Granularity of oncocyte is due to?
**Core Concept**
The granularity of oncocytes refers to the characteristic appearance of these cells under a microscope, characterized by a finely granular cytoplasm due to the accumulation of mitochondria. This phenomenon is a result of the increased metabolic activity and oxidative phosphorylation in oncocytes.
**Why the Correct Answer is Right**
Oncocytes, also known as Hurthle cells, are a type of epithelial cell that is commonly found in the thyroid gland. The granularity of oncocytes is due to the presence of numerous mitochondria, which are the site of oxidative phosphorylation and energy production. As a result, the cytoplasm of oncocytes appears finely granular under a microscope. The increased number of mitochondria in oncocytes is thought to be an adaptation to the high energy demands of these cells, which are often found in areas of the thyroid gland that are subjected to high levels of oxidative stress.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because oncocytes do not have a characteristic "foamy" appearance, which is more typical of foam cells found in atherosclerotic plaques.
**Option B:** This option is incorrect because the granularity of oncocytes is not due to the presence of lipid droplets, which would give the cells a foamy appearance.
**Option C:** This option is incorrect because the granularity of oncocytes is not due to the presence of glycogen, which would give the cells a more diffuse and eosinophilic appearance.
**Clinical Pearl / High-Yield Fact**
Oncocytes are often found in areas of the thyroid gland that are subjected to high levels of oxidative stress, and are thought to be an adaptation to these environmental conditions. The granularity of oncocytes is a characteristic feature of these cells that can be used to diagnose thyroid pathology.
**Correct Answer: C. Accumulation of mitochondria.**