What happens when the hilum of the lung is abnormal? (2023)

The hilum of the lung is the wedge-shaped area in the central portion of each lung, located at theMedial (median) aspect of each lung. The hilar region is where thebronchi, arteries, veins, and nerves enter and leave the lungs.

This area can be difficult to see on a chest X-ray, and additional tests such as a CT scan (sometimes, but not always, requires contrast dye) are needed to determine if there is a problem.

Hilar enlargement can occur due to tumors (such as lung cancer), pulmonary hypertension, or enlarged hilar lymph nodes due to conditions such as infections (especially tuberculosis and fungal infections), cancer (local or metastatic), sarcoidosis, and more.

An Overview of Pulmonary Hypertension

What happens when the hilum of the lung is abnormal? (1)

Hilum Anatomy

Both the right and left lungs have a hilum that is located approximately in the middle of the lungs and slightly to the rear (closer to the vertebrae than to the front of the thorax). Each lung can be visualized with a vertex (the top), a base (the bottom), a root, and a hilum.

(Video) The Pulmonary Hila

The main bronchi, pulmonary arteries, pulmonary veins, and nerves are the structures that enter and leave the lungs in this region.lymph nodes, called hilar lymph nodes, are also present in this region. Both hilum are similar in size, with the left hilum generally lying slightly higher on the thorax than the right hilum.

Tests to evaluate the hilum

Abnormalities in the hilum are usually seen on imaging studies, but additional tests and procedures are often needed to determine if and where a problem exists.


On chest radiography, the hilar region reveals a shadow consisting of a combination of lymph nodes, pulmonary arteries, and pulmonary veins.

Due to the overlap of these structures, it can sometimes be difficult to detect enlargement of these lymph nodes or the presence of a mass in this region. this is one of the reasons whyChest X-rays May Miss Lung Cancer.

Chest CT (with or without contrast) can lead to better visualization of these structures. TOpositron emission tomography (PET)it is sometimes very helpful if a tumor is suspected.

radiology report

When a radiologist views the hilum, they will report whether there is symmetry between the right and left hilum, as well as the following:

  • Mould: A branched (blood vessel) appearance is normal.
  • radiopacity: The hilum is usually denser centrally, appearing darker at the periphery on a chest x-ray or CT scan.
  • size provided: Most (approximately two-thirds) of the vascular density should be in the lower part of the hilum.
  • absolute size: Any enlargement of the hilum will be noticeable, but most of the time there needs to be a significant degree of enlargement to be seen.

Depending on the specific study, the radiologist may note hilar enlargement and whether there is a hilar mass or hilar lymphadenopathy (enlarged hilar lymph nodes).

(Video) the dense hilum sign


In addition to imaging tests, abnormalities in the hilar region can be identified with tests such asbronchoscopy, a test in which a tube is inserted through the mouth into the main airways (bronchi).

Ultrasound done through an ultrasound probe inserted during a bronchoscopy (aendobronchial ultrasound) can sometimes take samples of abnormal tissue near the main airways.

a test calledmediastinoscopia(a surgical procedure in which a surgeon can explore the area between the lungs, including the hilar lymph nodes) may be needed to better visualize the region or to obtain a biopsy sample, although PET has replaced the need for this procedure in several cases.

Hilar enlargement/hilar masses

The hilar region of the lung may be affected by tumors (including primary tumors and metastatic tumors), enlargement of the hilar lymph nodes, or abnormalities of the pulmonary arteries or veins.


Enlargement of the hilum can be seen when imaging studies are done to evaluate symptoms such as a persistent cough, coughing up blood, shortness of breath, or recurrent respiratory infections, or it can be found accidentally on a test such as a CT scan. Both masses and enlarged lymph nodes can be caused by cancer or by benign causes.

Causes of enlarged lymph nodes

Location of masses or lymphadenopathy

Some apparent hilum abnormalities may simply be due to position, and other views may rule out problems. If a mass or enlargement is noted, the possible causes may vary based on appearance:

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  • Symmetrical enlargement (bilateral): Enlargement of both hilar regions may suggest conditions such as sarcoidosis or pulmonary hypertension.
  • Asymmetric (unilateral) enlargement: When only one hilar region is enlarged, causes such as tumors are more likely.
  • Displacement: The hilar region may be displaced (be in a different position than usual) in conditions such as pneumothorax.


