Castleman disease, also known as angiofollicular lymph node hyperplasia, is a rare disorder characterized by the abnormal growth of lymphatic cells. It was first described by Dr. Benjamin Castleman in the 1950s, hence the name.

Castleman disease can occur in two forms: unicentric Castleman disease (UCD) and multicentric Castleman disease (MCD). UCD affects a single lymph node or a group of lymph nodes, while MCD involves multiple lymph nodes and can affect various organs in the body.

Prevalence of Castleman Disease

Castleman disease is considered extremely rare, with an estimated prevalence of less than one in 100,000 individuals worldwide.

However, due to the lack of awareness and potential misdiagnosis, the exact prevalence of Castleman disease may be higher than reported. It affects people of all ages, genders, and ethnic backgrounds, although it is more commonly diagnosed in individuals between the ages of 20 and 50.

Unicentric Castleman Disease

Unicentric Castleman disease is the more common form of Castleman disease, accounting for about 80% of all cases.

The exact cause of UCD is unknown, but it is believed to be related to an abnormal response of the immune system to an infection or inflammation. UCD typically presents as a single enlarged lymph node, most commonly in the chest or abdomen. Symptoms may vary depending on the location of the affected lymph node but can include fatigue, fever, night sweats, and weight loss.

Diagnosis and Treatment of Unicentric Castleman Disease

Diagnosing UCD often involves a combination of imaging tests, such as CT scans or MRIs, and a biopsy of the affected lymph node. The biopsy helps confirm the presence of lymphatic cell abnormalities.

Treatment for UCD usually involves surgical removal of the affected lymph node. In some cases, radiation therapy or medication may be recommended. The prognosis for UCD is generally excellent, and most individuals can expect a full recovery after treatment.

Multicentric Castleman Disease

Multicentric Castleman disease is a more complex and aggressive form of Castleman disease. It is characterized by the presence of multiple enlarged lymph nodes, which can affect various areas of the body, including the neck, armpits, groin, and abdomen.

Unlike UCD, MCD is associated with chronic inflammation and dysregulation of the immune system. It is often linked to infection with the human herpesvirus 8 (HHV-8) and, less commonly, Epstein-Barr virus (EBV).

Symptoms and Complications of Multicentric Castleman Disease

MCD can cause a wide range of symptoms, including fatigue, night sweats, fever, unintentional weight loss, enlarged liver or spleen, swollen lymph nodes, and neurological abnormalities.

The disease can progress rapidly and lead to severe complications, such as organ failure, anemia, and an increased risk of developing lymphoma or other cancers.

Diagnosis and Treatment of Multicentric Castleman Disease

Diagnosing MCD can be challenging due to its rarity and varied clinical presentation. It may require a combination of imaging tests, blood tests to detect viral infections, and a lymph node biopsy.

To differentiate MCD from other conditions, such as lymphoma, a thorough evaluation is necessary. Treatment for MCD aims to control the symptoms, minimize complications, and manage the underlying viral infection. Options may include chemotherapy, immunotherapy, antiviral medications, and targeted therapies.

Rare Subtypes of Castleman Disease

In addition to the two main forms of Castleman disease, there are several rare subtypes with distinct characteristics. These include hyaline vascular Castleman disease, plasma cell Castleman disease, and mixed multicentric Castleman disease.

Hyaline vascular Castleman disease is the most common subtype and is associated with solitary enlarged lymph nodes. Plasma cell Castleman disease is less common and involves the overproduction of plasma cells in the lymph nodes. Mixed multicentric Castleman disease combines characteristics of both unicentric and multicentric forms.

Prognosis and Research

The prognosis for Castleman disease varies depending on the subtype and overall health of the individual.

Most individuals with unicentric Castleman disease have an excellent prognosis, while the prognosis for multicentric Castleman disease is more guarded due to the potential for severe complications. Ongoing research is focused on understanding the underlying causes of Castleman disease, improving diagnostic methods, and developing targeted therapies to provide better treatment options for individuals affected by this rare disorder.

Conclusion

Castleman disease is a rare disorder characterized by abnormal growth of lymphatic cells. It can manifest as unicentric or multicentric forms, each with distinct clinical features and treatment approaches.

Although Castleman disease is considered rare, its exact prevalence may be underestimated due to potential misdiagnosis. Early and accurate diagnosis is crucial for effective management and improved prognosis. Ongoing research is essential to further enhance our understanding and treatment of this rare disease.