Some clinical entities are not entirely known, and there are many less-frequent variants. When that happens, it is sometimes useful to include the least common variants in a new category, and that is what happens with large cell carcinomas. They are also known as large cell undifferentiated carcinomas, a category of non-small cell lung carcinoma that includes different lung cancer variants that do not enter any other type.
In this article, we’re briefly going through large cell carcinoma, its causes, diagnosis, and prognosis.
What Is Large-Cell Carcinoma Of The Lungs?
In simple words, large cell carcinoma is a category that includes any malignant neoplasm of the lung that is not small cell carcinoma, squamous carcinoma, or adenocarcinoma. This is a very heterogeneous group of cancer, and it is used as a diagnosis of exclusion in the group of non-small cell carcinomas.
Large undifferentiated carcinomas sometimes display similar features to those found in adenocarcinoma or squamous cell carcinoma. Some of them may even have secretory granules and undifferentiated features.
Less than 10% of lung cancer will be large cell undifferentiated carcinoma. The number of cases is dropping lately because new technologies and histologic findings have revealed the true nature of the tumors, detecting more cases of squamous cell carcinoma and glandular carcinoma that were formerly included in this cancer group.
What Causes Large-Cell Carcinoma Of The Lungs?
Large cell carcinoma comprises a very heterogeneous group of lung cancer, and none of them has been widely studied. However, most risk factors and causes of lung cancer also apply to this subtype.
A history of smoking is a common finding in these patients, especially in older adults. In most cases, patients have a duration of the smoking habit of 30 or 40 years before large cell carcinoma shows up. The median age of diagnosis of this type of cancer is 60 years old, and other causes include exposition to radon and passive smoking.
Warning Signs and Early symptoms
The presenting signs and symptoms of large cell carcinoma are similar to the rest of lung cancers. Some of them are associated with a primary lesion in the lungs. Others are related to spreading inside of the thorax or distant metastasis.
The most common symptoms include cough, chest pain, and hemoptysis (coughing up blood). We can also find changes in the tone of voice, such as hoarseness or a raspy voice. In the case of metastasis, we will also have symptoms such as bone pain and various symptoms associated with the central nervous system depending on the site of the spread.
These patients typically display constitutional symptoms as well. They are unspecific but relate to the severity of the disease. The most common include weight loss, weakness, and loss of the patient’s appetite. In some cases, we can also have fever as a symptom, but it is quite rare.
Large cell carcinoma is a very complex entity, and most cases only give out alarming signs when the disease is very advanced. Thus, it is imperative to evaluate patients as soon as possible if they have a chronic coughing history, even if they are not coughing up blood. If they are older than 40 years and have a positive history of smoking, they should be promptly evaluated to rule out lung cancer.
Persistent pneumonia that does not respond to different antibiotics is also an alarming sign that something is going on. Another sign found in the physical exam is tenderness in the ribs when there is an invasion of the pleura and involvement of the chest wall.
Diagnosis and Prognosis
In the diagnosis of large cell carcinoma of the lungs, the first step is considering the patient’s signs and symptoms. It is usually a senior with a chronic cough that has recently started to cough up blood. Chest pain is sometimes present and could be located in any part of the chest.
The first exam to diagnose the disease is a chest radiograph, which shows a large mass in the lungs. This mass can be located in any part of the lung, but it usually occurs peripherally, not in the center of the lung. Other exams can be performed to examine the extent of the mass and define its borders. CT-scans are particularly useful for that.
But diagnosing the type of lung cancer requires performing a histologic evaluation of the lesion after a lung cancer biopsy. It is a diagnosis of exclusion, which means that more common types of lung cancer are ruled out, and if the tumor does not follow the pattern of any of them, the diagnosis of large-cell lung cancer is then considered. That is why it is also known as large cell undifferentiated lung cancer. Since they are relatively more difficult to diagnose, these tumors are usually very large compared to other types. They are attached to the pleura and may start invading other organs in the chest.
The histologic findings often reveal areas of hemorrhage and necrosis of the tissue. They have a solid growth pattern, and their cells have a polygonal or cuboidal form, with large or medium size.
After diagnosing this type of cancer, we can also break it down into different morphologic variants according to what we see in the biopsy:
- Basaloid carcinoma
- Large cell neuroendocrine carcinoma
- Combined large cell neuroendocrine carcinoma
- Large cell carcinoma with rhabdoid features
- Clear cell carcinoma
- Giant cell carcinoma
- Lymphoepithelioma-like carcinoma
There are very few studies of each one of the types above. Thus, the prognosis is sometimes uncertain. It is important to remember that each case should be evaluated individually. Your prognosis will be different depending on your age, the comorbidities, the size and extent of cancer, and the variant. Talk to your doctor about it if you want a personalized answer that applies only to you.
References:
Gollard, R., Jhatakia, S., Elliott, M., & Kosty, M. (2010). Large cell/neuroendocrine carcinoma. Lung Cancer, 69(1), 13-18.
Cersosimo, R. J. (2002). Lung cancer: a review. American journal of health-system pharmacy, 59(7), 611-642.
