What is Blastic Plasmacytoid Dendritic Cell Neoplasm?

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, highly aggressive type of blood cancer that is identified by skin issues, problems with the bone marrow, and the spread of abnormal blood cells throughout the body. The understanding and naming of BPDCN has grown over many years. Originally, in 1995, it was referred to as acute agranular CD4+ natural killer (NK) cell leukemia. However, in 2008, it was found that the original cancerous cell was the plasmacytoid dendritic cell and the World Health Organization (WHO) started to use the term BPDCN to group together specific types of blood cancers.

What Causes Blastic Plasmacytoid Dendritic Cell Neoplasm?

There are no known environmental or genetic factors that make a person more likely to develop BPDCN, a type of blood cancer. It can occur on its own or alongside other blood-related cancers. A history of other blood cancers, like myelodysplastic syndrome, chronic myeloid leukemia, chronic myelomonocytic leukemia, and acute myeloid leukemia, has been seen in 10% to 20% of patients who are diagnosed with BPDCN. But, it’s still unclear how or if these conditions are biologically linked to BPDCN.

Normally, plasmacytoid dendritic cells, which are part of the lymphoid system (the part of the body that fights infection), are not commonly found in the skin. However, they can move to the skin in response to infections or inflammation. But, when scientists looked for any signs of bacterial or viral infections that could have triggered BPDCN, they didn’t find anything in the skin or bone marrow.

Risk Factors and Frequency for Blastic Plasmacytoid Dendritic Cell Neoplasm

BPDCN is a rare blood cancer, and its exact frequency is not known. It’s challenging to estimate the number of cases due to changes in its names and the fact that, until 2008, there was no official way to diagnose it. Despite this, it’s responsible for around 0.7% of skin cancers that originate in the skin itself. However, this could be an underestimation, as BPDCN can also occur without affecting the skin.

  • BPDCN affects people from all racial backgrounds and geographic areas.
  • It can occur in patients of all ages, but it’s most common in older adults, with the average age of diagnosis between 65 and 67 years old.
  • It’s slightly more common in males. For every female with BPDCN, there are about 2.5 males.

Signs and Symptoms of Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a type of blood cancer. Its most noticeable feature is skin lesions, seen in about 90% of patients. Sometimes, the disease can only be found in these skin lesions, which can still be there even if the disease is not present in the bone marrow. Although skin lesions are the most common symptom, BPDCN can also affect other deeper organs and it can occasionally appear without any skin involvement at all.

The skin lesions caused by BPDCN vary; they can look like brown or purple bruises, plaques, or nodules and may appear alone or in clusters. There’s a belief that the skin might act as a shield against the disease’s spread and certain factors produced by the tumor cells could play a role in causing the skin symptoms of BPDCN.

Furthermore, BPDCN can also lead to other signs and symptoms due to it affecting various organs. These symptoms can include:

  • Decreased blood cell count (cytopenias)
  • Swollen lymph nodes (lymphadenopathy)
  • Enlarged liver (hepatomegaly)
  • Enlarged spleen (splenomegaly)

The disease can also affect the mucous membrane, tonsils, cavities in the face, lungs, eyes, and the central nervous system (the brain and spinal cord), as reported in some documented cases.

Testing for Blastic Plasmacytoid Dendritic Cell Neoplasm

If your doctor suspects you have skin cancer, such as blastic plasmacytoid dendritic cell neoplasm, they might take a small sample of your skin. This process is known as a skin biopsy. By examining this sample (a task done using routine histology and immunohistochemistry, or lab techniques that help identify cells and tissues), your doctor can better understand whether your skin lesions are cancerous or not.

However, sometimes, this cancer can be present even without visible skin lesions. Thus, if you have poorly differentiated leukemia (a type of blood cancer that is hard to classify due to the abnormal cells not having clear features) and an uncertain immunophenotype (the types and amount of proteins produced by the cells that help identify them), it is still possible that you might have this specific type of skin cancer. On the other hand, patients with leukemic dissemination (spread of leukemia cells to other organs in your body) should also undergo a bone marrow biopsy. This type of biopsy helps check for the presence of other blood cancers.

