**Psammoma Bodies**

**Core Concept**
Psammoma bodies are small, concentrically laminated calcifications found within certain types of tumors. They are a result of dystrophic calcification, where calcium deposits form in damaged or necrotic tissues.

**Why the Correct Answer is Right**
Psammoma bodies are characteristic of papillary thyroid carcinoma, serous ovarian cystadenocarcinoma, meningiomas, and some types of squamous cell carcinomas. They form due to the accumulation of calcium ions in the tumor cells, which eventually leads to calcification. This process is thought to be mediated by the presence of apatite crystals, which are deposited in a concentric, lamellated pattern.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as psammoma bodies are indeed found in serous ovarian cystadenocarcinoma, making it an incorrect choice for the question.
**Option B:** This option is incorrect as psammoma bodies are characteristic of papillary thyroid carcinoma, making it an incorrect choice for the question.
**Option D:** This option is incorrect as psammoma bodies are found in some types of squamous cell carcinomas, making it an incorrect choice for the question.

**Clinical Pearl / High-Yield Fact**
Psammoma bodies can be a useful diagnostic feature in histopathology, but they should be considered in conjunction with other clinical and pathological findings. The presence of psammoma bodies can help to narrow the differential diagnosis and guide further investigation.

**Correct Answer:** A.