

Understanding idiopathic multicentric
Castleman disease (iMCD)
How iMCD Is Diagnosed
Getting to an iMCD diagnosis starts with ruling out other conditions
Because iMCD can look like cancer, infectious diseases, or autoimmune conditions, your healthcare team will evaluate you or your loved one for more than 15 other conditions before reaching a diagnosis. Explore some of the conditions that iMCD can look like to the right.


My doctor [did] all kinds of tests—CT scan, ultrasound, and of course, blood tests.
Tracking symptoms may help you reach an accurate diagnosis sooner
The road to diagnosis can be long. That’s why it’s important for you to report every symptom to your healthcare team.
You’ll typically start by meeting with your primary care physician who may refer you to a specialist. Click below to learn about some of the doctors you might meet and tests you might have to complete.
This is not a complete list of all the doctors you might meet.
- A primary care physician can conduct blood tests/imaging and refer you to a specialist
- An infectious disease expert can rule out infections
- A rheumatologist can rule out autoimmune conditions
- A nephrologist can check to ensure that your kidneys are functioning properly
- A hematologist-oncologist can rule out cancerous conditions
- A surgeon can remove a swollen lymph node
- A pathologist can examine a swollen lymph node
- Physical examination of swollen lymph nodes, enlarged organs, and fluid accumulation
- Blood tests to look for signs of infection, autoimmune conditions, and kidney damage
- An x-ray, a positron emission tomography (PET) scan, or a computed tomography (CT) scan will reveal the presence of multiple swollen lymph nodes and enlarged organs
- An incisional biopsy, also known as a fine-needle aspiration or core biopsy, removes only a portion of the lymph node for examination. Results may be inconclusive with this type of biopsy
- An excisional biopsy removes the entire lymph node and is a more effective way to diagnose iMCD
Getting an accurate diagnosis for a rare disease like iMCD is never easy. That’s why it’s important to work with your doctors and remain persistent throughout the diagnostic journey.
Our discussion guide is a helpful tool for conversations with your doctors.

iMCD is treatable
Siltuximab is a preferred treatment for iMCD by the National Comprehensive Cancer Network (NCCN).
IL-6, interleukin-6; R.A.R.E., Recordati Access, Resources, and Engagement.
What is SYLVANT?
SYLVANT® (siltuximab) is a prescription medicine used to treat people with multicentric Castleman’s disease (MCD) who do not have human immunodeficiency virus (HIV) and human herpesvirus-8 (HHV-8) infection. It is not known if SYLVANT is safe and effective in children.
IMPORTANT SAFETY INFORMATION
Who should not receive SYLVANT?
Do not receive SYLVANT if you have had a severe allergic reaction to siltuximab or any of the ingredients in SYLVANT. See the Patient Information leaflet for SYLVANT for a complete list of ingredients.
Before starting SYLVANT, tell your healthcare provider (HCP) about all of your medical conditions, including if you:
- have an infection. You should not receive SYLVANT if you have a severe infection.
- have had a recent vaccination or are scheduled to receive any vaccinations. You should not receive a live vaccine during your treatment with SYLVANT.
- have or have had any stomach or bowel (intestine) problems, such as diverticulitis or ulcers. Tell your healthcare provider if you have pain in your stomach area.
- are pregnant or plan to become pregnant. It is not known if SYLVANT will harm your unborn baby. You should not become pregnant while receiving treatment with SYLVANT. Females who are able to become pregnant should use effective birth control during treatment with SYLVANT and for 3 months after stopping treatment.
- are breastfeeding or plan to breastfeed. It is not known if SYLVANT passes into your breast milk. You and your healthcare provider should decide if you will take SYLVANT or breastfeed. You should not do both.Tell your healthcare provider about all the medicines you take, including any prescription and over-the-counter medicines, vitamins, and herbal supplements.
What are the possible side effects of SYLVANT?
SYLVANT may cause serious side effects, including:
- Infections. SYLVANT may lower your ability to fight infections. Tell your healthcare provider right away if you have any signs or symptoms of an infection during treatment with SYLVANT.
- Infusion and allergic reactions. If you have an infusion or allergic reaction while receiving SYLVANT, your healthcare provider will stop your infusion and treat your reaction. If you have a severe infusion or allergic reaction, your healthcare provider may stop your treatment completely. Tell your healthcare provider or get medical help right away if you have any of these symptoms during or after your infusion of SYLVANT: back pain, chest pain or tightness, nausea and vomiting, flushing, redness, irregular heart beat (palpitations), trouble breathing, wheezing, dizziness or light-headedness, swelling of the lips, skin rash, headache, or itching.
- The most common side effects of SYLVANT include rash, itching, upper respiratory tract infection, swelling, weight gain, and increased blood level of uric acid.
These are not all the possible side effects of SYLVANT. Call your HCP for medical advice about side effects. You are encouraged to report side effects of prescription drugs to the FDA. Call 1-800-FDA-1088 or visit www.fda.gov/medwatch.
SYLVANT® (siltuximab) for injection, for intravenous use, is available as 100 mg or 400 mg of lyophilized powder in a single-dose vial.
Please see full Prescribing Information, including Patient Information.