Immunohistochemistry and another lab technique called flow cytometry can help confirm the diagnosis. Blastic plasmacytoid dendritic cell neoplasm cells usually show positive results for lots of proteins including CD4, CD56, CD123, BDCA-2/CD303, TCF4, TCL1, and SPIB. They also often exhibit a protein expression called Terminal deoxynucleotidyl transferase (TdT) in 40% of cases. Other proteins such as CD68, CD7, and CD33 are also frequently present. However, the cancer cells do not usually show expression of other proteins like Epstein-Barr virus-encoded RNA, CD19, CD20, CD79a, CD3, CD5, myeloperoxidase, CD117, lysozyme, CD13, CD16, and CD34.

Before starting treatment, your doctor will need to run a series of tests. This includes complete blood counts, liver and kidney function tests, and tests for lactate dehydrogenase (an enzyme that could indicate tissue damage), hepatitis B, and HIV. If a stem cell transplant is needed, a process known as human leukocyte antigen (HLA) typing will be conducted. Your doctor will also examine your blood under a microscope and conduct a unilateral bone marrow biopsy and aspirate to check if the cancer has spread. A CT scan will also be done to check for lymph nodes enlargement and enlargement of the liver and spleen (known as hepatosplenomegaly). If you have any neurological signs or symptoms, your doctor will conduct appropriate imaging studies and examine the fluid that surrounds your brain and spinal cord.

Treatment Options for Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare disease that can be treated in several ways. These treatments can include traditional chemotherapy, a newer drug known as tagraxofusp, and stem cell transplantation.

There’s no established treatment for BPDCN, but in the past, intensive chemotherapy used for other illnesses like acute myeloid leukemias and acute lymphoid leukemia/lymphoma has been used. But, the response rates were not quite satisfactory, with half the patients surviving less than nine months in one study. Treatment options like HyperCVAD or CHOP regimens which borrowed from the acute lymphoid leukemia/lymphoma resulted in better survival time and remission rates compared to acute myeloid leukemia regimen, but the relapse rate was higher.

Scientists have developed tagraxofusp, a drug that targets a specific protein (CD123) found in high amounts in BPDCN. Tagraxofusp has been approved by the Food and Drug Administration (FDA) in the USA for the treatment of BPDCN in adults and children over 2 years old. In a study, tagraxofusp led to the disappearance of the disease in about 72% of patients, and the survival rates at 18 months and 24 months were 59% and 52%, respectively. Common side effects were related to liver function and low protein levels in the blood. Still, its response rate was comparable to HyperCVAD and CHOP chemotherapy regimens.

Stem cell transplant has also been successful in treating BPDCN, but doctors are still figuring out the best timing and type of transplant. Patients who received an allogeneic stem cell transplant (using stem cells from a donor) tended to live longer than those who did not get a transplant. Stem cell transplant is currently seen as the only way to have a long-lasting disappearance of the disease.

In children diagnosed with BPDCN, it is recommended to start with tagraxofusp or acute lymphoid leukemia/lymphoma-like treatment and observation rather than a stem cell transplant, due to the risk of significant side effects. However, if the child is under 2 years old, only the acute lymphoid leukemia/lymphoma-like treatment is advised because tagraxofusp is not approved for use in children under 2 years old.

For BPDCN that has returned or didn’t respond to the initial treatment, the best approach is still unclear. Available options might include a repeat of the original treatment or trying different chemotherapy drugs. Clinical trials may also give patients access to novel treatments.

When doctors are dealing with a condition called BPDCN, they need to be able to tell it apart from something known as mature plasmacytoid dendritic cell proliferation (MPDCP). While both involve the growth of certain cells, MPDCP is different because these cells are not harmful and are mostly seen in patients with other conditions like AML, chronic myelomonocytic leukemia, and less so with myelodysplastic syndrome and myeloproliferative neoplasms. MPDCP is found in the skin, lymph nodes, and bone marrow, but you can tell them apart from BPDCN by the way their cells look when studied under a microscope.

BPDCN cells look more like ‘blast’ cells, which are immature cells. Other diseases that have these ‘blast’ cells might also be confused with BPDCN, so doctors need to be careful to get the diagnosis right. Because the treatment will depend on the correct diagnosis, doctors have to consider several other conditions that can look like BPDCN.

  • Acute myeloid leukemia
  • B-ALL
  • T-ALL
  • Natural killer/T-cell lymphoma nasal type
  • Adult T-cell leukemia/lymphoma
  • Anaplastic large cell lymphoma
  • Angiosarcoma
  • Kaposi sarcoma
  • Merkel cell carcinoma
  • Malignant melanoma

A combination of a thorough patient history, careful look at the cells, and studies to identify the type of cell (immunohistochemical findings) can help doctors arrive at the correct diagnosis.

