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Adenoid Cystic Carcinoma of Lung

Last updated March 30, 2018

Approved by: Krish Tangella MD, MBA, FCAP


Microscopic pathology image showing perineural invasion in Adenoid Cystic Carcinoma of the lung on a lung biopsy.

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

  • ACC of Lung
  • Adenocystic Carcinoma of Lung
  • Pulmonary Adenoid Cystic Carcinoma

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

  • Adenoid Cystic Carcinoma (ACC) of Lung is a very rare and unusual form of cancer. It is typically observed in middle-aged and older adults. The tumor may be present in the lung tissue or within the bronchial airways. If it is present in the bronchial airways, it is called Adenoid Cystic Carcinoma of Bronchus
  • A diagnosis of Adenoid Cystic Carcinoma of Lung is established based on a tumor biopsy and examination under a microscope by a pathologist. Because of its rarity, it is often considered to be an ‘orphan tumor’. The rarity can pose diagnostic challenges and treatment difficulties
  • The risk factors and cause of Adenoid Cystic Carcinoma of Lung are generally unknown. Genetic abnormalities have been observed in some tumors involving the MYB and NFIB genes
  • Most tumors are painless and grow very slowly on the body, but an erratic/random growth pattern may be observed; involvement of the surrounding nerves may also be noted. In many cases, during the early stages (sometimes for many years), no significant signs and symptoms are noticed
  • Depending on their size and location, the tumors may present chest pain, breathing difficulties, blood in sputum, and recurrent cough. Adenoid Cystic Carcinoma of Lung is known to metastasize to the local lymph nodes and lungs
  • The treatment of choice is a surgical excision with clear margins followed by radiation therapy. In case of spread of cancer to other regions, chemotherapy may be considered by the healthcare provider. Close follow-up is necessary for several years/decades after treatment
  • The prognosis depends upon a set of several factors including the stage of the tumor, age of the individual, the size of the tumor, and many other factors. In general, due to the unpredictable nature of Adenoid Cystic Carcinoma of Lung, its prognosis is evaluated on a case-by-case basis

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

  • Adenoid Cystic Carcinoma of Lung is normally observed in middle-aged and older adults; average age 55 years. It has a diagnostic peak in the age group of 40-60 years. Although, individuals of a wide age range may be affected
  • Both males and females are affected, though the condition is slightly more common in females than males (female-male ratio is 3:2)
  • ACC of Lung comprises less than 1% of all lung cancers (some studies show this value to be between 0.04-0.20%). It is a very rare form of cancer. But, there is no predilection for any particular racial or ethnic group

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

  • The risk factors for Adenoid Cystic Carcinoma of Lung are currently not well-established
  • Studies have not proven conclusively that smoking and excessive alcohol consumption are risk factors for ACC

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 Adenoid Cystic Carcinoma of Lung? (Etiology)

The cause of development of Adenoid Cystic Carcinoma of Lung is unknown. Some tumors have displayed a fused gene product of chromosome 6 and chromosome 9, called MYB-NFIB gene. This fused gene is caused by the translocation of chromosome 6 and 9.

  • 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
  • A poor diet and lack of physical activity may also contribute to the cause of cancer. Unhealthy food choices and avoiding physical activities can increase one’s likelihood of developing health risks, which could ultimately lead to cancerous tumor growth

What are the Signs and Symptoms of Adenoid Cystic Carcinoma of Lung?

Adenoid Cystic Carcinoma of Lung may present the following signs and symptoms:

  • ACC is a slow-growing and painless tumor with a potential to invade into the surrounding tissues. In many individuals, often no significant signs and symptoms are seen for many months and years
  • The tumor develops slowly and the growth rate varies from one individual to another. Often individuals have tumors growing for 5 years or more, after which they may present symptoms
  • An unpredictable growth pattern is recognized; the tumor grows slowly during the initial stages, but a sudden rapid growth may be visible after a certain time duration
  • The tumor infiltrates into the surrounding nerves and can cause pain, numbness, and tingling sensations
  • The adenoid cystic carcinoma can arise in the following lung parts:
    • Within the bronchial airways, in which case the tumor is known as Bronchial Adenoid Cystic Carcinoma
    • In the lung tissue or lung parenchyma, in which case the tumor is known as Pulmonary Adenoid Cystic Carcinoma
  • Usually a single mass is observed; a large mass may cause shortness of breath, blood in sputum, repeated coughing, and chest pain
  • Additional symptoms may include wheezing, hemoptysis (or blood in cough, which is commonly seen), weight loss, and pneumonia due to airways obstruction
  • Obstructive signs and symptoms are usually caused when the tumor is present in the bronchus. Tumors in the lungs tend to typically remain silent
  • Large tumors may cause a pressure effect by compressing adjoining structures and organs
  • Large tumors may ulcerate and bleed and become painful