There are four main reasons why the hilum of one or both lungs may look enlarged on an x-ray. These include:

  • Tumors and lymphadenopathy: Cancers such as lung cancer and lymphomas, as well as cancer that has spread to this region from other parts of the body (metastatic cancer) can cause masses in this region. Possible causes of enlarged hilar lymph nodes (lymphadenopathy) are discussed below.
  • Pulmonary venous hypertension(elevated pressure in the pulmonary veins): Pulmonary venous hypertension can occur due to medical conditions such as heart failure and heart valve problems such as mitral stenosis and mitral regurgitation.
  • Pulmonary arterial hypertension(PAH): This is high pressure in the pulmonary arteries. PAH can occur as a primary disease (not secondary to another problem) or as a secondary problem that, in turn, is most often caused bychronic obstructive pulmonary disease(COPD).
  • Increased pulmonary blood flow: Conditions such as cyanotic congenital heart disease (heart defects present at birth that cause a bluish tinge to the skin due to reduced oxygen content) can cause increased pulmonary blood flow.

hilar lymphadenopathy

Enlarged lymph nodes in the hilum can occur in both the right and left hilum (bilateral lymphadenopathy) or only on one side (asymmetric lymphadenopathy). Causes may include:

  • lung cancer:lung cancerit is the most common cause of ragged hilar regions in adults, both from the presence of a tumor and from the presence of involved lymph nodes.
  • other types of cancer: Metastatic breast cancer can cause hilar adenopathies both due to the spread of the cancer to this region and to the affected lymph nodes. Lymphoma and other mediastinal tumors can also cause enlarged hilar lymph nodes.
  • Tuberculosis: World,tuberculosisIt is one of the most common causes of hilar adenopathy in children.
  • Inflammation: Conditions such as sarcoidosis,amilosis, and silicosis can cause hilar lymphadenopathy.sarcoidosisIt is the most common cause of bilateral hilar lymph node enlargement, especially in young adults. Hilar lymph node enlargement with sarcoidosis is often symmetrical in contrast to other common causes. Drug reactions are also a relatively common cause of hilar adenopathy.
  • Other infections: Infections such as mycobacteria, viral infections such as infectious mononucleosis, berylliosis, tularemia, histoplasmosis, andcoccidioidomicosait can lead to enlarged lymph nodes in this region. In the United States, histoplasmosis is common in the Ohio and Mississippi river valleys, with coccidioidomycosis being most common in the southwestern states.
  • other causes:Castleman's diseaseIt is a condition characterized by abnormal lymphatic tissue. Heart failure can also lead to hilar adenopathy.

A word from Verywell

There are several conditions that can cause the hilum to appear abnormal on imaging studies, many of which are serious.

However, the first step is to ensure that any findings are not simply due to poor body position during the making of these films. With the number of structures that pass through this area, even a slight rotation can give the appearance of an abnormality when there is none.

Tumors, both primary and metastatic, are a very common cause of hilar masses and lymphadenopathy. Common causes generally include tuberculosis worldwide and conditions such as histoplasmosis, coccidioidomycosis, and sarcoidosis in the United States.

If your doctor notices an abnormality on your exam, additional tests will be ordered. They will also request a detailed history to look for any other symptoms that suggest a tumor, infection, or inflammatory process. Most of the time, a biopsy will be needed to get a definitive diagnosis.

frequent questions

  • Where is the hilum of the lung?

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    The hilum is located at the back of each lung, between the fifth and seventh thoracic vertebra. It is where the bronchi, veins, arteries and nerves enter and leave the lung.

  • Where are the hilar lymph nodes located?

    Hilar lymph nodes are located in the area where the bronchus enters the lung.

  • What is hilar adenopathy?

