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| ==Overview== | | ==[[Monoclonal gammopathy of undetermined significance overview|Overview]]== |
| '''Monoclonal gammopathy of undetermined significance''' (MGUS, ''unknown'' or ''uncertain'' may be substituted for ''undetermined'') or '''benign monoclonal gammopathy''' is a condition in which a low or non-quantifiable level of a [[monoclonal]] [[paraprotein]] is detected in the blood by means of [[protein electrophoresis]]. In addition, some patients develop a [[polyneuropathy]] (damage to peripheral nerves) or other problems related to the secreted antibody. MGUS is distinct from [[multiple myeloma]], as described below.
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| ==Diagnosis== | | ==[[Monoclonal gammopathy of undetermined significance historical perspective|Historical Perspective]]== |
| Patients may be diagnosed with MGUS if they fulfill the following three criteria:<ref>{{cite journal | author =International Myeloma Working Group | title = Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: a report of the International Myeloma Working Group. | journal = Br J Haematol | volume = 121 | issue = 5 | pages = 749-57 | year = 2003 | id = PMID 12780789}}</ref>
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| | ==[[Monoclonal gammopathy of undetermined significance classification|Classification]]== |
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| | ==[[Monoclonal gammopathy of undetermined significance pathophysiology|Pathophysiology]]== |
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| | ==[[Monoclonal gammopathy of undetermined significance causes|Causes]]== |
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| | ==[[Monoclonal gammopathy of undetermined significance differential diagnosis|Differentiating Monoclonal gammopathy of undetermined significance from other Diseases]]== |
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| | ==[[Monoclonal gammopathy of undetermined significance epidemiology and demographics|Epidemiology and Demographics]]== |
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| #A monoclonal paraprotein band less than 3 g/dl;
| | ==[[Monoclonal gammopathy of undetermined significance risk factors|Risk Factors]]== |
| #[[Plasma cell]]s less than 10% on [[bone marrow examination]]; and
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| #No evidence of bone lesions, [[anemia]], [[hypercalcemia]], or [[renal insufficiency]] related to the paraprotein.
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| ==Differential diagnosis==
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| Several other illnesses can present with a monoclonal gammopathy, and the monoclonal protein may be the first discovery before a formal diagnosis is made:
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| * [[Multiple myeloma]]
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| * [[AIDS]]
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| * [[Chronic lymphocytic leukemia]]
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| * [[Non-Hodgkin Lymphoma]], particularly [[Splenic marginal zone lymphoma]]<ref>{{cite journal |author=Murakami H, Irisawa H, Saitoh T, Matsushima T, Tamura J, Sawamura M, Karasawa M, Hosomura Y, Kojima M |title=Immunological abnormalities in splenic marginal zone cell lymphoma |journal=Am. J. Hematol. |volume=56 |issue=3 |pages=173-8 |year=1997 |pmid=9371530}}</ref> and Lymphoplasmocytic lymphoma
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| * [[Hepatitis C]]
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| * [[Connective tissue disease]] such as [[lupus]]<ref>{{cite journal |author=Larking-Pettigrew M, Ranich T, Kelly R |title=Rapid onset monoclonal gammopathy in cutaneous lupus erythematosus: interference with complement C3 and C4 measurement |journal=Immunol. Invest. |volume=28 |issue=4 |pages=269-76 |year=1999 |pmid=10454004}}</ref>
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| * Immunosuppression following organ tranplantation
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| * [[Waldenström macroglobulinemia]]
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| * [[Guillain-Barre syndrome]]<ref>{{cite journal |author=Czaplinski A, Steck A |title=Immune mediated neuropathies--an update on therapeutic strategies |journal=J. Neurol. |volume=251 |issue=2 |pages=127-37 |year=2004 |pmid=14991345}}</ref>
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| ==Pathology==
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| Pathologically, the lesion in MGUS is in fact very similar to that in multiple myeloma. There is a predominance of [[Clone_(B-cell biology)|clonal]] [[plasma cell]]s in the [[bone marrow]] with an abnormal [[immunophenotype]] ([[CD38]]+ [[CD56]]+ [[CD19]]−) mixed in with cells of a normal phenotype (CD38+ CD56− CD19+);<ref>{{cite journal | author = Zhan F, Hardin J, Kordsmeier B, Bumm K, Zheng M, Tian E, Sanderson R, Yang Y, Wilson C, Zangari M, Anaissie E, Morris C, Muwalla F, van Rhee F, Fassas A, Crowley J, Tricot G, Barlogie B, Shaughnessy J | title = Global gene expression profiling of multiple myeloma, monoclonal gammopathy of undetermined significance, and normal bone marrow plasma cells. | journal = Blood | volume = 99 | issue = 5 | pages = 1745-57 | year = 2002 | id = PMID 11861292 | url=http://www.bloodjournal.org/cgi/content/full/99/5/1745}}</ref><ref>{{cite journal | author = Magrangeas F, Nasser V, Avet-Loiseau H, Loriod B, Decaux O, Granjeaud S, Bertucci F, Birnbaum D, Nguyen C, Harousseau J, Bataille R, Houlgatte R, Minvielle S | title = Gene expression profiling of multiple myeloma reveals molecular portraits in relation to the pathogenesis of the disease. | journal = Blood | volume = 101 | issue = 12 | pages = 4998-5006 | year = 2003 | id = PMID 12623842 | url=http://www.bloodjournal.org/cgi/content/full/101/12/4998}}</ref> in MGUS, more than 3% of the clonal plasma cells have the normal phenotype, whereas in multiple myeloma, less than 3% of the cells have the normal phenotype.<ref>{{cite journal | author = Ocqueteau M, Orfao A, Almeida J, Bladé J, González M, García-Sanz R, López-Berges C, Moro M, Hernández J, Escribano L, Caballero D, Rozman M, San Miguel J | title = Immunophenotypic characterization of plasma cells from monoclonal gammopathy of undetermined significance patients. Implications for the differential diagnosis between MGUS and multiple myeloma. | journal = Am J Pathol | volume = 152 | issue = 6 | pages = 1655-65 | year = 1998 | id = PMID 9626070}}</ref> What causes MGUS to transform into multiple myeloma is as yet unknown.