How is Adenoid Cystic Carcinoma of Lung Diagnosed?

There are a variety of tests physicians may use to detect, locate, and diagnose Adenoid Cystic Carcinoma of Lung and to examine, if it has potentially spread to other regions. ACC of Lung is observed as a luminar mass in the bronchus, trachea, or main stem; or as a centrally located mass on a CT scan or chest radiograph.

A surgical procedure called a biopsy (usually performed by a radiologist or a cardiothoracic surgeon), is the only test a physician uses in order to make a definitive diagnosis of ACC of Lung. However, if a physician is unable to perform a lung biopsy due to the risk of damaging vital organs, additional tests will be recommended.

A diagnosis of Adenoid Cystic Carcinoma of Lung may involve the following:

  • Physical examination: During a physical exam, a physician will check the individual’s overall health status, listen to their breathing, and check for possible fluid buildup in the lungs (auscultation)
  • Chest X-ray: Two-dimensional pictures using tiny amounts of radiation are taken, in order to detect any tumors or other medical issues associated with the lungs, such as pneumonia. Tumors inside the lung, including Adenoid Cystic Carcinoma of Lung, which is usually on the periphery, can be detected using a chest X-ray; although sometimes, these tumors are too small to visualize
  • Computerized tomography (CT) scan: Also known as CAT scan, this radiological procedure creates detailed three-dimensional images of structures inside the body. CT scans are not a tool of preference to detect ACC of Lung; although, CT scans may be helpful in detecting recurrences, or if the cancer has metastasized to the surrounding lymph nodes of the lungs
  • Magnetic resonance imaging (MRI): 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 ACC of Lung is present
  • Arterial blood gases
  • Sputum cytology: Sputum cytology is test that involves the collection of mucus (sputum), coughed-up by a patient. After the mucus is collected, a pathologist examines in an anatomic pathology laboratory, if any cell abnormalities are present indicative of Pulmonary Adenoid Cystic Carcinoma
  • Pulmonary function tests can help determine the extent of lung damage and help the healthcare provider to assess the ability of lungs, to deliver oxygen to the body
  • Positron emission tomography (PET): A PET scan is a nuclear medicine imaging technique that uses three-dimensional images to show how tissue and organs are functioning. A small amount of radioactive material may be injected into a vein, inhaled or swallowed. A PET scan is also helpful in detecting recurrences, or if any metastasis (to the surrounding lymph nodes of the lungs) has occurred
  • Bone scan: A bone scan is a nuclear imaging test that involves injecting a radioactive tracer into an individual’s vein. Bone scans are primarily used to detect, if the cancerous cells in ACC of Lung, has metastasized to the bones and formed secondary tumors
  • Bone marrow biopsy: Bone marrow is a soft tissue found within bones. Occasionally, with ACC of Lung, a bone marrow biopsy is used to detect blood abnormalities, or if a physician thinks that metastasis to the bone marrow may have occurred

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 (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
  • 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:

  • 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: A differential diagnosis, to eliminate other tumor types is considered, before arriving at a conclusion.

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 Adenoid Cystic Carcinoma of Lung?

