Plasmacytoma is a plasma cell dyscrasia in which a

plasma cell Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B cells and secrete large quantities of proteins called antibodies in response to being presented specific substances ca ...

tumour A neoplasm () is a type of abnormal and excessive growth of tissue (biology), tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tiss ...

grows within

soft tissue Soft tissue connective tissue, connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, Adipose tissue, fat, fibrous tissue, Lymphatic vessel, lymph and blood vessels, fasciae, and synovial membranes.� ...

or within the

axial skeleton The axial skeleton is the core part of the endoskeleton made of the bones of the head and trunk of vertebrates. In the human skeleton, it consists of 80 bones and is composed of the skull (28 bones, including the cranium, mandible and the midd ...

. The International Myeloma Working Group lists three types: solitary plasmacytoma of bone (SPB); extramedullary plasmacytoma (EP), and multiple plasmacytomas that are either primary or recurrent. The most common of these is SPB, accounting for 3–5% of all plasma cell malignancies. SPBs occur as lytic lesions within the axial skeleton and extramedullary plasmacytomas most often occur in the

upper respiratory tract The respiratory tract is the subdivision of the respiratory system involved with the process of conducting air to the alveoli for the purposes of gas exchange in mammals. The respiratory tract is lined with respiratory epithelium as respiratory ...

(85%), but can occur in any soft tissue. Approximately half of all cases produce

paraproteinemia Monoclonal gammopathy, also known as paraproteinemia, is the presence of excessive amounts of myeloma protein or monoclonal gamma globulin in the blood. It is usually due to an underlying immunoproliferative disorder or hematologic neoplasms, espe ...

. SPBs and extramedullary plasmacytomas are mostly treated with

radiotherapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a treatment using ionizing radiation, generally provided as part of cancer therapy to either kill or control the growth of malignant cells. It is normally delivered by a linear particle ...

, but surgery is used in some cases of extramedullary plasmacytoma. The skeletal forms frequently progress to

multiple myeloma Multiple myeloma (MM), also known as plasma cell myeloma and simply myeloma, is a cancer of plasma cells, a type of white blood cell that normally produces antibody, antibodies. Often, no symptoms are noticed initially. As it progresses, bone ...

over the course of 2–4 years. Due to their cellular similarity, plasmacytomas have to be differentiated from

. For SPB and extramedullary plasmacytoma the distinction is the presence of only one lesion (either in bone or soft tissue), normal

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It i ...

(<5% plasma cells), normal

skeletal survey A skeletal survey (also called a bone survey) is a series of X-rays of all the bones in the body, or at least the axial skeleton and the large cortical bones. A very common use is the diagnosis of multiple myeloma, where tumour deposits appear a ...

, absent or low paraprotein and no end organ damage.

Signs and symptoms

For SPB the most common presenting symptom is that of pain in the affected bone.

Back pain Back pain (Latin: ''dorsalgia'') is pain felt in the back. It may be classified as neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area ...

and other consequences of the bone lesion may occur such as

spinal cord compression Spinal cord compression is a form of myelopathy in which the spinal cord is compressed. Causes can be bone fragments from a vertebral fracture, a tumor, abscess, ruptured intervertebral disc or other lesion. When acute it can cause a medical eme ...

or pathological fracture. Around 85% of extramedullary plasmacytoma presents within the

mucosa A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

, causing possible symptoms such as

epistaxis A nosebleed, also known as epistaxis, is an instance of bleeding from the nose. Blood can flow down into the stomach, and cause nausea and vomiting. In more severe cases, blood may come out of both nostrils. Rarely, bleeding may be so significan ...

, rhinorrhoea and nasal obstruction. In some tissues it may be found as a palpable mass.

Diagnosis

Serum protein electrophoresis normal and paraprotein

The diagnosis of plasmacytoma uses a diverse range of interdisciplinary techniques including

serum protein electrophoresis Serum protein electrophoresis (SPEP or SPE) is a laboratory test that examines specific proteins in the blood called globulins. The most common indications for a serum protein electrophoresis test are to diagnose or monitor multiple myeloma, a ...

bone marrow biopsy Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called trephine biopsy) and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number of condit ...

