**Core Concept**
Call-Exner bodies are histopathological features that represent rosettes of granulosa cells surrounding a central space, often containing eosinophilic fluid. This characteristic histological finding is a diagnostic hallmark of a specific type of ovarian tumor. The presence of Call-Exner bodies is crucial for identifying granulosa cell tumors, which are sex cord-stromal neoplasms.

**Why the Correct Answer is Right**
Granulosa cell tumors arise from the sex cord-stromal tissue of the ovary and are characterized by the presence of Call-Exner bodies. These structures are formed by rosettes of granulosa cells surrounding a central space, often containing eosinophilic fluid. This distinctive histological feature is a result of the tumor cells' ability to form rosettes, which is a characteristic of granulosa cell tumors. The formation of Call-Exner bodies is thought to be related to the tumor cells' attempt to mimic the normal ovarian follicular structure.

**Why Each Wrong Option is Incorrect**
**Option A:** Dyserminomas are a type of germ cell tumor that typically presents with a different histological appearance, characterized by sheets of anaplastic cells. They do not exhibit the characteristic Call-Exner bodies seen in granulosa cell tumors.
**Option B:** Hilus cell tumors are also sex cord-stromal tumors, but they are characterized by the presence of Leydig cells, which are different from granulosa cells. Hilus cell tumors do not exhibit Call-Exner bodies.
**Option C:** Brenner's tumors are a type of ovarian tumor that is composed of transitional-type epithelial cells. They do not exhibit the characteristic histological features of granulosa cell tumors, including Call-Exner bodies.

**Clinical Pearl / High-Yield Fact**
When diagnosing ovarian tumors, it is essential to recognize the characteristic histological features, including the presence of Call-Exner bodies in granulosa cell tumors. This can help differentiate granulosa cell tumors from other types of ovarian tumors and guide treatment decisions.

**✓ Correct Answer: D. Granulosa cell tumours**