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

• Esophageal Mucoepidermoid Carcinoma
• Oesophageal Mucoepidermoid Carcinoma
• Primary MEC of Esophagus

What is Primary Mucoepidermoid Carcinoma of Esophagus? (Definition/Background Information)

• Primary Mucoepidermoid Carcinoma (MEC) of Esophagus is a very rare malignant tumor of the epithelium. The esophagus is a part of the upper gastrointestinal tract and is also known as the ‘food-pipe’. The tumor is diagnosed based on examination of a biopsy specimen under the microscope by a pathologist
• In order for the tumor to be diagnosed as “primary” (i.e., Primary Mucoepidermoid Carcinoma of Esophagus), metastatic mucoepidermoid carcinoma from other sites, such as the salivary glands, tear glands, and lungs have to be ruled out. This is because Primary MEC of Esophagus is a very uncommon cancer
• The risk factors for Primary Mucoepidermoid Carcinoma of Esophagus include smoking and alcohol consumption, dietary habits that exclude fresh fruits and vegetables, and certain genetic conditions. The cause of the condition is reportedly due to various genetic abnormalities
• Superficial tumors may be painless and asymptomatic, while advanced cases present swallowing difficulties and chest and upper abdominal pain. Most Esophageal Mucoepidermoid Carcinomas are known to be misdiagnosed, due to its rarity
• The treatment of choice is a surgical excision with clear margins followed by radiation therapy/chemotherapy. In case of spread of cancer to other regions, a combination of treatments may be considered by the healthcare provider
• The prognosis depends upon a set of several factors including the stage of the tumor, extent of tumor spread, overall health of the patient, and many other factors. In general, the prognosis of Primary Mucoepidermoid Carcinoma of Esophagus is poor

Who gets Primary Mucoepidermoid Carcinoma of Esophagus? (Age and Sex Distribution)

• Primary Mucoepidermoid Carcinoma of Esophagus is observed in middle-aged and older adults
• Both males and females are affected, though the condition is much more common in males. The male-female ratio is about 3:1
• All races and ethnic groups are at risk for the condition. However, the geographical distribution may vary widely

What are the Risk Factors for Primary Mucoepidermoid Carcinoma of Esophagus? (Predisposing Factors)

The risk factors for Primary Mucoepidermoid Carcinoma of Esophagus include the following: (a combination of factors may be present in some individuals)

• Presence of certain precursor lesions
• Smoking and chewing tobacco is a major risk factor 
• Alcohol consumption
• Diet: Lack of fresh vegetables and fruits, fish and fresh meat, dairy products; also, a high consumption of processed meat (such as barbecued meat)
• Nutritional deficiencies that include vitamins A, B1, B2, B6, and C, and minerals zinc and molybdenum
• Radiation therapy for breast cancer (especially in women)
• Presence of certain genetic disorders

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 Primary Mucoepidermoid Carcinoma of Esophagus? (Etiology)

The exact cause of development of Primary Mucoepidermoid Carcinoma of Esophagus is unknown, but it may be due to certain genetic defects and gene mutations

In general, it is known that cancers form when normal, healthy cells begin transforming into abnormal cells - these cancer cells grow and divide uncontrollably (and lose their ability to die), resulting in the formation of a mass or a tumor.

• Many cancer types are caused by genetic mutations. These can occur, due to inherited mutations, or mutations that occur due to environmental factors 
• The transformation of normally healthy cells into cancerous cells may be the result of genetic mutations. Mutations allow the cancer cells to grow and multiply uncontrollably to form new cancer cells
• These tumors can invade nearby tissues and adjoining body organs, and even metastasize and spread to other regions of the body

What are the Signs and Symptoms of Primary Mucoepidermoid Carcinoma of Esophagus?

Primary Mucoepidermoid Carcinoma of Esophagus may present the following signs and symptoms:

• Initial superficial tumor may be asymptomatic; most tumors are small during diagnosis
• Commonly observed symptoms for advanced cancer are swallowing difficulties, chest pain (retrosternal pain), upper abdominal pain (epigastric pain), narrowing of esophagus can cause regurgitation or vomiting sensation
• Advanced tumors invade into the esophageal wall beyond the submucosal surface. Early stage is stage 0, when only the mucosal surfaces are involved (and may be the submucosal surfaces too)
• Site of the tumor: Most cases are observed in the thoracic region
• Esophageal carcinomas spread up and down the food-pipe or around the GI tube
• Bleeding and ulceration may be noted
• Large tumors may cause a pressure effect by compressing adjoining structures and organs
• Large tumors may ulcerate and bleed and become painful
• Involvement of lymph nodes

The symptoms of the carcinoma are reportedly similar to squamous cell carcinoma of the esophagus.

How is Primary Mucoepidermoid Carcinoma of Esophagus Diagnosed?

