Cyst and fibroid are commonly encountered in the outpatient and inpatient gynecological practices. Both conditions are mostly benign although some cysts can be malignant. Fibroids are always benign except in extremely rare cases of malignant transformations. Both conditions have similar presentations. They may present as a pelvic mass, dyspareunia, menstrual irregularities, and incidentally during routine investigations. A good history, examination and ultrasound scanning may be needed to differentiate between the two.
Cyst is a collection of fluid walled off due to tissue reactions. There are two types of cysts. They are true cyst and pseudo-cyst. The main defining characteristic between the two is the presence of a well formed wall in a cyst and lack of same in a pseudo-cyst. A pseudo-cyst is a collection of fluid walled off by natural surrounding tissue. Cysts can occur anywhere in the body. Ovarian cyst, pseudo-pancreatic cyst, vaginal wall cyst, and fallopian tube cyst are a few common cysts. Fluid in the cysts does not contain a high protein amount. Cysts forms because of excessive accumulation of fluid. The ovary has a lot of follicles which absorb fluid and become graafian follicles. Graafian follicle contains a fluid filled cavity. When ovulation does not occur, the follicle continues to absorb fluid, and the ovarian cyst forms. In the pancreas, when outflow ducts are blocked, secretions accumulate in the glandular parts to give rise to pancreatic cyst.
There are benign and malignant cysts. Malignant cysts form due to cancerous cells. When there are cancer cells, almost always there is excessive secretion of fluid and cysts are the end result. Malignant cysts contain multiple thick half walls inside the cavity partially dividing it into compartments. The outer wall of malignant cysts is normally very vascular. The outer wall may have irregular protrusions. Some malignant cysts secrete specific markers that can be used in the assessment. Malignant epithelial cysts in ovary secrete a chemical called CA-125. Serum CA-125 level is above 35 in malignant cysts.
Fibroid is a benign abnormal growth of smooth muscle tissue. They occur mainly in the walls of hollow viscera in the body. Uterine fibroid is a very common example. Fibroids may occur in twos or threes or as clusters. If there are too many to count, the condition is called leiomyomatosis. Fibroids may be extremely rarely cancerous. A malignant fibroid is called a leiomyosarcoma. Uterine fibroids are the commonest types of tumor in females of reproductive age. Most fibroids are asymptomatic. Large fibroids may compress surrounding structures and impair the contraction of smooth muscle tissues from which it arose.
Uterine fibroids may present as pelvic heaviness, excessive menstrual bleeding, dyspareunia, and abdominal distention. Some fibroids may cause subfertility by blocking the fallopian tubes, interfering implantation and placentation. Uterine fibroids are estrogen sensitive. They enlarge during pregnancy and undergo red degeneration. Red degenerated fibroid may cause severe abdominal pain. Small fibroids may be left alone as they regress after menopause. Pain killers are the only way to manage fibroids during pregnancy. Large fibroids may be removed via myomectomy or hysterectomy if the woman has completed her family.
What is the difference between Cyst and Fibroid?
• Cysts are fluid filled while fibroids are solid tumors.
• Cysts may arise from epithelial tissue while fibroids arise from smooth muscle tissue.
• Cysts can be cancerous while fibroids are cancerous only extremely rarely.
Difference Between Cyst and Abscess