Are Leiomyomas Cancerous?

Leiomyomas are also known as fibroids or myomas. They are the most common type of benign smooth muscle cell tumors. Their propensity to become cancerous is very rare, less than 1%. Although, leiomyomas can be found anywhere in the body, they are most commonly found in the uterus, esophagus and small intestine. The other sites where they can be found are retroperitoneum, stomach, gallbladder, skin, nipple and areola. They should not be confused with leiomyosarcoma, as these leiomyomas are non-cancerous tumors whereas leiomyosarcomas are malignant cancers.

Leiomyomas are the most common benign tumors found in the female reproductive system. They are made up of smooth muscle cells and fibrous connective tissue. It is estimated that about 20-50% women of childbearing age have fibroids, some of which go undetected due to their smaller size. The influence of estrogen has been linked to the formation of leiomyomas and menopausal women are at a greater risk of developing it. In addition, women of African-American origin are at a greater risk of developing it.

The symptoms can range from mild to severe and include heavy or prolonged menstrual bleeding, abnormal bleeding between menses, pelvic pain, low back pain, frequent urination, pain during intercourse and a firm mass can be felt near the middle of the pelvis on examination. The heavy and abnormal bleeding can also lead to iron deficiency anemia.

It can be diagnosed on routine pelvic examination and can be confirmed with an X-ray, transvaginal ultrasound, MRI, hysteroscopy, hysterosalpingography, endometrial biopsy and blood test (to detect iron deficiency anemia).

The treatment can range from observation to hysterectomy, conservative surgical therapy (myomectomy), gonadotropin-releasing hormone agonists, anti-hormonal (estrogen and progesterone), uterine artery embolization and anti-inflammatory pain relievers for pelvic pain.

Leiomyomas are commonly found in the mesenchyma of esophagus. They can be found as a solitary lesion or multiple lesions (seedling leiomyomas), although solitary lesions are more common. They occur more frequently in men than in women and usually occur in young individuals between 30 to 40 years. They are commonly found in the inner layer of muscularis propria. Most of the leiomyomas are found in the distal esophagus then in mid and proximal esophagus. The leiomyomas found in the distal esophagus are known as leiomyomatosis.

The size of esophageal leiomyoma can vary from 1-29 cm, although most of them are less than 5 cm. The most common symptoms include dysphagia, dyspepsia, esophageal reflux, cough, gastrointestinal bleeding and epigastric pain, which are non-specific.

It can be found incidentally in a radiograph and other tests include barium swallow test, CT scan and upper endoscopy. However, it can be easily confused with a mediastinal mass.

Treatment includes endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), thoracotomy or video-assisted thoracoscopy (VATS).

The most common site for leiomyoma is colorectal region where they occur 80% of the times. They are derived from smooth muscle cells of muscularis mucosae, muscularis propria or vessel related smooth muscle cells and can be either superficial or deep tumors. They are usually small and solitary lesions. They are found in this region as submucosal polyps and are rarely found in small intestine and stomach. They are commonly found in men with a male to female ratio of 2.4: 1 and usually older individuals of 55-65 years are most commonly affected.

The cause of these lesions is still unknown. Although, they are benign tumors, malignant transformation of leiomyomas is quite rare. These lesions are often asymptomatic and on rare occasions they may cause vomiting, gastrointestinal bleeding, blockage or rupture of the intestines.

They are most commonly found incidentally on upper endoscopy or colonoscopy. Histologically, they can have overlapping features with gastrointestinal stromal tumors (GIST) in FNAC (fine needle aspiration cytology) and core biopsy reports.

When asymptomatic, surgery is possibly best avoided. When symptomatic they have to be surgically excised. They can be excised endoscopically, laparoscopically or through open surgery. Laparoscopic approaches include wedge resection, intragastric resection or gastrotomy with resection.

Also Read:

• What is Leiomyomata and How is it Treated?