Guest Author - Denise Howard, M.D., M.P.H.

Fibroids or Leiomyomata are smooth muscle tumors that are typically benign and are commonly found in the uterus. They can be present for many years before they are identified due to their slow growth. There can be one or many and they can sometimes cause the uterus to grow to the size of a term pregnancy. The most common symptoms include heavy long periods or pelvic pressure from the bulk of the uterus.

The etiology of these tumors is currently being studied and recent advances in genetic research have allowed some understanding of the cause of these tumors. The fact that they are more common in first degree relatives of women with fibroids and that the prevalence is much higher in black women suggest a genetic cause.

All the cells in our body typically have the same chromosomes. Sometimes an insult can occur causing the chromosomes in certain cells to become abnormal. Studies of fibroids have shown that 60% of the cells have normal chromosomes and 40% have abnormal chromosomes. When the abnormal chromosomes are examined in greater detail certain patterns of gene abnormalities are found. This suggest that there maybe many different gene abnormalities that results in fibroid tumors.

Why is this relevant? There is an association between the sizes of the tumors and their chromosomal make up (karotype). There is also an association between recurrence of fibroids and the karotype of the tumors. The genetic makeup of the tumor may also be helpful in predicting which of these tumors will develop into cancer.

Finally there is a rare but life threatening syndrome called Hereditary leiomyomatosis and renal cell carcinoma. Affected individuals will have smooth muscle tumors that form under their skin (cutaneous), uterine fibroids and an increased risk of malignant tumors. The malignancy involves the kidney (renal cell carcinoma) and present with large tumors of the kidney that has usually metastasized by the time it is diagnosed. These women are also at high risk of leiomyosarcoma which is a malignant fibroid tumor. If these malignancies occur as a part of this syndrome they tend to affect younger women. Thus it is important to know your family history and report this to your Gynecologist if there is a history of cutaneous fibroids, malignant fibroids and kidney cancer