A diagnosis of Primary Mucoepidermoid Carcinoma of Esophagus may involve the following:

• A thorough medical history and physical examination
• X-ray of the chest
• CT or MRI scan of the chest: For advanced cases and to check cancer growth and spread, including lymph node involvement
• Upper GI endoscopy: An endoscopic procedure is performed using an instrument called an endoscope, which consists of a thin tube and a camera. Using this technique, the radiologist can have a thorough examination of the insides of the upper gastrointestinal tract
• Endoscopic ultrasonography: During this procedure, fine needle aspiration biopsy (FNAB) can be performed on the affected area. This is good technique for tumor detection including tumor invasion parameters, and whether nearby lymph nodes are affected
• Endocytoscopy: It is a non-invasive technique helpful for invasive carcinomas that are located superficially
• Early cancer lesions may be detected using narrow band imaging technique
• Barium swallow
• Whole body PET scans to determine how far the cancer has spread to other organ systems

Although the above modalities can be used to make an initial diagnosis, a tissue biopsy of the tumor is necessary to make a definitive diagnosis to begin treatment. The tissue for diagnosis can be procured in multiple different ways which include: 

• Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor and the tumor may be misdiagnosed. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
• Core biopsy of the tumor 
• Open biopsy of the tumor

Tissue biopsy:

• A tissue 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, and very rarely, electron microscopic studies to assist in the diagnosis

Note: It is very difficult to diagnose Primary Mucoepidermoid Carcinoma of Esophagus. Since these are extremely uncommon, these tumors are frequently known to be misdiagnosed.

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 Primary Mucoepidermoid Carcinoma of Esophagus?

The complications of Primary Mucoepidermoid Carcinoma of Esophagus may include the following:

• Ulceration of the tumor can lead to secondary infections of bacteria and fungus
• Compression of the underlying nerve, which can affect nerve function
• Severe obstruction of the food-pipe with pain, leading to difficulties in eating. This can lead to extreme weight loss due to malnutrition
• Perforation or rupture of the esophagus can lead to the fistula
• Stricture formation of esophagus
• Vocal cord paralysis
• Lung infection leading to pneumonia
• The tumor can metastasize to the lymph nodes and to distant organs
• Recurrence of the tumor following treatment
• Side effects of chemotherapy (such as toxicity) and radiation
• Damage to the muscles, vital nerves, and blood vessels, during surgery
• Post-surgical infection at the wound site is a potential complication

How is Primary Mucoepidermoid Carcinoma of Esophagus Treated?

The treatment of Primary Mucoepidermoid Carcinoma of Esophagus usually involves surgery, which is the first treatment option considered. It also includes a combination of radiation therapy and chemotherapy.

• When the tumor is confined to the surface, then endoscopic mucosal/submucosal resection (or surgical removal via endoscopy) is undertaken
• Esophagectomy or surgery to remove part (or all) of esophagus
• If the tumor has metastasized, then a combination of chemotherapy, radiation therapy, and invasive procedures may be used to treat the tumor
• Palliative care is provided for advanced cancer stages
• Follow-up care with regular screening and check-ups are very important and encouraged

Clinical trials: In advanced stages of cancer progression, there may be some newer treatment options currently on clinical trials, which can be considered for some patients depending on their respective risk factors.

How can Primary Mucoepidermoid Carcinoma of Esophagus be Prevented?

Currently, there are no known methods to prevent Esophageal Primary Mucoepidermoid Carcinoma occurrence. However, the risk for the condition may be lowered through the following consideration:

• Avoidance of smoking tobacco and alcohol consumption
• Consuming a diet that is rich in whole grains, vegetables, and fruits
• Correcting any nutritional imbalances through adequate vitamin and mineral supplementation
• Taking foods rich in vitamin D and calcium
• Physical activities and regular exercising
• Taking early and appropriate treatment for any gastrointestinal conditions
• If the carcinoma is associated with a genetic disorder, then genetic counseling and testing may be performed
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• In order to avoid a relapse, or be prepared for a recurrence, the entire diagnosis, treatment process, drugs administered, etc. should be well-documented and follow-up measures initiated

Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory, due to its metastasizing potential and possibility of recurrence. Often several years of active vigilance is necessary.

What is the Prognosis of Primary Mucoepidermoid Carcinoma of Esophagus? (Outcomes/Resolutions)

• The prognosis of Primary Mucoepidermoid Carcinoma of Esophagus is generally better than other esophageal carcinoma types when it is ‘purely’ mucoepidermoid
• Otherwise, the prognosis is reportedly poor in mixed mucoepidermoid carcinomas in which the combined features of mucoepidermoid carcinoma and other carcinoma types. Also, tumors that have metastasized to the lymph nodes have a poor prognosis
• The prognosis depends upon a set of several factors, which 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
  • Overall health of the individual: Individuals who have anemia (decreased hemoglobin) and significant weight loss have poorer prognosis compared those who do not have anemia (normal hemoglobin in blood) and no significant weight loss
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Individuals with bulky disease may have a poorer prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical resectability of the tumor (meaning, if the tumor can be removed completely) is a very important independent prognostic factor
  • 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: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment; good response to treatment (surgery and/or chemotherapy/radiation therapy)
  • 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
• The combination chemotherapy drugs used, may have some severe side effects (such as cardio-toxicity). This chiefly impacts the elderly adults, or those who are already affected by other medical conditions. Tolerance to the chemotherapy sessions is a positive influencing factor

Additional and Relevant Useful Information for Primary Mucoepidermoid Carcinoma of Esophagus:

The following DoveMed website links are useful resources for additional information:

http://www.dovemed.com/diseases-conditions/cancer/