    (Video) Causes of Interstitial Shadow on Chest X-ray | Differential Diagnosis & Mnemonic to Remember Causes

    Hilar adenopathy is enlargement of the lymph nodes in the hilum. It can be caused by conditions such as tuberculosis, sarcoidosis, drug reactions, infections, or cancer.


What is hilar abnormality? ›

The hila consist of vessels, bronchi and lymph nodes. On a chest X-ray, abnormalities of these structures are represented by a change in position, size and/or density.

Is a hilar mass always cancer? ›

Hilar adenopathy is the enlargement of lymph nodes in the hilum. It can be caused by conditions such as tuberculosis, sarcoidosis, drug reactions, infections, or cancer.

What is the most common cause of hilar enlargement? ›

Inflammatory Disease

Primary tuberculosis usually causes unilateral hilar adenopathy. Fungal infections, most notably histoplasmosis and coccidioidomycosis, cause unilateral or bilateral adenopathy. Sarcoidosis causes bilateral and symmetrical adenopathy in most patients (see Fig.

Can a hilar mass be cured? ›

Based on the results of early hilar lung carcinoma, we concluded that these lesions are curable if they are properly diagnosed and treated.

What does hilum of lung mean in medical terms? ›

What is the hilum? The hilum is what connects your lungs to their supporting structures and where pulmonary vessels enter and exit your lungs. The hilum — or root — functions much like a plant root, securing each lung in place and providing a channel for energy to pass through.

What does the hilum of the lung do? ›

The hilum (root) is a depressed surface at the center of the medial surface of the lung and lies anteriorly to fifth through seventh thoracic vertebrae. It is the point at which various structures enter and exit the lung. The hilum is surrounded by pleura, which extends inferiorly and forms a pulmonary ligament.

How can you rule out lung cancer? ›

The only recommended screening test for lung cancer is low-dose computed tomography (also called a low-dose CT scan, or LDCT). During an LDCT scan, you lie on a table and an X-ray machine uses a low dose (amount) of radiation to make detailed images of your lungs. The scan only takes a few minutes and is not painful.

What can be mistaken for lung cancer? ›

12 Diseases That Lung Cancer Is Commonly Misdiagnosed As
  • Pneumonia.
  • Asthma.
  • Chronic obstructive pulmonary disease (COPD)
  • Acid reflux.
  • Gastroesophageal reflux disease (GERD)
  • Encysted lung effusion.
  • Lung abscesses.
  • Lung nodules.

What can a lung mass be if not cancer? ›

Types of benign lung tumors include hamartomas, adenomas and papillomas. In almost all cases, benign lung tumors require no treatment, but your doctor will probably monitor your tumor for changes.

What does the medical term hilar mean? ›

Listen to pronunciation. (HY-ler) Refers to the area where nerves and blood vessels attach to an organ.

What is hilar infection? ›

Hilar lymphadenopathy is a common radiological finding associated with fungal infections, mycobacterial infections, and sarcoidosis.

What does increased hilar markings mean? ›

Hilar enlargement reflects one of 4 types of processes: Lymphadenopathy and tumors. Pulmonary venous hypertension. Pulmonary arterial hypertension. Increased pulmonary blood flow.

What is the treatment for hilar mass? ›

Hilar lung tumor patients may be treated with frameless stereotactic radiosurgery, resulting in encouraging early clinical responses, acceptable acute toxicity and reliable palliation.

What percentage of lung masses are cancerous? ›

Most lung nodules are benign, or non-cancerous. In fact, only 3 or 4 out of 100 lung nodules end up being cancerous, or less than five percent.

How do you get rid of hilar lymph nodes? ›

The excision of the hilar lymph nodes is carried out during the bronco-vascular dissection. The mediastinal lymph nodes dissection can be performed before the lobectomy in order to simplify the isolation of the bronco-vascular structures. The lymph nodes removed should be separately labeled and examined histologically.

What is the hilum on chest xray? ›

The lung roots, or hila (singular – hilum), are complicated anatomical structures containing the pulmonary vessels and the major bronchi, arranged asymmetrically. Although the hilar lymph nodes are not visible on a normal chest X-ray, they are of particular importance clinically.

