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

• Malignant Myoepithelial Tumour of Lung
• Pulmonary Myoepithelial Carcinoma
• Salivary Gland Myoepithelial Cancer of Lung

What is Myoepithelial Carcinoma of Lung? (Definition/Background Information)

• Myoepithelial tumors of the lung are extremely rare tumors that may be benign or malignant. The benign tumors are known as myoepitheliomas of the lung
• Myoepithelial Carcinoma of Lung is a malignancy of the lung, which can occur either in the lung tissue or within the bronchial airways
• These lung tumors are mostly observed in adults. The exact cause of Myoepithelial Carcinoma of Lung is unknown, and presently, no specific risk factors have been identified
• Small-sized Myoepithelial Carcinoma of Lung in the peripheral lung region may be asymptomatic. The tumors affecting the bronchus/airways may present coughing, chest pain, and breathing difficulties
• The treatment of Pulmonary Myoepithelial Carcinoma is undertaken through surgery. However, since it may be difficult to remove the entire tumor, chemotherapy and/or radiation therapy may be necessary
• The prognosis of Myoepithelial Carcinoma of Lung is generally guarded, since it is known to be locally invasive and metastasis to various body sites can occur. Tumor metastasis is known to occur to the liver and brain

Who gets Myoepithelial Carcinoma of Lung? (Age and Sex Distribution)

• Myoepithelial Carcinoma of Lung is a very rare tumor; less than 15 cases of both benign and malignant myoepithelial tumors have been recorded
• Most of the cases are observed in adults
• A very high preference for males is noted, though both males and females are affected
• There is no racial or ethnic group predilection observed

What are the Risk Factors for Myoepithelial Carcinoma of Lung? (Predisposing Factors)

• Currently, no risk factors have been identified for the formation of Myoepithelial Carcinoma of Lung

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones 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 Myoepithelial Carcinoma of Lung? (Etiology)

The cause of development of Myoepithelial Carcinoma of Lung is generally unknown.

• It may be caused by certain genetic abnormalities; rearrangement of the EWSR1 gene has been observed in these tumors
• Some carcinomas have shown abnormalities involving the EWSR1-ZNF444 and FUS genes
• Research is currently being undertaken to identify the relevant causal factors

What are the Signs and Symptoms of Myoepithelial Carcinoma of Lung?

Myoepithelial Carcinoma of Lung can arise in the following lung parts:

• Within the bronchial airways, as an endobronchial mass in the central region of the lungs
• In the peripheral lung region, as a nodule

Small-sized Pulmonary Myoepithelial Carcinoma tumors (including those in the lung periphery) may present no clinical indications and remain asymptomatic. The following features may be observed in other cases:

• The tumors range in size from 1.5-13 cm; some carcinomas are known to grow to larger sizes
• An invasive growth pattern may be present and some show haemorrhaging; necrosis of the tumor mass may also be observed
• Tumors arising in the airways can cause obstructive symptoms including chest pain, shortness of breath, and cough
• Advanced stage tumors may present weight loss and fatigue

How is Myoepithelial Carcinoma of Lung Diagnosed?

There are a variety of tests the healthcare provider may employ to detect and diagnose Myoepithelial Carcinoma of Lung. These may include:

• Physical examination and complete medical history screening: During the physical exam, the healthcare provider may listen to the chest using a stethoscope, to look for the presence of any abnormal lung sounds
• Imaging studies that may include a chest X-ray, MRI scan or CT scan of the lungs
• 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. Even though this procedure may be performed, no tumor cells are generally noted

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 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

Tissue biopsy from the affected lung:

• A biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist 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. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, flow cytometric analysis and very rarely, electron microscopic studies, to assist in the diagnosis

A differential diagnosis with respect to other lung cancer types may be necessary prior to establishing a definite diagnosis, by excluding the following cancers:

• Epithelial-myoepithelial lung carcinoma
• Other salivary gland tumors of the lung, or those that have metastasized to the lung
• Non-small cell carcinomas including large cell and basaloid squamous cell carcinomas

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 Myoepithelial Carcinoma of Lung?

Complications associated with Myoepithelial Carcinoma of Lung may include:

• Severe obstruction of the airways, in case of a large-sized tumor
• Large tumors can compress the heart and impede its function
• Some tumors may cause severe chest pain
• Spread/metastasis of the tumor to other parts of the lung, liver, brain, and soft tissues
• Recurrence may occur, if the tumor is removed incompletely

There may be complications related to the methods used in treating the condition and may include:

• Side effects of radiation therapy that may include sunburn-like rashes, where radiation was targeted, red or dry skin, heaviness of the breasts, and general fatigue
• Side effects of chemotherapy, which may include nausea, vomiting, hair loss, decreased appetite, mouth sores, fatigue, low blood cell counts, and a higher chance of developing infections
• The treatment can also cause infertility in men and women. Hence, measures to protect the individual’s fertility must be considered, before starting chemotherapy

How is Myoepithelial Carcinoma of Lung Treated?

The treatment of Myoepithelial Carcinoma of Lung may involve the following:

• Surgery: Complete excision where possible is attempted; though, it may be difficult for the lung tumor to be removed completely
• Radiation therapy and/or chemotherapy may be necessary to aid in the treatment
• Embolization (clotting the vessels in the tumor) may be used to provide temporary relief from the symptoms and reduce blood loss during a surgical procedure
• Follow-up care with regular screening and check-ups are important and encouraged

How can Myoepithelial Carcinoma of Lung be Prevented?

• Currently, there are no known methods to prevent the development of Myoepithelial Carcinoma of Lung
• Due to its metastasizing potential and recurrence, regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory for those who have already been treated for this tumor

What is the Prognosis of Myoepithelial Carcinoma of Lung? (Outcomes/Resolutions)

• The prognosis for Myoepithelial Carcinoma of Lung is generally guarded. Due to its extreme rarity, accurate prognostic parameters/values are not currently available
• However, positive outcomes may be influenced by a lower cell division rate and diagnosis of early stage cancers
• The prognosis of lung cancer, in general, depends upon a set of several factors that include:
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • The size of the lung tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • Individuals with bulky disease of the lung cancer have a poorer prognosis
  • Involvement of the lymph node, which can adversely affect the prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical respectability of the tumor (meaning, if the tumor can be removed completely)
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Response to treatment of lung cancer: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
  • Progression of the condition makes the outcome worse
• An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment

Additional and Relevant Useful Information for Myoepithelial Carcinoma of Lung:

The following article link will help you understand other lung conditions:

http://www.dovemed.com/healthy-living/healthy-lungs/