What to expect with Blastic Plasmacytoid Dendritic Cell Neoplasm

BPDCN is a type of cancer formed from immature cells, and it is considered aggressive, meaning it grows and spreads quickly. If it is not treated early, it can be deadly. Different studies have shown that the usual survival rates are between 12 to 27 months, but survival tends to be longer in children or those where the cancer only affects the skin. A treatment called Hematopoietic stem-cell transplantation (HSCT), which involves replacing unhealthy blood-forming cells with healthy ones, is the best way to increase one’s chances of long-term survival.

Survival rates are often more favorable in younger patients. According to a study involving 25 pediatric patients—whose results were combined with those of earlier patient reports—about 72% of them survived after receiving chemotherapy. The study also found that the rate of cancer-free survival was 64%, with a follow-up period ranging from 9 months to 13 years.

Another factor that affects how BPDCN progesses is the presence of a protein called CXCL12, which is associated with the transformation of skin lesions to a cancerous state. Moreover, the stage of cell maturity at the tumor site also seems to correlate with how responsive the cells are to treatment, with immature cells typically more receptive to treatment than mature cells.

The appearance of skin lesions—whether they appear as individual lumps, bruises, or widespread redness—does not significantly affect the likelihood of successful treatment according to clinical studies.

Possible Complications When Diagnosed with Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasms are a form of cancer that can bring about complications. Without the proper treatment, this disease can be deadly. Even with treatment, the illness can come back, so it’s important to remain under close clinical observation.

The treatments, which can include chemotherapy and HSCT (bone marrow or stem cell transplants), can also have side effects. Some known side effects from these treatments are:

  • Decrease in all types of blood cells, known as pancytopenia
  • Liver function issues
  • Kidney problems
  • Increased chance of infections
  • Risk of death

A drug named tagraxofusp, which is used to treat this type of cancer, can have a rare but serious side effect known as capillary leak syndrome (CLS). CLS usually occurs about 5 days into treatment, and it’s marked by:

  • Low levels of albumin in the blood, known as hypoalbuminemia
  • Gaining weight
  • Swelling due to excess body fluids, known as edema
  • Low blood pressure, known as hypotension

In the first phases of drug trials, 19% of patients got CLS, and 2 patients died from it. Also, having lower levels of albumin in the blood at the start of the treatment increases the likelihood of subsequently developing CLS.

Preventing Blastic Plasmacytoid Dendritic Cell Neoplasm

Patients should be well advised about the course of a cancer known as blastic plasmacytoid dendritic cell neoplasm. They need to understand the different treatment paths available, the possible complications, and the possibility of the cancer coming back. It’s also vital that they understand how the disease might progress and that following the treatment plan accurately is extremely important. Should the treatment have undesirable side effects, the patient should quickly get in touch with their cancer specialist for a complete check-up. If the cancer returns, patients may be able to join clinical trials of new treatments.

The information about birth control and breastfeeding should be clearly shared with female patients. Patients should be told to monitor their weight daily using the same scales for consistency. Women who may become pregnant while receiving a specific treatment called tagraxofusp should make sure that they are using a reliable method of birth control during their treatment and for a week after the last treatment has ended. If a female patient becomes pregnant, she should get in touch with her physician to search for other treatment options. In terms of breastfeeding, it’s suggested that a gap of at least 48 hours is left after the last dose before breastfeeding again. Although studies with pregnant women have not been done, there may be a possibility of harm to the unborn baby.

Frequently asked questions

Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) is a rare and highly aggressive type of blood cancer that is characterized by skin issues, bone marrow problems, and the spread of abnormal blood cells throughout the body.

BPDCN is a rare blood cancer, and its exact frequency is not known.