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| ==Prognosis==
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| MGUS may be considered a pre-malignant condition, given the possibility of transformation into multiple myeloma. However, because the condition tends to occur in the elderly, and because the rate of progression is slow, only a small proportion of people with MGUS go on to develop a [[haematological malignancy]]. In patients with MGUS, although the actuarial risk of myeloma at 25 years of follow-up is 30%, the actual risk (when competing causes of death are taken into account) is only 11%.<ref>{{cite journal | author = Bladé J | title = Clinical practice. Monoclonal gammopathy of undetermined significance. | journal = N Engl J Med | volume = 355 | issue = 26 | pages = 2765-70 | year = 2006 | id = PMID 17192542 [http://content.nejm.org/cgi/content/short/355/26/2765 Abstract]}}</ref>
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| The annual risk of progressing to multiple myeloma is around 1–2% a year. Kyle ''et al'' studied the prevalence of myeloma in a population-wide cohort in Olmsted County, Minnesota. They found that the prevalence of MGUS was 3.2% in people above 50, with a slight male predominance (4.0% vs. 2.7%). Prevalence increased with age: of people over 70 up to 5.3% had MGUS, while in the over-85 age group the prevalence was 7.5%. In the majority of cases (63.5%), the paraprotein level was <1 g/dl, while only a very small group had levels over 2 g/dl.<ref name="Kyle">{{cite journal | author=Kyle RA, Therneau TM, Rajkumar SV, Larson DR, Plevak MF, Offord JR, Dispenzieri A, Katzmann JA, Melton LJ 3rd. | title=Prevalence of monoclonal gammopathy of undetermined significance | journal=N Engl J Med | year=2006 | month=28 December | volume=354 | pages=1362-9 | id=PMID 16571879}}</ref>
| | ==[[Monoclonal gammopathy of undetermined significance screening|Screening]]== |
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| In addition to multiple myeloma, MGUS may also progress to [[Waldenström's macroglobulinemia]], primary [[amyloidosis]], [[B-cell lymphoma]], or [[chronic lymphocytic leukemia]].
| | ==[[Monoclonal gammopathy of undetermined significance natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| ==Annual review== | | ==Diagnosis== |
| | [[Monoclonal gammopathy of undetermined significance history and symptoms| History and Symptoms]] | [[Monoclonal gammopathy of undetermined significance physical examination | Physical Examination]] |[[Monoclonal gammopathy of undetermined significance laboratory findings|Laboratory Findings]] | [[Monoclonal gammopathy of undetermined significance chest x ray|Chest X Ray]] | [[Monoclonal gammopathy of undetermined significanceCT|CT]] | [[Monoclonal gammopathy of undetermined significance MRI|MRI]] | [[Monoclonal gammopathy of undetermined significanceultrasound|Ultrasound]] | [[Monoclonal gammopathy of undetermined significance other imaging findings|Other Imaging Findings]] | [[Monoclonal gammopathy of undetermined significance other diagnostic studies|Other Diagnostic Studies]] |
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| The [[protein electrophoresis]] test should be repeated annually, and if there is any concern for a rise in the level of monoclonal protein, then prompt referral to a [[haematologist]] is required. The haematologist, when first evaluating a case of MGUS, will usually perform a [[skeletal survey]] (X-rays of the proximal skeleton), check the blood for [[hypercalcemia]] and deterioration in [[renal function]], check the urine for [[Bence-Jones]] protein and perform a [[bone marrow biopsy]]. If none of these tests are abnormal, a patient with MGUS is followed up once every 6 months to a year with a blood test (serum protein electrophoresis).
| | ==Treatment== |
| | [[Monoclonal gammopathy of undetermined significance medical therapy|Medical Therapy]] | [[Monoclonal gammopathy of undetermined significance surgery|Surgery]] | [[Monoclonal gammopathy of undetermined significance primary prevention|Primary Prevention]] | [[Monoclonal gammopathy of undetermined significance secondary prevention|Secondary Prevention]] | [[Monoclonal gammopathy of undetermined significance cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Monoclonal gammopathy of undetermined significance future or investigational therapies|Future or Investigational Therapies]] |
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| | ==Case Studies== |
| | [[Monoclonal gammopathy of undetermined significance case study one|Case#1]] |
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| ==References== | | ==References== |
| <div class="references-small"><references/></div> | | <div class="references-small"><references/></div> |
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| [[pl:Gammapatia monoklonalna o nieokreślonym znaczeniu]] | | [[pl:Gammapatia monoklonalna o nieokreślonym znaczeniu]] |