**Core Concept**
Psammoma bodies are a type of calcification associated with certain types of tumors, particularly papillary thyroid carcinoma and serous ovarian carcinoma. They are characterized by a specific type of calcification that is thought to be a result of the deposition of calcium pyrophosphate dihydrate crystals.

**Why the Correct Answer is Right**
Psammoma bodies exhibit dystrophic calcification, which is a type of calcification that occurs in damaged or dead tissue. This type of calcification is often seen in association with tumors, where there is a disruption of normal cellular processes. The deposition of calcium pyrophosphate dihydrate crystals in psammoma bodies is thought to be a result of the activation of certain enzymes, such as alkaline phosphatase, which catalyze the formation of calcium pyrophosphate.

**Why Each Wrong Option is Incorrect**
* **Option A:** Heterotopic calcification is a type of calcification that occurs in normal tissues, often as a result of abnormal mineralization. This is not characteristic of psammoma bodies.
* **Option B:** Metastatic calcification is a type of calcification that occurs in normal tissues as a result of elevated levels of calcium in the blood. This is not characteristic of psammoma bodies.
* **Option C:** Idiopathic calcification is a type of calcification that occurs in normal tissues without a clear cause. This is not characteristic of psammoma bodies.

**Clinical Pearl / High-Yield Fact**
Psammoma bodies are often seen in association with papillary thyroid carcinoma and serous ovarian carcinoma, and are a useful diagnostic feature in the histopathological examination of these tumors.

**Correct Answer:** C. Dystrophic calcification.