**Question:** An ovarian neoplasm in a 15-year-old girl is most likely to be

A. Brenner tumor
B. Brenner tumor (a rare variant)
C. Brenner tumor (most common tumor in older females)
D. Germ cell tumor

**Core Concept:**
Ovarian neoplasms in pediatric patients are often different from those in adults. In girls and young women, the most common ovarian tumor is a germ cell tumor, which arises from immature germ cells. Brenner tumors, on the other hand, are more common in older females and rarely occur in teenagers.

**Why the Correct Answer is Right:**
In the case of a 15-year-old girl, the correct answer is D (Germ cell tumor) because germ cell tumors are the most common type of ovarian neoplasm in pediatric patients. Germ cell tumors can be further categorized into two main types: dysgerminomas and non-dysgerminomas.

**Why Each Wrong Option is Incorrect:**
A: Brenner tumor is a rare variant of ovarian neoplasm in pediatric patients. Although it is more common in older females, it is not the most likely diagnosis in a 15-year-old girl.
B: Brenner tumor is a rare variant of ovarian neoplasm, not a common tumor in pediatric patients.
C: Brenner tumor is the most common tumor in older females, not 15-year-old girls.

**Clinical Pearl:**
Ovarian neoplasms in pediatric patients should be considered in the differential diagnosis when evaluating a girl or young woman with a pelvic mass. This is crucial for accurate diagnosis and appropriate treatment planning.

**Correct Answer:** D (Germ cell tumor)