, urine analysis for

Bence Jones protein Bence Jones protein is a monoclonal globulin protein or immunoglobulin light chain found in the urine, with a molecular weight of 22–24 kDa. Detection of Bence Jones protein may be suggestive of multiple myeloma, or Waldenström's macroglob ...

and

complete blood count A complete blood count (CBC), also known as a full blood count (FBC) or full haemogram (FHG), is a set of medical laboratory tests that provide cytometry, information about the cells in a person's blood. The CBC indicates the counts of white blo ...

, plain film radiography,

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

and PET-CT. Serum protein electrophoresis separates the proteins in the liquid part of the blood (serum), allowing the analysis of antibodies. Normal blood serum contains a range of antibodies and are said to be polyclonal, whereas serum from a person with plasmacytoma may show a monoclonal spike. This is due to an outgrowth of a single type of plasma cell that forms the plasmacytoma and produces a single type of antibody. The plasma cells are said to be monoclonal and the excessively produced antibody is known as monoclonal protein or

paraprotein A myeloma protein is an abnormal antibody (immunoglobulin) or (more often) a fragment thereof, such as an immunoglobulin light chain, that is produced in excess by an abnormal monoclonal proliferation of plasma cells, typically in multiple mye ...

Paraprotein A myeloma protein is an abnormal antibody (immunoglobulin) or (more often) a fragment thereof, such as an immunoglobulin light chain, that is produced in excess by an abnormal monoclonal proliferation of plasma cells, typically in multiple mye ...

s are present in 60% of SPB and less than 25% of extramedullary plasmacytoma. Bone marrow biopsies are performed to ensure the disease is localised; and in SPB or extramedullary plasmacytoma there will not be an increase of monoclonal plasma cells. Tissue biopsies of SPB and extramedullary plasmacytoma are used to assess the

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

of the plasma cells. Histological analyses can be performed on these biopsies to see what

cluster of differentiation The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophe ...

(CD) markers are present and to assess monoclonality of the cells. CD markers can aid in the distinction of extramedullary plasmacytoma from lymphomas.

Skeletal survey A skeletal survey (also called a bone survey) is a series of X-rays of all the bones in the body, or at least the axial skeleton and the large cortical bones. A very common use is the diagnosis of multiple myeloma, where tumour deposits appear a ...

s are used to ensure there are no other primary tumors within the

. MRI can be used to assess tumor status and may be advantageous in detecting primary tumors that are not detected by plain film radiography. PET-CT may also be beneficial in detecting extramedullary tumours in individuals diagnosed with SPB. CT imaging may be better than plain film radiography for assessing bone damage. An important distinction to be made is that a true plasmacytoma is present and not a systemic plasma cell disorder, such as

. The difference between plasmacytoma and multiple myeloma is that plasmacytoma lacks increased

blood calcium Calcium ions (Ca2+) contribute to the physiology and biochemistry of organisms' cell (biology), cells. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, i ...

, decreased kidney function, too few red blood cells in the bloodstream, and multiple bone lesions (collectively termed CRAB).

Classification

Plasmacytoma is a

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

s. The cells are identical to those seen in

, but they form discrete masses of cells in the skeleton (solitary plasmacytoma of bone; SPB) or in soft tissues (extramedullary plasmacytoma; EP). They do not present with

systemic disease A systemic disease is one that affects a number of Organ (anatomy), organs and Tissue (biology), tissues, or affects the Human body, body as a whole. It differs from a localized disease, which is a disease affecting only part of the body (e.g., ...

, which would classify them as another systemic plasma cell disorder. The International Myeloma Working Group (IMWG) has published criteria for the diagnosis of plasmacytomas. They recognise three distinct entities: SPB, extramedullary plasmacytoma and multiple solitary plasmacytomas (+/- recurrent). The proposed criteria for SPB is the presence of a single bone lesion, normal bone marrow (less than 5% plasma cells), small or no paraprotein, no related organ involvement/damage and a normal

(other than the single bone lesion). The criteria for extramedullary plasmacytoma are the same but the tumor is located in soft tissue. No bone lesions should be present. Criteria for multiple solitary plasmacytomas (+/- recurrent) are the same except either multiple solitary bone or soft tissue lesions must be present. They may occur as multiple primary tumors or as a recurrence from a previous plasmacytoma.