What does it mean if hilum is dense? ›

The dense hilum sign suggests a pathological process at the hilum or in the lung anterior or posterior to the hilum. Malignancy, especially lung cancer, should be suspected.

What is hilar malignancy? ›

Hilar cholangiocarcinoma is a type of bile duct cancer that occurs in the bile ducts that lead out of the liver (hepatic ducts) and join with the gallbladder. Hilar cholangiocarcinomas are also known as Klatskin tumors.

What does hilar lymph nodes mean in medical terms? ›

noun, plural: hilar lymph nodes. Any of the lymph nodes in the hilum or the triangular depression or indented region at the junction of each lung and its bronchi. Supplement. Hilar lymph nodes collect lymph from the pulmonary nodes, and drain to the tracheobronchial nodes.

What lobe is the hilum in? ›

In the right hilum the bronchus of the upper lobe and the branch of the right pulmonary artery to the upper lobe originate prior to entering the hilum. Thus, the upper lobe bronchus and artery are found above the level of the right main bronchus and right pulmonary artery.

What are the symptoms of Stage 1 lung cancer? ›

Stage 1 lung cancer symptoms
  • New cough that persists.
  • Chronic cough that gets worse.
  • Coughing up bloody mucus.
  • Shortness of breath.
  • Ongoing chest pain.
  • Frequent lung infections.

What is the first stage of diagnosing lung cancer? ›

A chest X-ray is usually the 1st test used to diagnose lung cancer. Most lung tumours appear on X-rays as a white-grey mass.

Where does lung cancer usually start in the lungs? ›

Lung cancers typically start in the cells lining the bronchi and parts of the lung such as the bronchioles or alveoli. A thin lining layer called the pleura surrounds the lungs. The pleura protects your lungs and helps them slide back and forth against the chest wall as they expand and contract during breathing.

What are the sneaky signs of lung cancer? ›

The most common symptoms of lung cancer are:
  • A cough that does not go away or gets worse.
  • Coughing up blood or rust-colored sputum (spit or phlegm)
  • Chest pain that is often worse with deep breathing, coughing, or laughing.
  • Hoarseness.
  • Loss of appetite.
  • Unexplained weight loss.
  • Shortness of breath.
  • Feeling tired or weak.
Oct 1, 2019

How does lung cancer usually start? ›

Cigarette smoking is the number one cause of lung cancer. Lung cancer also can be caused by using other types of tobacco (such as pipes or cigars), breathing secondhand smoke, being exposed to substances such as asbestos or radon at home or work, and having a family history of lung cancer.

Where do you feel lung cancer pain? ›

In its early stages, lung cancer doesn't typically have symptoms you can see or feel. Later, it often causes coughing, wheezing, and chest pain.

What size of lung nodule is worrisome? ›

Nodules between 6 mm and 10 mm need to be carefully assessed. Nodules greater than 10 mm in diameter should be biopsied or removed due to the 80 percent probability that they are malignant. Nodules greater than 3 cm are referred to as lung masses.

How do you know if a lung mass is cancerous? ›

A CT scan usually isn't enough to tell whether a lung nodule is a benign tumor or a cancerous lump. A biopsy is the only way to confirm a lung cancer diagnosis.

How fast do lung nodules grow if cancerous? ›

Cancerous pulmonary nodules, however, are known to grow relatively quickly—usually doubling in size every four months but sometimes as fast as every 25 days. A cancerous nodule is a lesion or “sore” that steadily engulfs more and more of the structures of the lung.

What is enlarged mediastinal and hilar lymph nodes? ›

Hilar and mediastinal node enlargement may be a manifestation of the spread of renal tumours. However, the author believes the spread to these nodes may occur either via the upper para-aortic nodes or directly by way of lymphatic vessels from the kidneys by-passing the upper abdominal nodes.

What is enlarged mediastinal and bilateral hilar lymph nodes? ›

Bilateral hilar lymphadenopathy is a bilateral enlargement of the lymph nodes of pulmonary hila. It is a radiographic term for the enlargement of mediastinal lymph nodes and is most commonly identified by a chest x-ray.