The complications of Adenoid Cystic Carcinoma of Lung may include the following:

  • Bleeding from the tumor can result in secondary infections of bacteria and fungus
  • Compression of the underlying nerve, which can affect nerve function
  • Obstruction of the airways, in case of a large-sized tumor
  • Large tumors may also compress the heart and impede its function
  • Dyspnea (shortness of breath): Individuals with Adenoid Cystic Carcinoma of the Lung may have an increased risk of exhibiting signs of dyspnea, if the cancerous tumor expands to block important large or small airways of the chest or lung
  • Hemoptysis (coughing-up blood): Individuals may cough-up blood, due to excessive amounts of blood in the airways
  • Pain: Advanced stages of Adenoid Cystic Carcinoma of the Lung that has metastasized to the pleural cavity (lining surrounding the lungs), invaded the chest wall, or other areas of the body, may cause excessive pain and agony
  • Pleural effusion (fluid in the chest): Excessive fluid accumulation, resulting from cancerous cells of ACC spreading inside the lungs, or outside of the lungs
  • In rare cases, partial collapse of the lung may occur
  • The tumor can metastasize to the nearby/local lymph nodes
  • In some occasions, tumor metastasis to distant sites including liver, lung, and bones, are observed. Metastasis often occurs due to a delay in diagnosis or due to a misdiagnosis
  • Recurrence of the tumor after a long period of time (years) on incomplete removal
  • 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 Adenoid Cystic Carcinoma of Lung Treated?

The treatment of Adenoid Cystic Carcinoma of Lung usually involves surgery, which is the first treatment option considered. This is followed by radiation therapy. In case of metastasis, chemotherapy may be employed by the healthcare provider.

  • In most cases, a wide surgical excision and removal of the entire tumor is the preferred treatment option. This is usually followed by radiation therapy. The surgical options may include:
    • Wedge resection: Wedge resection is a partial removal of the wedge-shape portion of the lung that contains cancerous cells (along with any surrounding healthy tissue)
    • Segmentectomy: Segmentectomy is also the partial removal of the cancerous lung and any surrounding healthy tissue
    • Lobectomy (pulmonary lobectomy): Lobectomy is the most common type of surgical procedure performed for Adenoid Cystic Carcinoma of Lung, to partially remove a portion of a lung
    • Sleeve lobectomy: Sleeve lobectomy is also a surgical procedure to partially remove a portion of the lung and a part of the airway (bronchus)
    • Pneumonectomy: It is the surgical removal of the entire lung
  • If the tumor has metastasized, then a combination of chemotherapy, radiation therapy, and invasive procedures may be used to treat the tumor
  • Post-operative care is important: A minimum activity level is ensured, until the surgical wound heals
  • Follow-up care with regular screening and check-ups are important and encouraged

Among individuals with KIT expression (mast cell growth factor receptor) in Adenoid Cystic Carcinoma of Lung, imatinib may be used as targeted therapy as it has demonstrated better survival among individuals with head and neck ACCs with KIT expression.

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 Adenoid Cystic Carcinoma of Lung be Prevented?

  • Currently, there are no known methods to prevent Pulmonary Adenoid Cystic Carcinoma occurrence
  • 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 Adenoid Cystic Carcinoma of Lung? (Outcomes/Resolutions)

  • The prognosis of Adenoid Cystic Carcinoma of Lung is generally unpredictable and can only be assessed on a case-by-case basis. In some individuals, the life expectancy is long, even after metastatic stage (advanced disease)
  • Studies show that some have lived for 30-40 years after diagnosis. However, in some, because of a rapid growth, the life expectancy may be substantially decreased to a few years. The tumors can recur years after surgery/radiation
  • Also, despite a slow-growing growth pattern, the National Cancer Institute (USA) considers adenoid cystic carcinoma as a high-grade malignancy. Hence close follow-up for a long duration (sometimes, even for several decades) is necessary
  • The prognosis of Adenoid Cystic Carcinoma of Lung/Bronchus 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 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
    • 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 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: 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
  • Adenocystic carcinoma recurs multiple times in the pleural cavity, chest wall, and mediastinum or lung tissue, before metastasis. Metastasis to regional lymph node is observed in 20% of the cases, and metastasis to other organs, seen in 40% of the cases
  • Overall, Adenoid Cystic Carcinoma of Lung has a poor prognosis and a prolonged disease course. Positive tumor margin and a solid tumor growth pattern are associated with poor prognosis
  • 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 Adenoid Cystic Carcinoma of Lung:

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Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Dec. 31, 2013
Last updated: March 30, 2018