Association with the Epstein–Barr virus

Rarely, the

Epstein–Barr virus The Epstein–Barr virus (EBV), also known as human herpesvirus 4 (HHV-4), is one of the nine known Herpesviridae#Human herpesvirus types, human herpesvirus types in the Herpesviridae, herpes family, and is one of the most common viruses in ...

(EBV) is associated with multiple myeloma and plasmacytomas, particularly in individuals who have an

immunodeficiency Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that aff ...

due to e.g.

HIV/AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...

organ transplantation Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be trans ...

, or a chronic inflammatory condition such as

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

. EBV-positive multiple myeloma and plasmacytoma are classified together by the World Health Organization (2016) as Epstein–Barr virus-associated lymphoproliferative diseases and termed Epstein–Barr virus-associated plasma cell myeloma. EBV-positivity is more common in plasmacytoma than multiple myeloma. The tissues involved in EBV+ plasmacytoma typically show foci of EBV+ cells with the appearance of rapidly proliferating immature or poorly differentiated plasma cells. These cells express products of EBV genes such as EBER1 and EBER2. EBV-positive plasmacytoma(s) is more likely to progress to multiple myeloma than EBV-negative plasmacytoma(s) suggesting that the virus may play a role in the progression of plasmacytoma to multiple myeloma.

Treatment

Radiotherapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a treatment using ionizing radiation, generally provided as part of cancer therapy to either kill or control the growth of malignant cells. It is normally delivered by a linear particle ...

is the main choice of treatment for both SPB and extramedullary plasmacytoma, and local control rates of >80% can be achieved. This form of treatment can be used with curative intent because plasmacytoma is a radiosensitive tumor.

Surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

is an option for extramedullary plasmacytoma, but for cosmetic reasons it is generally used when the lesion is not present within the head and neck region. Another option is the possible combination of radiotherapy with anti-

treatment. In a study that included 68 patients, a group of 8 patients who were treated with radio- and chemotherapy (with or without surgery) were less likey to have a relapse of plasmacytoma, progress to multiple myeloma, or die compared with patients who were treated with radiotherapy and/or surgery alone rogression free survival (PFS), overall median: not reached vs. 48.0 months; respectively Concerning that study, a large prospective trial is needed to evaluate the impact of adding systemic anti-myeloma treatment to local radiotherapy.

Prognosis

Most cases of SPB progress to

within 2–4 years of diagnosis, but the overall median survival for SPB is 7–12 years. 30–50% of extramedullary plasmacytoma cases progress to multiple myeloma with a median time of 1.5–2.5 years. 15–45% of SPB and 50–65% of extramedullary plasmacytoma are disease free after 10 years.

Epidemiology

Plasmacytomas are a rare form of cancer. SPB is the most common form of the disease and accounts for 3-5% of all plasma cell malignancies. The median age at diagnosis for all plasmacytomas is 55. Both SPB and extramedullary plasmacytoma are more prevalent in males; with a 2:1 male to female ratio for SPB and a 3:1 ratio for extramedullary plasmacytoma.

Terminology

There can be some ambiguity when using the word. "Plasmacytoma" is sometimes equated with " plasma cell dyscrasia" or "solitary myeloma". It is often used as part of the phrase "solitary plasmacytoma". or as part of the phrase "extramedullary plasmacytoma". In this context, "extramedullary" means outside of the

References

External links

Overview
at

National Cancer Institute The National Cancer Institute (NCI) coordinates the United States National Cancer Program and is part of the National Institutes of Health (NIH), which is one of eleven agencies that are part of the U.S. Department of Health and Human Services. ...

{{Lymphoid malignancy Hematologic malignant neoplasms Lymphoid-related cutaneous conditions Epstein–Barr virus–associated diseases