattern of capillaries is seen in
**Core Concept**
The fish hook pattern of capillaries is a characteristic histopathological feature seen in conditions where there is capillary wall thickening, often due to immune complex deposition or vascular damage. This pattern is typically observed in diseases that affect the small blood vessels, such as vasculitis or systemic lupus erythematosus.
**Why the Correct Answer is Right**
The fish hook pattern is caused by the irregular thickening of the capillary wall, which leads to a distinctive "hook-like" appearance. This is often due to the deposition of immune complexes or the proliferation of endothelial cells, resulting in a distorted capillary lumen. The capillary wall thickening can also lead to the formation of a "tram-track" or "railroad track" appearance, further contributing to the characteristic fish hook pattern.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the fish hook pattern is not typically associated with conditions that primarily affect the large blood vessels, such as atherosclerosis.
* **Option B:** This option is incorrect because the fish hook pattern is not a characteristic feature of conditions that primarily affect the lymphatic system, such as lymphoma.
* **Option C:** This option is incorrect because the fish hook pattern is not typically associated with conditions that primarily affect the connective tissue, such as rheumatoid arthritis.
**Clinical Pearl / High-Yield Fact**
The fish hook pattern of capillaries is a classic histopathological feature of systemic lupus erythematosus (SLE), a chronic autoimmune disease that can affect multiple organ systems.
**Correct Answer: D. Lupus Nephritis**