What are the other Names for this Condition? (Also known as/Synonyms)

• BML of Lung
• PBML (Pulmonary Benign Metastasizing Leiomyoma)
• Pulmonary Benign Metastasizing Leiomyoma (PBML)

What is Benign Metastasizing Leiomyoma of Lung? (Definition/Background Information)

• Benign metastasizing leiomyoma (BML) is a rare tumor generally observed in middle-aged and older women. It almost only occurs in women against a background of uterine fibroids (uterine leiomyoma), a history of surgery to remove the fibroids, or post-hysterectomy (following surgical removal of the uterus)
• A benign metastasizing leiomyoma can be observed at various body sites including the breasts, gastrointestinal tract, peritoneum, abdomen, heart, windpipe (trachea), muscles of the arms/legs, lymph nodes of the abdomen and para-aortic region, central nervous system (CNS), and the skin. However, the most common site of BML is the lung
• Benign Metastasizing Leiomyoma of Lung is characterized by the presence of scattered nodules in the lung. And, even though it is called ‘metastasizing’, these tumors are non-malignant. A leiomyoma is a benign smooth muscle tumor that can develop anywhere in the body
• The tumors are generally painless and do not show any signs and symptoms in many cases. Some women may have chest pain, shortness of breath, and coughing. Large tumors in the lungs can cause obstructive signs and symptoms due to compression of adjoining organ structures including blood in sputum and breathing difficulties
• The treatment of choice for Benign Metastasizing Leiomyoma of Lung is a surgical removal of the entire tumor(s). Generally, the prognosis is good with early diagnosis and appropriate treatment

Who gets Benign Metastasizing Leiomyoma of Lung? (Age and Sex Distribution)

• Benign Metastasizing Leiomyoma of Lung may affect females of any age, but is mostly present in the 30-75 year’ age range (occurring in pre-, peri- and post- menopausal women)
• In women with a history of hysterectomy, the tumor may form from anywhere between 3 months to 20 years after the surgery
• There is no geographical, racial, or ethnic preference noticed
• The tumor is very rare and only about 100 cases have been recorded in the medical literature

What are the Risk Factors for Benign Metastasizing Leiomyoma of Lung? (Predisposing Factors)

The risk factors for Benign Metastasizing Leiomyoma of Lung may include:

• Women with a history of surgery - either a myomectomy (for removal of uterine fibroids) or a hysterectomy (uterus removal)
• Presence of uterine fibroids or leiomyomas
• Late childbearing history in women
• Imbalance of estrogen and progesterone hormone levels in the body

In general, the risk factors for leiomyoma of uterine corpus (or uterine fibroids), which is an associated condition, may include the following:

• Family history of the condition
• Women of African descent are at a higher risk in comparison to individuals of other races/ethnic groups
• Early onset of menstruation (in girls)
• Obesity, being overweight
• High in meat and low in vegetables diet
• Vitamin D deficiency
• Excessive alcohol consumption

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Benign Metastasizing Leiomyoma of Lung? (Etiology)

The exact cause of Benign Metastasizing Leiomyoma of Lung development is unknown. Nevertheless, the following theories have been proposed to explain/understand these tumors:

• Some researchers believe that like endometriosis (which is not only confined to the uterus, but also found away from the primary site), benign metastasizing leiomyomas spread to distant sites through the vascular system - a process known as leiomyomatosis
• BML is related to low-grade leiomyosarcomas, which are malignant smooth muscle tumors. However, it is important to recognize that BML tumors are benign
• Pulmonary BML represents smooth muscle spread to sites outside the uterus (multifocal spread); however, this proposal is currently being refuted

The following chromosomal anomalies specific to BML have been observed:

• Terminal deletion of the long arm of chromosome 19 (19q)
• Terminal deletion of the long arm of chromosome 22 (22q)

A majority of the leiomyomas are considered to be benign. Some researchers consider them as borderline tumors and term them as having uncertain malignant potential.

What are the Signs and Symptoms of Benign Metastasizing Leiomyoma of Lung?

