**Core Concept**
Popcorn calcification is a type of dystrophic calcification, a pathological process where calcium deposits form in damaged or necrotic tissues. This phenomenon is often observed in certain types of benign or malignant tumors, where the cellular structure has been disrupted, leading to an accumulation of calcium salts.

**Why the Correct Answer is Right**
Popcorn calcification is specifically associated with osteosarcomas (malignant bone tumors). The characteristic "popcorn" appearance is due to the deposition of calcium phosphate crystals within the tumor cells, giving it a distinctive radiographic appearance. This type of calcification is thought to be the result of the tumor's aggressive growth and the subsequent necrosis of tissue, which creates a favorable environment for calcium deposition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because popcorn calcification is not typically seen in osteochondromas, which are benign bone tumors that originate from the cartilage.
**Option B:** This option is incorrect because dystrophic calcification can occur in a variety of conditions, but popcorn calcification is specifically characteristic of osteosarcomas.
**Option C:** This option is incorrect because while calcifications can be seen in lipomas, the "popcorn" appearance is not a typical feature of this type of tumor.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize the characteristic radiographic appearance of popcorn calcification in osteosarcomas, as it can be a key diagnostic feature in imaging studies.

**Correct Answer: C. Osteosarcoma**