Non-Hodgkin lymphoma overview

# Overview
Non-Hodgkin lymphomas (NHLs), are diverse group of blood cancers that include any kind of lymphoma except Hodgkin's lymphomas. Lymphomas are types of cancer derived from lymphocytes, a type of white blood cell. Non-Hodgkin lymphoma may be classified into subtypes according to updated WHO classification and rate of growth. There are no established causes for non-Hodgkin lymphoma. Non-Hodgkin lymphoma must be differentiated from Hodgkin's disease, viral infections, metastatic carcinoma, and autoimmune diseases. In 2015, the incidence of non-Hodgkin lymphoma was estimated to be 24 cases per 100,000 individuals in the United States. In the United States, the age-adjusted prevalence of non-Hodgkin lymphoma is 131.1 per 100,000 individuals in 2011. The known risk factors in the development of non-Hodgkin lymphoma are weakened immune system, autoimmune disorders, certain infections and previous cancer treatment. Other possible risk factors include positive family history of non-Hodgkin lymphoma, exposure to pesticides, exposure to trichloroethylene, diet, obesity, hair dyes, and occupational exposures. Common complications of non-Hodgkin lymphoma include autoimmune hemolytic anemia and infection. The indolent non-Hodgkin lymphoma types are associated with a relatively good prognosis. According to the Ann Arbor staging system, there are four stages of non-Hodgkin lymphoma based on the number of nodes and extra nodal involvement. The most common symptom of non-Hodgkin lymphoma is painless swelling of the lymph nodes in the neck, underarm (axilla), or groin. Other symptoms of non-Hodgkin lymphoma may include fever, weight loss, poor appetite, night sweats, constant fatigue, itchy skin, reddened patches on the skin, cough, shortness of breath, abdominal pain or swelling, constipation, nausea, vomiting, headache, concentration problems, personality changes, and seizures. Common physical examination findings of non-Hodgkin lymphoma include fever, pruritus, petechiae, chest tenderness, abdominal tenderness, hepatomegaly, splenomegaly, peripheral lymphadenopathy, seizures, and central lymphadenopathy. Laboratory tests for non-Hodgkin lymphoma include complete blood count (CBC), blood chemistry studies, HIV blood test, and hepatitis B blood test. On chest x ray, non-Hodgkin lymphoma is characterized by nodules and pleural effusion. CT and MRI scan may be helpful in the diagnosis of non-Hodgkin lymphoma. On ultrasound, non-Hodgkin lymphoma is characterized by hepatomegaly and  splenomegaly. Lymph node or extra nodal tissue biopsy is diagnostic of non-Hodgkin lymphoma. PET and bone scan may be helpful in the diagnosis of non-Hodgkin lymphoma. Other diagnostic studies for the diagnosis of non-Hodgkin lymphoma include bone marrow aspiration, bone marrow biopsy, and lumbar puncture. The predominant therapy for non-Hodgkin lymphoma is chemotherapy. Adjunctive radiation, immunotherapy, and stem cell transplantation may be required. Surgical intervention is not recommended for the management of non-Hodgkin lymphoma.

# Classification
Non-Hodgkin lymphoma may be classified into subtypes according to updated WHO classification and rate of growth.

# Causes
There are no established causes for non-Hodgkin lymphoma.

# Differential Diagnosis
Non-Hodgkin lymphoma must be differentiated from Hodgkin's disease, viral infections, metastatic carcinoma, and autoimmune diseases.

# Epidemiology and Demographics
In 2015, the incidence of non-Hodgkin lymphoma was estimated to be 24 cases per 100,000 individuals in the United States. In the United States, the age-adjusted prevalence of non-Hodgkin lymphoma is 131.1 per 100,000 individuals in 2011.

# Risk Factors
The known risk factors in the development of non-Hodgkin lymphoma are weakened immune system, autoimmune disorders, certain infections and previous cancer treatment. Other possible risk factors include positive family history of non-Hodgkin lymphoma, exposure to pesticides, exposure to trichloroethylene, diet, obesity, hair dyes, and occupational exposures.

# Complications and Prognosis
Common complications of non-Hodgkin lymphoma include autoimmune hemolytic anemia and infection. The indolent non-Hodgkin lymphoma types are associated with a relatively good prognosis.

# Diagnosis

## Staging
According to the Ann Arbor staging system, there are four stages of non-Hodgkin lymphoma based on the number of nodes and extra nodal involvement.

## Symptoms
The most common symptom of non-Hodgkin lymphoma is painless swelling of the lymph nodes in the neck, underarm (axilla), or groin. Other symptoms of non-Hodgkin lymphoma may include fever, weight loss, poor appetite, night sweats, constant fatigue, itchy skin, reddened patches on the skin, cough, shortness of breath, abdominal pain or swelling, constipation, nausea, vomiting, headache, concentration problems, personality changes, and seizures.

## Physical Examination
Common physical examination findings of non-Hodgkin lymphoma include fever, pruritus, petechiae, chest tenderness, abdominal tenderness, hepatomegaly, splenomegaly, peripheral lymphadenopathy, seizures, and central lymphadenopathy.

## Laboratory Tests
Laboratory tests for non-Hodgkin lymphoma include complete blood count (CBC), blood chemistry studies, HIV blood test, and hepatitis B blood test.

## Chest X Ray
On chest x ray, non-Hodgkin lymphoma is characterized by nodules and pleural effusion.

## CT
Chest, abdomen, and pelvis CT scan may be helpful in the diagnosis of non-Hodgkin lymphoma.

## MRI
MRI may be helpful in the diagnosis of non-Hodgkin lymphoma.

## Ultrasound
On ultrasound, non-Hodgkin lymphoma is characterized by hepatomegaly and  splenomegaly.

## Biopsy
Lymph node or extra nodal tissue biopsy is diagnostic of non-Hodgkin lymphoma.

## Other Imaging Findings
PET and bone scan may be helpful in the diagnosis of non-Hodgkin lymphoma.

## Other Diagnostic Studies
Other diagnostic studies for the diagnosis of non-Hodgkin lymphoma include bone marrow aspiration, bone marrow biopsy, and lumbar puncture.

# Treatment

## Medical Therapy
The predominant therapy for non-Hodgkin lymphoma is chemotherapy. Adjunctive radiation, immunotherapy, and stem cell transplantation may be required.

## Surgery
Surgical intervention is not recommended for the management of non-Hodgkin lymphoma.