Introduction

Follicular lymphoma (FL) is a form of non-Hodgkin lymphoma, a type of cancer that occurs in the lymphatic system. It is a slow-progressing lymphoma (indolent lymphoma) that affects B lymphocytes, which are a type of white blood cells that produce antibodies during the body’s immune response to foreign organisms.It is named follicular due to the fact that the cells form bundles known as follicles. Since it is an indolent lymphoma, its symptoms progress very slowly and may not appear until later in age, usually around 55 to 60 years old.^1,2

In follicular lymphoma, B cells become malignant, evade programmed cell death (apoptosis) and are able to survive despite being defective both in shape and function. They also lose their ability to produce antibodies and adequately fight infections.  These B cells will then start to multiply and accumulate inside lymph nodes, areas in the lymphatic system responsible for filtering lymph. They may also develop in other areas of the body such as the abdomen, spleen and bone marrow. Approximately 50% of all follicular lymphomas will eventually reach the bone marrow.²

It is important to recognise symptoms early on and receive proper assessment from a medical professional. The person will undergo some tests and imaging with CT or PET scans, and a diagnosis is only confirmed after a biopsy sample of lymph nodes is observed and the presence of follicles is detected. Treatment strategies span from observing symptoms and their evolvement to using radiotherapy or immunochemotherapy with agents like rituximab, which has proven quite efficient in improving survival rates.^1,2

Common symptoms of Follicular lymphoma

Lymphadenopathy (swollen lymph nodes)

Lymphadenopathy is the most common symptom of lymphoma. Lymph nodes act by filtering the contents of the lymph and are found throughout the body. These nodes may become enlarged in the course of an infection, but the swelling will disappear once the infection is cleared.

In follicular lymphoma, malignant B cells multiply and accumulate in the form of clusters in the lymph nodes, resulting in masses that can be noticed when touching the neck, armpits or groins. These swellings are usually not accompanied by any pain or discomfort but might appear in more than one area and will be present for many weeks. Sometimes, the lymph nodes affected are not under the skin directly and the masses are not palpable. In this case, the person may experience other symptoms arising from the masses pressing on the adjacent organs.³

B symptoms

Follicular lymphoma carries the risk of evolving into a more dangerous and aggressive lymphoma known as diffuse large B-cell lymphoma (DLBCL). When this happens, the person may experience new symptoms called B symptoms. Around 20% of people with follicular lymphoma may develop these symptoms which are used to determine the stage of the disease. B symptoms include 

• Having a persistent fever of 38°C or higher that might come and go without an infection or an explicable reason
• Sweating profusely at night, wetting their clothes and drenching their bed sheets 
• Losing more than 10% of the body weight over a period of 6 months unintentionally without any diet or weight loss measures 

Less common symptoms

Fatigue

A person with follicular lymphoma may feel tired most of the time despite not overexerting themselves. They may find it hard to accomplish tasks and activities they usually carry out easily. Their thinking process and mood are affected as well. This fatigue will remain despite getting a good night’s sleep or resting for a considerable amount of time. 

Fatigue can be caused as a result of the body’s response in trying to fight the cancer and its progression. It can also be a symptom of anaemia that can result from lymphoma developing in the bone marrow, where oxygen-carrying red blood cells are made.⁴

Abdominal symptoms

When follicular lymphoma affects lymph nodes in the abdomen, the swellings may press on adjacent tissues or organs. Examples of this include experiencing abdominal pain and feeling of discomfort. One might also feel full and satiated despite not eating much, as the mass will occupy a space near the stomach and reduce its filling capacity. 

• If the lymphoma takes place in the spleen, the size of this organ might increase and press on surrounding body parts possibly causing pain 
• The liver might also become involved, leading to symptoms of jaundice like the skin and the whites of the eyes becoming yellowish. It might also trigger the buildup of fluid in the abdomen, known as ascites
• The lining of the stomach and the bowels might also become swollen causing more pain, vomiting and a change in bowel habits between constipation and diarrhoea⁵

Skin rash or itching

Rashes and itching might also arise in different parts of the skin as a symptom of follicular lymphoma. The probable cause of this might be some of the byproducts released by the malignant cells. It can also be the result of some substances that the immune system releases when dealing with this condition. It should be noted that the itching is not always accompanied by a rash, and in some cases, it might be caused by other skin conditions, like dry skin and dermatitis, that are unrelated to the lymphoma.⁶

Bleeding and bruising

In rare cases, the person might notice that they start to bruise more easily than they usually do and their gums and nose might bleed often too. This could be linked to a decrease in platelet production when the lymphoma occurs in the bone marrow. Any signs of unexplained bruising or bleeding should always be reported to a healthcare provider to allow them to investigate the cause behind it.⁷

Advanced symptoms (in later stages)

Bone pain

Although very rare, follicular lymphoma can affect bone tissues in advanced stages. This will manifest as bone pain where the cancer has metastasised such as in the hips, knees, back or shoulder.⁸

Anaemia

As mentioned previously, the bone marrow may become affected in almost half of those having follicular lymphoma. The bone marrow is responsible for the production of red blood cells. These cells carry oxygen throughout the body to allow different parts to function properly. If their levels are low, not enough oxygen is distributed and the person might become easily tired and breathless. If anaemia is suspected, medical help should be sought from a healthcare provider to investigate the cause behind these symptoms.

Increased risk of infections

Having follicular lymphoma might increase susceptibility to different infections. If the bone marrow is affected, its production of white cells might be influenced and the level of these cells that fight infections diminished. This coupled with the abnormal multiplication of malignant B lymphocytes that may not release any or sufficient antibodies, will also compromise the immune system.

As a result, the body will not be able to fight off simple infections efficiently, and recovery from these infections will take longer than it usually does.⁹

Summary

Follicular lymphoma is the second most common non-Hodgkin lymphoma with a slow progression course and symptoms that may go undetected for quite some time. It manifests mainly through the appearance of lumps in the lymph nodes throughout the body. These swellings can be felt if they form under the skin in areas like the neck, armpits or groins. They may also occur in parts where they cannot be detected by palpation, for example in the abdomen, spleen or bone marrow.

Other symptoms that a person can experience as a result of follicular lymphoma are fatigue and abdominal pain. The latter can be a result of lymphadenopathy occurring in the abdominal cavity organs, like the spleen, liver, stomach and bowels. In this case, the pain may also be accompanied by other symptoms like jaundice, nausea and diarrhoea. If the lymphoma progresses, the person might have B symptoms, which involve night sweats, losing weight unintentionally and having fevers without any specific cause for them.

If the lymphoma reaches the bone marrow, the centre of blood cell production, the person might develop anaemia, bleeding and bruising and an increased susceptibility to infections caused by a decrease in red blood cells, platelets and white blood cells, respectively.

If a person suspects that they might be having symptoms suggestive of follicular lymphoma, they should seek medical opinion immediately. They will have to undergo a series of tests and scans to determine whether their symptoms are related to the condition. A diagnosis is only made after observing a biopsy sample from the lymph nodes which confirms the presence of malignant cells in follicles.