World Castleman Disease Day Date in the current year: July 23, 2025

Castleman disease (CD) is an umbrella term for a group of rare disorders involving enlarged lymph nodes. Lymph nodes play a critical role in the immune system by functioning as biological filters for foreign particles, including cancer cells. In individuals with Castleman disease, the immune system overproduces cytokines and other proteins normally produced in immune responses to infection or cancer. This results in swollen lymph nodes and other symptoms.

There are two main types of CD. Unicentric Castleman disease (UCD) involves one or more enlarged lymph nodes in a single region of the body. Multicentric Castleman disease (MCD) involves enlarged lymph nodes in multiple parts of the body. MCD, in turn, has three subtypes:

• POEMS-associated multicentric Castleman disease (POEMS-MCD)
• HHV-8-associated multicentric Castleman disease (HHV-8+MCD)
• HHV-8-negative/idiopathic multicentric Castleman disease (iMCD)

Both UCD and idiopathic MCD have no known causes or risk factors. HHV-8-associated MCD is caused by human herpesvirus 8 (HHV-8), which can also cause Kaposi’s sarcoma, primary effusion lymphoma, and KSHV inflammatory cytokine syndrome. Only a small percentage of infected individuals develop Castleman disease, and this is typically those who already have a compromised immune system. POEMS-MCD is associated with cancerous cells in patients with POEMS syndrome, a rare paraneoplastic syndrome.

In UCD, enlarged lymph nodes are often the only symptom; some patients experience inflammatory symptoms, such as fever or fatigue. MCD tends to have more severe symptoms, which can include flu-like symptoms, unexplained weight loss, an enlarged spleen or liver, peripheral neuropathy (numbness in the hands and feet), kidney problems, fatigue, weakness, swelling, and skin rashes. Since these symptoms overlap with those of many other conditions, laboratory tests are needed to confirm the diagnosis. In CD, there are specific microscopic changes to the lymph nodes.

Each type of CD has specific treatment options. In patients with UCD, enlarged lymph nodes are typically surgically removed if possible. HHV-8-associated MCD is usually treated with rituximab, and iMCD is usually treated with a combination of anti-IL-6 agents and steroids. Patients with POEMS-MCD are treated for POEMS syndrome.

On July 23, the entire Castleman disease community, including patients, their families and loved ones, physicians, and researchers, observes World Castleman Disease Day. The day’s main goals are to raise public awareness of the disease, support those living with it, honor those who have died from it, and promote further research.

On World Castleman Disease Day, the Castleman Disease Collaborative Network (CDCN) raises funds to accelerate critical research into finding a cure. The CDCN encourages donations of $7.23, $72.30, or $723 to reflect the date of the awareness day (07/23). Other ways to participate in World CD Day include raising awareness on social media (don’t forget to use the hashtags #WorldCastlemanDiseaseDay and #WorldCDDay) and wearing blue, the color of CD awareness, to start conversations.