What is Castleman Disease?
Castleman disease encompasses a group of rare disorders characterized by the abnormal enlargement of lymph nodes and a wide array of symptoms. First identified in 1956 by Dr. Benjamin Castleman, these diseases have since been categorized into distinct types based on their clinical presentation and underlying causes. While Castleman disease can affect individuals of any age and gender, it is most commonly diagnosed in adults during midlife.
The disorder primarily affects the lymphatic system, which plays a crucial role in immune function by filtering pathogens and maintaining fluid balance. The lymph nodes can become enlarged due to the accumulation of abnormal immune cells and inflammatory processes, leading to significant complications if left untreated.
Types of Castleman Disease
- Unicentric Castleman Disease (UCD): The most common form, UCD, typically involves a single enlarged lymph node, often located in the neck or chest. Many individuals with UCD may not experience noticeable symptoms, and the condition is often discovered incidentally during imaging studies.
- Multicentric Castleman Disease (MCD):
MCD is more complex, involving multiple enlarged lymph nodes along with systemic symptoms. It can further be categorized into three types:
HHV-8-Associated MCD: This type is linked to human herpes virus type 8 (HHV-8) and is more prevalent among individuals with compromised immune systems, such as those living with HIV.
Idiopathic MCD: The cause of this type is unknown and is characterized by its lack of association with HHV-8.
POEMS-Associated MCD: This variant is associated with POEMS syndrome, a rare condition that impacts the nerves and various organs.
A lesser-known subtype, oligocentric Castleman disease, involves two to three enlarged lymph nodes without fulfilling the criteria for MCD.
Symptoms
General Symptoms:
- Fever
- Unintentional weight loss
- Fatigue
- Night sweats
- Swelling in various body parts
- Enlarged liver or spleen
Blood-Related Symptoms:
- Low red blood cell count (anemia)
- Variations in platelet counts
- Elevated creatinine levels indicating potential kidney issues
- Abnormal levels of blood proteins, including immunoglobulins and albumin
Severe Symptoms in iMCD-TAFRO:
This serious form includes:
- Low platelet count (thrombocytopenia)
- Significant swelling and fluid accumulation (anasarca)
- Fever and elevated inflammatory markers
- Organ enlargement (organomegaly)
Causes and Risk Factors
The exact causes of UCD and idiopathic MCD remain unclear. However, HHV-8-associated MCD is linked to individuals with weakened immune systems, particularly those with HIV. Castleman disease can affect individuals of any age or gender, although it is most commonly diagnosed in midlife.
Complications
While many individuals with UCD experience favorable outcomes post-surgery, they may face a heightened risk of developing paraneoplastic pemphigus, a rare autoimmune condition characterized by painful blisters.
MCD can progress rapidly, leading to life-threatening organ dysfunction. Those with HHV-8-positive MCD may experience severe complications, including infections and organ failure, particularly if they are also HIV positive.
Diagnosis
Diagnosis involves a thorough medical history review and physical examination, followed by several tests:
Blood and Urine Tests: These help rule out other conditions and identify anemia or abnormalities in blood proteins.
Imaging Tests: CT scans or PET scans are used to visualize enlarged lymph nodes and assess organ involvement.
Lymph Node Biopsy: This essential procedure involves removing a tissue sample from an enlarged lymph node for laboratory examination, helping to confirm the diagnosis and rule out other disorders, such as lymphoma.
Treatment
- Unicentric Castleman Disease: Surgical removal of the affected lymph node is the primary treatment for UCD. In cases where surgery is not feasible, treatments akin to those for MCD may be employed. Follow-up imaging and tests are crucial to monitor for recurrence.
- Multicentric Castleman Disease:
HHV-8-Positive MCD: Initial treatment often involves therapies targeting HHV-8 and may include antivirals or chemotherapies to reduce excess immune cell activity.
- Idiopathic MCD:
Treatment typically starts with th*rapies aimed at reducing inflammation and controlling symptoms. In critically ill patients, corticosteroids may be administered to manage inflammation, along with possible chemoth*rapy.
Long-term management often requires ongoing assessment and adjustment of treatment strategies based on individual responses.
Castleman disease is a complex group of disorders with varied presentations and treatment needs. Timely diagnosis and appropriate management are essential to improve outcomes and quality of life for affected individuals. Ongoing research aims to enhance understanding and treatment options for this rare condition.