Psammoma bodies may be seen in all of the following, except
**Core Concept**
Psammoma bodies are laminated calcifications that are often seen in certain types of tumors, particularly papillary thyroid carcinoma, serous ovarian cystadenocarcinoma, and meningioma. They are formed as a result of the deposition of calcium phosphate in the tumor cells.
**Why the Correct Answer is Right**
Psammoma bodies are characteristic of papillary thyroid carcinoma, where they are found in 40-70% of cases. They are formed due to the accumulation of calcium in the tumor cells, which is thought to be related to the expression of certain genes, such as the BRAF V600E mutation. The presence of psammoma bodies can be a useful diagnostic feature, particularly in fine-needle aspiration biopsies.
**Why Each Wrong Option is Incorrect**
**Option A:** Psammoma bodies may be seen in meningiomas, which are typically benign tumors arising from the meninges. This option is incorrect because while psammoma bodies can be seen in meningiomas, they are not specific to this tumor type.
**Option B:** Psammoma bodies are not typically seen in renal cell carcinoma, which is a type of kidney cancer. However, some variants of renal cell carcinoma, such as papillary renal cell carcinoma, may exhibit psammoma bodies.
**Option C:** Psammoma bodies are not typically seen in hepatocellular carcinoma, which is a type of liver cancer. While calcifications can be seen in hepatocellular carcinoma, they are not usually in the form of psammoma bodies.
**Clinical Pearl / High-Yield Fact**
Psammoma bodies are a classic example of a "tumor marker" that can be used to support a diagnosis of papillary thyroid carcinoma. However, they are not specific to this tumor type and can be seen in other conditions, such as meningiomas.
**Correct Answer:** D.