A 5-year-old girl begins developing secondary sexual characteristics, including pubic hair growth and breast development. Her concerned parents bring her to the pediatrician for evaluation. An abdominal ultrasound examination reveals an ovarian mass. The mass is resected and pathologic examination reveals it to be a granulosa cell tumor. Which of the following histologic findings is a characteristic of this type of ovarian tumor?

**Core Concept**
Granulosa cell tumors are a type of sex cord-stromal tumor that arises from the ovarian stroma, specifically from the granulosa cells. These tumors are known for their potential to produce estrogen, leading to precocious puberty in young girls.

**Why the Correct Answer is Right**
The characteristic histologic finding of granulosa cell tumors is the presence of **Call-Exner bodies**. These are small, round, or ovoid structures composed of a central rosette of granulosa cells surrounded by a basement membrane and often a halo of eosinophilic material. The presence of Call-Exner bodies is a diagnostic hallmark of granulosa cell tumors. The estrogen produced by these tumors can lead to precocious puberty, as seen in this 5-year-old girl.

**Why Each Wrong Option is Incorrect**
**Option A:** The presence of **Hilus cells** is a characteristic feature of Sertoli-Leydig cell tumors, not granulosa cell tumors.
**Option B:** **Fibrosarcoma** is a type of malignant tumor that arises from fibroblasts, and it is not associated with granulosa cell tumors.
**Option C:** **Theca cell tumors** are a type of sex cord-stromal tumor, but they are not characterized by Call-Exner bodies.

**Clinical Pearl / High-Yield Fact**
Granulosa cell tumors can produce estrogen, leading to precocious puberty in young girls. A high index of suspicion should be maintained for these tumors in cases of precocious puberty, especially in the presence of an ovarian mass.

**Correct Answer:** C. Call-Exner bodies.

✓ Correct Answer: B. Call-Exner bodies