The signs and symptoms of Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) can vary, but they may include: - Skin lesions: Skin lesions are the most noticeable feature of BPDCN, seen in about 90% of patients. These lesions can appear as brown or purple bruises, plaques, or nodules. They may appear alone or in clusters. - Decreased blood cell count (cytopenias): BPDCN can lead to a decrease in the number of blood cells, which can cause symptoms such as fatigue, weakness, and increased susceptibility to infections. - Swollen lymph nodes (lymphadenopathy): BPDCN can cause the lymph nodes to become enlarged and swollen. - Enlarged liver (hepatomegaly): In some cases, BPDCN can lead to an enlargement of the liver. - Enlarged spleen (splenomegaly): BPDCN can also cause the spleen to become enlarged. - Involvement of other organs: BPDCN can affect various organs in the body, including the mucous membrane, tonsils, cavities in the face, lungs, eyes, and the central nervous system (the brain and spinal cord). However, these cases are less common. It's important to note that not all patients with BPDCN will experience all of these symptoms, and the severity of the symptoms can vary from person to person. If you are experiencing any concerning symptoms, it's important to consult with a healthcare professional for an accurate diagnosis and appropriate treatment.

There are no known environmental or genetic factors that make a person more likely to develop Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN).

The doctor needs to rule out the following conditions when diagnosing Blastic Plasmacytoid Dendritic Cell Neoplasm: - Acute myeloid leukemia - B-ALL - T-ALL - Natural killer/T-cell lymphoma nasal type - Adult T-cell leukemia/lymphoma - Anaplastic large cell lymphoma - Angiosarcoma - Kaposi sarcoma - Merkel cell carcinoma - Malignant melanoma

The types of tests needed for Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) include: 1. Skin biopsy: A small sample of the skin is taken to examine whether the skin lesions are cancerous or not. 2. Bone marrow biopsy: This biopsy helps check for the presence of other blood cancers, especially in patients with leukemic dissemination. 3. Immunohistochemistry: This lab technique helps confirm the diagnosis by identifying specific proteins expressed by BPDCN cells. 4. Flow cytometry: Another lab technique that can assist in confirming the diagnosis by analyzing the types and amount of proteins produced by the cells. 5. Complete blood counts: These tests provide information about the blood cell counts and can help monitor the progression of the disease. 6. Liver and kidney function tests: These tests assess the functioning of the liver and kidneys, which can be affected by BPDCN. 7. Lactate dehydrogenase test: This test measures the levels of an enzyme that could indicate tissue damage. 8. Tests for hepatitis B and HIV: These tests are conducted to check for the presence of these infections, which can impact treatment decisions. 9. Human leukocyte antigen (HLA) typing: If a stem cell transplant is needed, this test is conducted to match the donor's cells with the patient's cells. 10. CT scan: This imaging test is done to check for lymph node enlargement and enlargement of the liver and spleen. 11. Neurological imaging studies: If there are neurological signs or symptoms, appropriate imaging studies are conducted to assess the brain and spinal cord. 12. Observation and monitoring: Regular observation and monitoring of the disease are essential to track its progression and response to treatment.

Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) can be treated in several ways. Treatment options include traditional chemotherapy, a newer drug called tagraxofusp, and stem cell transplantation. Traditional chemotherapy used for other illnesses like acute myeloid leukemias and acute lymphoid leukemia/lymphoma has been used in the past, but the response rates were not satisfactory. Tagraxofusp, a drug that targets a specific protein (CD123) found in high amounts in BPDCN, has been approved by the FDA for the treatment of BPDCN in adults and children over 2 years old. Stem cell transplantation has also been successful in treating BPDCN, with allogeneic stem cell transplant leading to longer survival. The best approach for BPDCN that has returned or didn't respond to initial treatment is still unclear, but options may include repeating the original treatment or trying different chemotherapy drugs, and clinical trials may offer access to novel treatments.

The side effects when treating Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) can include: - Decrease in all types of blood cells (pancytopenia) - Liver function issues - Kidney problems - Increased chance of infections - Risk of death Specifically, the drug tagraxofusp, which is used to treat BPDCN, can have a rare but serious side effect known as capillary leak syndrome (CLS). Symptoms of CLS include low levels of albumin in the blood (hypoalbuminemia), weight gain, swelling due to excess body fluids (edema), and low blood pressure (hypotension). In the first phases of drug trials, 19% of patients experienced CLS, and 2 patients died from it. Lower levels of albumin in the blood at the start of treatment increase the likelihood of subsequently developing CLS.

The prognosis for Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) is generally poor, with survival rates ranging from 12 to 27 months. However, survival tends to be longer in children or when the cancer only affects the skin. Hematopoietic stem-cell transplantation (HSCT) is the best treatment option to increase long-term survival chances.

An oncologist or a hematologist-oncologist.

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