In a case of precocious puberty due to an ovarian tumor, the tumor is most likely derived from which cell type?

In cases of precocious puberty associated with an ovarian tumor, the tumor is most likely derived from granulosa cells. Granulosa cells are responsible for producing estrogen in the ovaries, and an increase in estrogen production can lead to the early development of secondary sexual characteristics, a hallmark of precocious puberty.

Ovarian tumors that arise from granulosa cells can cause hormonal imbalances that stimulate the growth and maturation of reproductive tissues prematurely. Such tumors, specifically granulosa cell tumors, can secrete estrogen continuously, leading to symptoms seen in precocious puberty.

While ovarian tumors can also arise from other cell types, such as stromal fibroblasts and thecal cells, these are less commonly associated with precocious puberty. Germinal epithelium typically gives rise to surface epithelial tumors, which are not usually linked to the excessive estrogen production characteristic of precocious puberty. Granulosa cell tumors directly implicate estrogen overproduction, making them the most likely source in this context.