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Multiple myeloma

Multiple myeloma (MM), also known as plasma cell myeloma, is a cancer of plasma cells, a type of white blood cell which normally produces antibodies. Often, no symptoms are noticed initially. As it progresses, bone pain, bleeding, frequent infections, and anemia may occur. Complications may include amyloidosis.Bone marrow aspirate showing the histologic correlate of multiple myeloma under the microscope, H&E stainPlasmacytoma, H&E stainMicrograph showing myeloma cast nephropathy in a kidney biopsy: Hyaline casts are PAS positive (dark pink/red - right of image). Myelomatous casts are PAS negative (pale pink - left of image), PAS stain.Atypical plasma cell infiltrate with both Russell (cytoplasmic) and Dutcher (nuclear) bodies (H&E, 50x)X-ray of the forearm, with lytic lesionsSkull X-ray showing multiple lucencies due to multiple myelomaPathological fracture of the lumbar spine due to multiple myelomaA CT of the brain revealed a lytic lesion in the left temporal bone (right side of image), and petrous temporal bones involving the mastoid segment of the facial nerve canal. Red arrows: lesion; green arrow: normal contralateral facial nerve canal. The lesions are consistent with a myeloma deposit.CT scan of the lower vertebral column in a man with multiple myeloma, showing multiple osteoblastic lesions: These are more radiodense (brighter in this image) than the surrounding cancellous bone, in contrast to osteolytic lesions, which are less radiodense.Femur with multiple myeloma lesionsSame femur before myeloma lesions for comparisonHumerus with multiple myeloma lesionsSame humerus before, with just subtle lesions Multiple myeloma (MM), also known as plasma cell myeloma, is a cancer of plasma cells, a type of white blood cell which normally produces antibodies. Often, no symptoms are noticed initially. As it progresses, bone pain, bleeding, frequent infections, and anemia may occur. Complications may include amyloidosis. The cause of multiple myeloma is unknown. Risk factors include obesity, radiation exposure, family history, and certain chemicals. Multiple myeloma may develop from monoclonal gammopathy of undetermined significance that progresses to smoldering multiple myeloma. The abnormal plasma cells produce abnormal antibodies, which can cause kidney problems and overly thick blood. The plasma cells can also form a mass in the bone marrow or soft tissue. When one tumor is present, it is called a plasmacytoma; more than one is called multiple myeloma. Multiple myeloma is diagnosed based on blood or urine tests finding abnormal antibodies, bone marrow biopsy finding cancerous plasma cells, and medical imaging finding bone lesions. Another common finding is high blood calcium levels. Multiple myeloma is considered treatable, but generally incurable. Remissions may be brought about with steroids, chemotherapy, targeted therapy, and stem cell transplant. Bisphosphonates and radiation therapy are sometimes used to reduce pain from bone lesions. Globally, multiple myeloma affected 488,000 people and resulted in 101,100 deaths in 2015. In the United States, it develops in 6.5 per 100,000 people per year and 0.7% of people are affected at some point in their lives. It usually occurs around the age of 61 and is more common in men than women. It is uncommon before the age of 40. Without treatment, typical survival is seven months. With current treatments, survival is usually 4–5 years. The five-year survival rate is about 49%. The word myeloma is from the Greek myelo- meaning 'marrow' and -oma meaning 'tumor'. Because many organs can be affected by myeloma, the symptoms and signs vary greatly. A mnemonic sometimes used to remember some of the common symptoms of multiple myeloma is CRAB: C = calcium (elevated), R = renal failure, A = anemia, B = bone lesions. Myeloma has many other possible symptoms, including opportunistic infections (e.g., pneumonia) and weight loss. Bone pain affects almost 70% of patients and is the most common symptom. Myeloma bone pain usually involves the spine and ribs, and worsens with activity. Persistent, localized pain may indicate a pathological bone fracture. Involvement of the vertebrae may lead to spinal cord compression or kyphosis. Myeloma bone disease is due to the overexpression of receptor activator for nuclear factor κ B ligand (RANKL) by bone marrow stroma. RANKL activates osteoclasts, which resorb bone. The resultant bone lesions are lytic (cause breakdown) in nature, and are best seen in plain radiographs, which may show 'punched-out' resorptive lesions (including the 'raindrop' appearance of the skull on radiography). The breakdown of bone also leads to the release of calcium ions into the blood, leading to hypercalcemia and its associated symptoms. The anemia found in myeloma is usually normocytic and normochromic. It results from the replacement of normal bone marrow by infiltrating tumor cells and inhibition of normal red blood cell production (hematopoiesis) by cytokines. Impaired kidney function may develop, either acutely or chronically, and with any degree of severity. The most common cause of kidney failure in multiple myeloma is due to proteins secreted by the malignant cells. Myeloma cells produce monoclonal proteins of varying types, most commonly immunoglobulins (antibodies) and free light chains, resulting in abnormally high levels of these proteins in the blood. Depending on the size of these proteins, they may be excreted through the kidneys. Kidneys can be damaged by the effects of proteins or light chains. Increased bone resorption leads to hypercalcemia and causes nephrocalcinosis, thereby contributing to the kidney failure. Amyloidosis is a distant third in the causation. Patients with amyloidosis have high levels of amyloid protein that can be excreted through the kidneys and cause damage to the kidneys and other organs.

[ "Pathology", "Immunology", "Diabetes mellitus", "Cancer research", "Internal medicine", "light chain lambda", "Triclonal gammopathy", "Bence Jones protein", "Plasma cell leukemia", "Plasma cell infiltration" ]
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