Which of the following is not a histological feature of adamantinomatous craniopharyngioma?
**Core Concept**
Adamantinomatous craniopharyngioma is a type of brain tumor characterized by its histological features, which are essential for differential diagnosis from other craniopharyngioma subtypes. The histological features of adamantinomatous craniopharyngioma include the presence of adamantinomatous epithelium, calcification, and a characteristic "wet" keratinization pattern.
**Why the Correct Answer is Right**
Adamantinomatous craniopharyngioma is known for its adamantinomatous epithelium, which is composed of basal cells and peripheral palisading cells. The presence of calcification is another hallmark feature, often seen as psammomatous calcifications. The "wet" keratinization pattern is a result of the accumulation of keratin in the tumor cells, leading to a characteristic histological appearance. This tumor type is also associated with the presence of beta-catenin nuclear accumulation due to CTNNB1 mutations.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as adamantinomatous craniopharyngioma indeed exhibits a characteristic "wet" keratinization pattern, which is a result of the accumulation of keratin in the tumor cells.
**Option B:** This option is incorrect as adamantinomatous craniopharyngioma is characterized by the presence of calcification, which is often seen as psammomatous calcifications.
**Option C:** This option is incorrect as adamantinomatous craniopharyngioma is known for its adamantinomatous epithelium, which is composed of basal cells and peripheral palisading cells.
**Clinical Pearl / High-Yield Fact**
Adamantinomatous craniopharyngioma is the most common subtype of craniopharyngioma and is often associated with calcification, which can be visualized on imaging studies. The presence of beta-catenin nuclear accumulation due to CTNNB1 mutations is a key diagnostic feature of this tumor type.
**Correct Answer: D.**