What are fibroids primarily composed of?

Fibroids, also known as uterine leiomyomas, are primarily composed of smooth muscle tissue along with fibrous connective tissue. These benign tumors arise from the myometrium, which is the middle layer of the uterine wall. The smooth muscle cells in fibroids can undergo hypertrophy and hyperplasia, leading to the growth of these tumors. The fibrous component contributes to the structure and firmness of the fibroid.

While adipose tissue is involved in different types of growths and can be found in the body, fibroids specifically do not arise from fat cells. Similarly, although fibroids contain connective tissue, it is not accurate to say they are composed solely of connective tissue; smooth muscle is a key component as well. Excessive vascular tissue is not characteristic of fibroids, as their composition is primarily muscular and fibrous instead of vascular. Therefore, the understanding that fibroids consist predominantly of muscle and fibrous tissue is fundamental to identifying their nature and characteristics.