A majority of women do not show any signs and symptoms. In others, the signs and symptoms of Benign Metastasizing Leiomyoma of Lung may include:

• Breathing difficulties, shortness of breath
• Dry cough and sometimes, blood in cough, may be noted
• Chest pain
• The presence of multiple, scattered lung lesions in the form of nodules
• The tumors may be well-circumscribed with defined borders
• The pulmonary tumors may involve the bronchus/alveoli
• The tumor size depends on hormonal factors - estrogen increases the tumor size, while progesterone shrinks the tumor
• Factors such as pregnancy and menopause are known to affect the size of BML (tumor size decreases)
• In some individuals, fever and stuffiness of chest may be present
• In 70% of the cases, both lungs are involved and multiple tumors are observed
• 1 in 5 individuals may have one lung being involved; 1 in 6 may present with only a single tumor in the lung
• Following lung, the lymph nodes are the most common sites for these tumors. Mostly the pelvic lymph nodes and the para-aortic lymph nodes are affected
• Other locations of the metastatic tumor component may include the base of the skull, spine, heart, bone, and limb muscles

The signs and symptoms of BML of uterus may include the following:

• Many women may have pain in the pelvic region, heavy bleeding during menstruation, and signs and symptoms occurring due to tumor compression
• Women, who are pregnant or under progesterone therapy, may have abdominal pain, discomfort, and other abdomen-related signs and symptoms
• Large tumors may cause a feeling of fullness in the abdomen
• Enlargement of lower abdomen
• Frequent urination due to compression/pressure of the tumor
• Lower back pain
• Pain during sexual intercourse
• Bleeding can occur within large tumors (termed as intraleiomyoma hemorrhage)
• Hemorrhage within the tumors can lead to tissue death (or infarction of leiomyoma)
• The bleeding or tissue death within the tumor can also occur during treatment with hormones such as progesterone

How is Benign Metastasizing Leiomyoma of Lung Diagnosed?

The diagnosis of Benign Metastasizing Leiomyoma of Lung may involve the following tests and procedures:

• Complete physical examination with thorough evaluation of medical history
• Pulmonary function tests can help determine the extent of lung damage; it can also help the healthcare provider assess the ability of lungs to deliver oxygen to the body
• Chest X-ray: Two-dimensional pictures using tiny amounts of radiation are taken to detect any tumors or other medical issues associated with the lungs, such as pneumonia
• Computerized tomography (CT) scan: Also known as CAT scan, this radiological procedure creates detailed three-dimensional images of structures inside the body
• Magnetic resonance imaging (MRI) scan: An MRI scan uses magnetic fields that create high quality pictures of certain body parts, such as tissues, muscles, nerves, and bones. These high-quality images may indicate to a physician, if any tumor is present
• Blood tests that include:
  • Complete blood count (CBC) to detect the cause of anemia
  • Determination of estrogen/progesterone levels in blood
  • Arterial blood gases
  • Lung function test (pulmonary function test)
• Sputum cytology: This procedure involves the collection of mucus (sputum), coughed-up by a patient, which is then examined in a laboratory by a pathologist
• Additionally, abdominal/pelvic imaging studies to detect uterine fibroids may be recommended
• Hysteroscopy: This procedure involves placing a probe through the cervix to examine the cavity of the uterus. This exam is helpful in detecting submucosal leiomyomas
• Hysterosalpingography: It is usually performed in individuals with infertility. In this procedure, the structure of the uterus and fallopian tubes are studied by using a dye and X-ray images
• Needle biopsy of tumor: A needle biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a needle biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
• Open biopsy of tumor: A tissue biopsy is performed and sent to a laboratory for a pathological examination, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis
• Differential diagnosis, to eliminate other tumor types is considered, before arriving at a definitive diagnosis

A tissue biopsy refers to a medical procedure that involves the removal of cells or tissues, which are then examined by a pathologist. This can help establish a definitive diagnosis. The different biopsy procedures (for lung) may include:

