There are different types of fibroid. The main types of fibroids are: intramural – the most common type of fibroid, these develop in the muscular wall of the womb subserosal – fibroids that develop on the outside part of the wall of the womb and can become very large submucosal – fibroids that develop in the muscular layer of the womb beneath the womb's inner lining (endometrium) and grow into the inside of the womb pedunculated – subserosal or submucosal fibroids that are attached to the womb with a narrow stalk of tissue