What Is Plasma Cell Dyscrasia?

Plasmacytoma includes extramedullary plasmacytoma (EMP), solitary plasmacytoma of bone, multiple myeloma (MM), and plasmablastoma. EMP, also known as primary soft tissue plasmacytoma, refers to plasma cell tumors that occur in soft tissues other than bone marrow hematopoietic tissue without multiple or solitary bone marrow. It is a relatively rare type of malignant monoclonal plasma cell disease. 1.9% to 2.8% of all plasma cell tumors. At present, there are problems of inadequate experience and inconsistent opinions in diagnosis and treatment.

Basic Information

English name

plasmocytoma

Visiting department

Oncology

Common causes

Systemic tumor of bone marrow origin

Common symptoms

Bone pain, weakness, weight loss, or mild anemia

Causes of plasmacytoma

Plasmacytoma is a primary and systemic malignant tumor originating in the bone marrow. It is derived from B lymphocytes and has the property of differentiating into plasma cells.

Clinical manifestations of plasmacytoma

Plasmacytoma is a systemic tumor that originates in the bone marrow and eventually affects most bones throughout the body, especially in the adult part where there is red bone marrow. These areas are the cavernous bones of the trunk, the metaphysis of the skull and long bones, especially the cavernous bones around the hip and shoulder joints. Plasma dissemination of plasmacytomas does not occur at the same time, nor is it consistent. Plasma cell tumors with a single lesion limited to a single bone segment at the beginning of the disease are not uncommon. This plasma cell tumor is a single plasma cell. Although a single lesion can be maintained for several years, it is a single plasma cell that persists in a single lesion. Rarely, bones can spread and cause death. The most common site of a single plasmacytoma is the spine (one or two vertebrae), followed by the trunk bone and the proximal femur. Symptoms include mild bone pain, physical weakness, weight loss, or mild anemia. Patients often complain of lower back pain and can extend to the chest. Spinal pain is often aggravated by exercise, paravertebral muscles can contract, and tapping the spinous processes can induce pain. In some cases of low back pain, the tumor tissue of multiple myeloma can compress nerve roots and cause radiation pain in the sciatic nerve or foot. With mild trauma or no obvious cause, spinal pain can become very severe, which is a sign of a pathological vertebral fracture. When the vertebral body is widely invaded, it can be paralyzed due to progressive or sudden spinal cord compression, with or without vertebral compression fractures. In the advanced stage, there may be swelling of superficial bones (ribs, sternum, clavicle), progressive weight loss, anemia, fever, hypertensive nitrogen, bleeding tendency, hypercalcemia and hyperuricemia, extra bone tumors, and starch Giant tongue caused by degeneration, renal failure in a few cases, severe cases can cause uremia.

Plasma cell tumor examination

Bone marrow smear

In the early stage of plasmacytoma, when the diagnosis is not clear, bone marrow smear can often confirm the diagnosis, but a negative does not rule out the possibility of plasmacytoma. If the smear has 3% plasma cells, the possibility of plasmacytoma should be suspected; if there is 10% plasma, plasmacytoma is very likely, but it can also be diffused by liver infection or cancerous bone metastases Plasma cells increase in the bone marrow around sexual or metastatic foci; if the percentage of plasma cells is higher, up to 70%, and there are atypical plasma cells beside typical plasma cells, a plasma cell tumor can be diagnosed. The more the plasmacytoma progresses, the higher the positive rate of cytology.

Serum protein

Serum globulin was increased in most cases, and the albumin / globulin ratio was inverted. Even though total globulin did not increase, immunoelectrophoresis showed a narrow and sharp peak in the alpha or gamma globulin band region, which was due to the increase in monoclonal immunoglobulin. In a few cases, serum electrophoresis was not manifested, while urine electrophoresis was manifested.

3.Bence-Jones proteinuria

Urine protein electrophoresis and immunoprotein electrophoresis are used to detect, which is more sensitive than the traditional heating urine test. The positive rate of Bence-Jones proteinuria is not high, and it can be seen in plasmacytoma (K chain or L chain) cases that secrete light chain globulin.

4. Hypercalcemia

Myeloma hyperplasia can often cause diffuse bone resorption, leading to elevated blood calcium. Hyperuricemia and azotemia are common. Hyperuricemia is caused by strong nucleic acid metabolism and can occur in all patients with hyperproliferative bone marrow. Hyperazoemia is caused by renal damage to myeloma.

5. Anemia

White blood cells are generally unchanged, but in rare cases there can be a significant increase in white blood cell counts and even a large number of plasma cells. Such cases are considered plasma cell leukemias.

6.X-ray view

There is a latent period of imaging findings, and the extent of the lesions' dissection is anatomical and disproportionate to the image. Even though the tumor tissue has invaded the bone marrow cavity, bone trabeculae and cortical bone are not significantly absorbed, and the imaging findings are negative. Myeloma tumor tissue can destroy bone tissue and show obvious porous changes. The image shows extensive osteoporosis and thinning of cortical bone, especially in the early stage of the lesion and tumor invasion of the spine. During the progression of myeloma, tumor tissue can not only extensively invade the medullary cavity, but also form disseminated tumor nodules. The tumor nodules that have just formed are small in size and can grow and fuse in the future. These pathological changes determine plasma cells. The typical imaging manifestations of tumors are micro-worm-eaten, round point osteolysis, foamy after fusion of osteolysis areas, and extensive osteolysis in late stage. There is no hardened edge around a typical osteolytic cavity. At the same time, the tumor tissue can erode the cortical bone inside the bone, making it thin, and some areas can disappear.

Differential diagnosis of plasmacytoma

In the early stage of plasmacytoma, when the diagnosis is not clear, bone marrow smear can often confirm the diagnosis, but it can also be diffuse due to liver infection or cancerous bone metastases.

Clinically, if patients over 40 years of age suffer from skeletal pain or diffuse low back pain, fatigue, paleness, and mild weight loss, the possibility of myeloma should be suspected. Bone marrow aspiration results can only show undifferentiated atypical components. If only bone marrow aspiration results, they can be misdiagnosed as lymphoma.

Plasma cell tumor treatment

For the treatment of plasmacytoma, most scholars believe that radiotherapy alone can achieve satisfactory results, so radiotherapy should be preferred.

If the lesion is located in soft tissue, those who have more limited surgery and can be completely removed can be treated with surgery alone. However, complete resection is often difficult for most operations, especially when the lesions are located in the head and neck, and the surrounding important organs are dense. Radical surgery may have an impact on function and beauty. Therefore, in fact, most operations are relatively limited and require postoperative radiotherapy. Experience has shown that combined surgery and radiation therapy can also achieve satisfactory results. Chemotherapy is necessary when the disease progresses and causes symptoms, and some authors have suggested that patients with adverse prognostic factors (such as poor differentiation, local destruction, obvious infiltration, etc.) can be treated with adjuvant chemotherapy to slow the disease progression. Chemotherapy regimens often use regimens similar to those for multiple myeloma and non-Hodgkin's lymphoma, namely MP regimen (melphalan, prednisone), M2 regimen (vincristine, carmustine, melphalan, Cyclophosphamide, prednisone) or CHOP protocol (cyclophosphamide, doxorubicin, vincristine, prednisone).