Castleman disease encompasses a group of rare disorders characterized by abnormal growth within the lymph nodes. These conditions stem from a hyperactive immune system that, instead of calming after fighting off a threat, remains overstimulated. This persistent overactivity leads to chronic inflammation and the enlargement of lymph nodes. Understanding the specific type of Castleman disease is important because symptoms, treatment options, and overall outlook can differ significantly.
What is Castleman Disease?
Castleman disease is a rare lymphoproliferative disorder involving the uncontrolled growth of immune cells in the lymphatic system. This abnormal cellular activity causes lymph nodes to swell and undergo tissue changes. The immune system continues to produce inflammatory proteins, leading to ongoing inflammation that can affect various organs.
The disease is broadly categorized into two main types: unicentric Castleman disease (UCD) and multicentric Castleman disease (MCD). UCD affects a single lymph node or a group of lymph nodes in one body region, such as the chest or neck. This form is generally less severe and accounts for about three-quarters of all cases.
Multicentric Castleman disease involves enlarged lymph nodes in multiple body areas, often with widespread inflammatory symptoms. MCD is further classified into two primary subtypes: idiopathic MCD (iMCD) and HHV-8-associated MCD. Idiopathic MCD has no known cause, while HHV-8-associated MCD is linked to human herpesvirus-8 infection, particularly in immunocompromised or HIV positive individuals.
Identifying the Symptoms
Symptoms vary considerably depending on whether an individual has the unicentric or multicentric form. For unicentric Castleman disease, the most common sign is an enlarged lymph node felt as a lump under the skin, often in the neck, collarbone, armpit, or groin. These enlarged lymph nodes usually do not cause discomfort, but can sometimes lead to pressure, pain, or difficulty breathing if they press on nearby organs. About half of UCD patients experience no symptoms.
Multicentric Castleman disease typically presents with a broader range of systemic symptoms. These include flu-like symptoms such as persistent fever, night sweats, and unexplained weight loss. Individuals might also experience fatigue, swelling in various body parts due to fluid retention, and an enlarged spleen or liver. The non-specific nature of these symptoms can make diagnosis challenging, as they often overlap with those of more common illnesses.
Navigating Diagnosis and Treatment
Diagnosing Castleman disease requires a comprehensive evaluation, as its symptoms can mimic other conditions. The definitive diagnosis relies on a lymph node biopsy, where a tissue sample from an enlarged lymph node is removed and examined under a microscope for characteristic features. This biopsy is crucial to confirm Castleman disease and rule out other disorders, such as lymphoma.
Healthcare providers utilize various tests to assess the disease’s extent and guide treatment. Imaging tests, such as CT and PET scans, help locate enlarged lymph nodes and identify other affected organs. Blood and urine tests check for abnormal blood cell counts, signs of inflammation, protein changes, and viruses like HHV-8, which is associated with a specific type of MCD.
Treatment approaches are highly specific to the type diagnosed. For unicentric Castleman disease, surgical removal of the affected lymph node is generally the primary and often curative treatment. If surgery is not feasible due to the lymph node’s location or size, or if symptoms persist, medical therapies like anti-IL-6 therapy, rituximab, or radiation therapy may be considered to shrink the node or manage symptoms.
Treating multicentric Castleman disease is more complex as it involves multiple lymph node regions. Medical therapies aim to reduce inflammation and control the overgrowth of immune cells. For idiopathic MCD, siltuximab, an anti-interleukin-6 (IL-6) therapy, is often the first-line treatment, as it targets a protein overproduced in these patients. Corticosteroids may also be used to reduce inflammation and provide symptom relief.
For HHV-8-associated MCD, rituximab is a commonly used therapy. Antiviral drugs are also administered for HHV-8-associated cases, especially if the individual also has HIV. Chemotherapy may be incorporated if other treatments are not effective or in rapidly progressing cases.
Managing Life with Castleman Disease
Living with Castleman disease often involves ongoing management and follow-up care, particularly for the multicentric forms, which are chronic conditions. Regular monitoring by a medical team, including imaging and laboratory tests, tracks disease activity, assesses treatment effectiveness, and detects any potential recurrence.
Individuals may need to manage side effects from ongoing treatments, which can vary depending on the specific medications used. Fatigue is a common challenge, and strategies such as prioritizing rest and engaging in gentle physical activity can be helpful. Building a strong support system, including family, friends, and patient organizations, is beneficial for navigating the emotional and practical aspects of living with a rare disease.
Effective management strategies can significantly improve a person’s quality of life. Remission is possible, but recurrence can occur, emphasizing the importance of consistent medical oversight.