How do you know if a lung infection is serious? ›

See your doctor if you have difficulty breathing, chest pain, persistent fever of 102 F (39 C) or higher, or persistent cough, especially if you're coughing up pus. It's especially important that people in these high-risk groups see a doctor: Adults older than age 65.

Can you biopsy hilar lymph node? ›

Abstract. Background: Because of their proximity to the pulmonary artery or vein, hilar lymph nodes are routinely biopsied with endobronchial or endoscopic ultrasonography (EUS)-guided fine-needle aspiration biopsy (FNAB).

What are the causes of increased lung markings? ›

  • Neoplastic infiltration (lymphangitic carcinomatosis, lymphoma)
  • Sarcoidosis.
  • Collagen-vascular diseasesInterstitial pneumonitis.
  • Idiopathic pulmonary fibrosis.
  • Pneumoconiosis (silicosis, asbestosis)
Feb 22, 2023

What does hilar mean in medical terms? ›

Listen to pronunciation. (HY-ler) Refers to the area where nerves and blood vessels attach to an organ.

How do you treat hilar lymph nodes? ›

In patients with acceptable operative risk, surgical resection with adjuvant chemotherapy forms the cornerstone of treatment for hilar node-positive (N1) disease.

What is the meaning of hilar lymph nodes? ›

noun, plural: hilar lymph nodes. Any of the lymph nodes in the hilum or the triangular depression or indented region at the junction of each lung and its bronchi. Supplement. Hilar lymph nodes collect lymph from the pulmonary nodes, and drain to the tracheobronchial nodes.

What are the signs that you have a cancerous lymph node? ›

  • Painless swelling of lymph nodes in your neck, armpits or groin.
  • Persistent fatigue.
  • Fever.
  • Night sweats.
  • Shortness of breath.
  • Unexplained weight loss.
  • Itchy skin.
Dec 14, 2022

Can hilar lymph nodes cause pain? ›

People with swollen lymph nodes in the chest might not notice any symptoms. However, the swollen lymph nodes sometimes push on organs or other structures, which may cause pain.

How is a hilar lymph node biopsy done? ›

A small surgical cut is made just above the breastbone. A device called a mediastinoscope is inserted through this cut and gently passed into the mid-part of the chest. Tissue samples are taken of the lymph nodes around the airways. The scope is then removed and the surgical cut is closed with stitches.

What causes enlarged mediastinal and hilar lymph nodes? ›

The initial clue to the presence of enlarged mediastinal lymph nodes is through thoracic imaging modalities. Malignancy (Lung cancer, lymphoma, and extrathoracic cancer) and granulomatous conditions (sarcoidosis and tuberculosis) are the most common causes.

What does enlarged mediastinal and hilar lymph nodes mean? ›

Hilar and mediastinal node enlargement may be a manifestation of the spread of renal tumours. However, the author believes the spread to these nodes may occur either via the upper para-aortic nodes or directly by way of lymphatic vessels from the kidneys by-passing the upper abdominal nodes.

Where do hilar lymph nodes drain into? ›

These usually drain directly into the junction of the internal jugular and subclavian veins on each side, but may drain, on the right, into the right lymph trunk and, on the left, into the thoracic duct.

What drains into hilar lymph nodes? ›

The most superficial layer, which is the parietal pleura, drains its lymphatic content ventrally to the parasternal nodes and dorsally to the intercostal nodes. The visceral pleural, on the other hand, drain via the deep pulmonary plexus to the hilar nodes.


1. Do you know the hilum overlay sign on chest x-rays?
(Radiology Masters)
2. Restrictive lung disease - causes, symptoms, diagnosis, treatment, pathology
(Osmosis from Elsevier)
3. The Respiratory System - Anatomy of the Lungs. Anatomy made Fun, Exams made Easy.
4. What is Hilum? | How to view Hilar System in Xray? | Chest X ray
(Physio Talk)
5. Significance of solitary lung calcification in X ray and its prognosis - Dr. Sanjay Gupta
(Doctors' Circle World's Largest Health Platform)
6. CXRs, Hilar Lymphadenopathy and High Yield Associations for the USMLE
(Blueprint Med School)


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