In the context of granulosa cell tumors, what feature is most indicative of their activity?

Granulosa cell tumors are a type of sex-cord stromal tumor of the ovary that are known for their ability to produce estrogen. One of the most significant indicators of their activity is the production of estrogen, which can lead to various clinical manifestations such as abnormal uterine bleeding, signs of estrogen excess, and changes in secondary sexual characteristics due to the hormonal influence.

Estrogen production is critical because it serves as a useful marker for the tumor's functional status. Patients with granulosa cell tumors often exhibit elevated levels of estrogen in the serum, which is consistent with the tumor's origin from granulosa cells that normally participate in the synthesis of estrogen during follicle maturation.

While other hormones like androgens and progesterone may be produced by different cells or tumors, granulosa cell tumors are more specifically characterized by their ability to produce estrogen. Therefore, recognizing estrogen levels as an indicator of activity in granulosa cell tumors is essential for diagnosis and management. The clinical implications of this activity highlight the importance of monitoring for estrogen-related symptoms in patients diagnosed with this type of tumor.