• Bronchoscopy: During bronchoscopy, a special medical instrument called a bronchoscope is inserted through the nose and into the lungs to collect small tissue samples. These samples are then examined by a pathologist, after the tissues are processed, in an anatomic pathology laboratory
• Thoracoscopy: During thoracoscopy, a surgical scalpel is used to make very tiny incisions into the chest wall. A medical instrument called a thoracoscope is then inserted into the chest, in order to examine and remove tissue from the chest wall, which are then examined further
• Thoracotomy: Thoracotomy is a surgical invasive procedure with special medical instruments to open-up the chest. This allows a physician to remove tissue from the chest wall or the surrounding lymph nodes of the lungs. A pathologist will then examine these samples under a microscope after processing the tissue in a laboratory
• Fine needle aspiration biopsy (FNAB): During fine needle aspiration biopsy, a device called a cannula is used to extract tissue or fluid from the lungs, or surrounding lymph nodes. These are then examined in an anatomic pathology laboratory, in order to determine any signs of abnormality
• Autofluorescence bronchoscopy: It is a bronchoscopic procedure in which a bronchoscope is inserted through the nose and into the lungs and measure light from abnormal precancerous tissue. Samples are collected for further examination by a pathologist

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Benign Metastasizing Leiomyoma of Lung?

The possible complications of Benign Metastasizing Leiomyoma of Lung include:

• Obstruction of the airways in case of a large-sized tumor in the lung; this may result in a severe respiratory failure
• Large tumors of the lung may also compress the heart and impede its function
• Some lung tumors may cause severe chest pain
• Apart from the lung, there may be associated tumors at other body sites too
• Complications due to tumors in the uterus including infertility, cervical prolapse, etc.
• Recurrence of the tumor due to its partial or incomplete surgical removal

How is Benign Metastasizing Leiomyoma of Lung Treated?

The treatment of Benign Metastasizing Leiomyoma of Lung may include:

• Surgical removal of the lung tumor(s)
• Stabilization of the tumors through hormone therapy (often long-term); controlling estrogen levels
• Inferior vena cava (IVC) filter placement: Preventing embolism to the lung by placement of IVC filter
• Medical treatment options:
  • Pain medications for fibroids causing pain
  • Dietary and lifestyle modification to address overweight issues
  • Address vitamin deficiencies in the body
• Surgical treatment options for fibroids:
  • Myomectomy: Removal of the fibroids (also known as fibroidectomy)
  • Hysterectomy: The removal of a part of the uterus or the entire uterus - for women who have completed their family
  • Myolysis: In this procedure, a needle is inserted into the tumor/fibroid. After the insertion, the fibroid is destroyed either by using an electric current, or by a freezing technique
  • Radiofrequency ablation: In this technique, the tumors are destroyed using radio waves
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Close follow-up after surgery and long-term checkup with regular screening is advised

How can Benign Metastasizing Leiomyoma of Lung be Prevented?

Current medical research has not established a method of preventing Benign Metastasizing Leiomyoma of Lung. However, the following general factors may be considered to reduce the risk for tumor development:

• Address any condition causing hormonal imbalance in the body
• Maintain weight through proper diet modification and physical exercises, if you are overweight/obese
• Avoid alcohol consumption or limit its intake
• Have a balanced diet that is not high in meat and low in vegetables; a balanced diet can also help avoid any mineral or vitamin deficiencies in the body

Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations are mandatory, due to risk of recurrence of the tumor. Often several years of active vigilance is necessary.

What is the Prognosis of Benign Metastasizing Leiomyoma of Lung? (Outcomes/Resolutions)

• The prognosis of Benign Metastasizing Leiomyoma of Lung generally depends on early diagnosis and appropriate treatment, including a surgical excision and removal of the tumor
• The prognosis of the condition can be highly-variable; sometimes, the tumors in the lung are known to result in respiratory failure and death

Additional and Relevant Useful Information for Benign Metastasizing Leiomyoma of Lung:

• Fibroid tumor removal (or myomectomy) is the surgical removal of fibroids from the uterus

The following link will help you understand fibroid tumor removal surgical procedure:

http://www.dovemed.com/common-procedures/procedures-surgical/fibroid-tumor-removal/

• Hysterectomy is a surgical procedure characterized by the surgical removal of the uterus

The following link will help you understand hysterectomy surgical procedure:

http://www.dovemed.com/common-procedures/procedures-surgical/hysterectomy-abdominal-with-salpingo-oophorectomy/