Form Of Idiopathic Inflammatory Myopathy Research Articles

Case series on anti-melanoma differentiation-associated gene 5+ dermatomyositis associated with interstitial lung disease

Dermatomyositis (DM) associated with anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody is a rare autoimmune disease. Anti-MDA5, also known as anti-CADM-140 antibodies. DM affects the skeletal muscle, skin, joints, and lungs and is a form of idiopathic inflammatory myopathy (IIM). All the 5 dermatomyositis MDA5+ positive patients had rapidly progressive interstitial lung disease (RP-ILD). DM is classified into 2 types, classic dermatomyositis (CDM) and clinically amyopathic dermatomyositis (CADM). Anti-MDA5 antibody-positive as RP-ILD without signs of DM or CADM. RP-ILD in patients with CADM associated with antibodies to MDA5 has a high mortality rate. MDA5+ DM is diagnosed by DM rashes (Gottron’s papules or Gottron’s sign and heliotrope rash) and a positive anti-MDA5. RP-ILD includes acute/subacute interstitial pneumonia, which is a progressive deterioration associated with ILD. Immunosuppressives are effective agents for the treatment of anti-MDA5-positive RP-ILD of CADM.

18F-FDG PET/CT and HRCT: a combined tool for risk stratification in idiopathic inflammatory myopathy-associated interstitial lung disease.

Rapidly progressive interstitial lung disease (RP-ILD) is a life-threatening form of idiopathic inflammatory myopathy (IIM)-associated interstitial lung disease (ILD). We aimed to assess the combination of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) and high-resolution computed tomography (HRCT) for the quantification of IIM-ILD activity and risk stratification for RP-ILD. Patients with IIM and undergoing 18F-FDG PET/CT were included in this retrospective study. Pulmonary FDG uptake was assessed using the maximum standardized uptake value (SUVlung) and visual score (PET score). HRCT was evaluated using visual analysis (HRCT score). Multivariable logistic regression was used to identify risk factors for RP-ILD. Seventy-three patients with IIM (17 with RP-ILD, 38 with non-RP-ILD, and 18 without ILD) were included. SUVlung, PET score, and HRCT score were significantly higher in RP-ILD than in non-RP-ILD. Strong positive correlations were observed between SUVlung, PET score, and the HRCT parameters. The area under the curve (AUC) of the PET score to differentiate between RP-ILD and non-RP-ILD (AUC = 0.860) was higher than that of the SUVlung (AUC = 0.802) and HRCT scores (AUC = 0.806). We developed a risk score based on the number of positive risk factors (PET score > 18, HRCT score > 140, and positive anti-melanoma differentiation-associated gene 5 (MDA5) antibody) to differentiate between RP-ILD and non-RP-ILD (AUC = 0.955). Patients with higher risk scores had significantly worse prognoses. 18F-FDG PET/CT is useful for assessing disease activity in patients with IIM-ILD. The combination of PET score, HRCT score, and anti-MDA5 antibody can be used to identify patients at increased risk of RP-ILD and with poor prognoses.

1057 A CASE OF AUTOIMMUNE NECROTISING MYOSITIS

IntroductionAn 88-year-old previously independent lady presented with progressive proximal weakness of all limbs and multiple falls for 10 months. Her swallowing got difficult lately. She lost weight gradually in that duration but denied any other symptoms suggestive of malignancy. PMH—Hypothyroid, Mild cognitive impairment Drg History—Atorvastatin for years. Stopped in this admission.On examination, she showed signs of proximal muscle weakness and areflexia in both upper and lower limbs without muscle tenderness. She had no facial nor eye muscle weakness. Sensory functions were intact. There were no rashes.Investigations CK 2000 TSH 24 Inflammatory markers, white cell counts—non-significant Vitamin D—18 CT-Chest Abdomen Pelvis, CT-colonography—No evidence of malignancy Paraneoplastic antibodies—Negative Anti-OJ and anti-Ro52 Antibodies—positive ENA profile—negative Anti-RNP—equivocal HMG-CoA reductase antibodies (HMCR)—Positive.ProgressPrednisolone was commenced and gradually increased to 60 mg once a day but there is no significant improvement clinically though creatinine kinase level had improved. She was unfortunately infected with COVID-19 infection in the stay which delayed the plan for muscle biopsy and EMG. It affected the plan for Intravenous Immunoglobulins and was later decided to be non-beneficial due to high risks of thromboembolic events and superimposed infections. Steroid was later switched to methotrexate. She was discharged to a rehab unit.ConclusionNecrotising Autoimmune Myopathy is a rare form of idiopathic inflammatory myopathy. Risk factors include statins, cancer, connective tissue diseases, autoimmune diseases, and infections such as HIV2. Diagnosis includes clinical features, serum creatine kinase, HMG CoA reductase antibody (HMGCR-Ab), electromyography, and muscle biopsy. The first-line treatment options are steroids and immunosuppressive agents. Early use of immunoglobulin achieves good outcome. It is still under investigation for the recommended choice for immunosuppressive therapy and the duration of the therapy.

Inflammatory myopathies: an update for neurologists.

Idiopathic inflammatory myopathies (IIM) are a heterogenous group of treatable myopathies. Patients present mainly to the rheumatologist and neurologists, complaining of acute or subacute onset of proximal weakness. Extramuscular manifestations may occur, including involvement of the lungs, skin, and joints. Classically, the diagnosis used to be made based on the creatine kinase level increase, abnormalities in electroneuromyography and presence of inflammatory infiltrates in the muscle biopsy. Recently, the importance of autoantibodies has increased, and now they may be identified in more than half of IIM patients. The continuous clinicoseropathological improvement in IIM knowledge has changed the way we see these patients and how we classify them. In the past, only polymyositis, dermatomyositis and inclusion body myopathy were described. Currently, immune-mediated necrotizing myopathy, overlap myositis and antisynthetase syndrome have been considered the most common forms of IIM in clinical practice, increasing the spectrum of classification. Patients previously considered to have polymyositis, in fact have these other forms of seropositive IIM. In this article, we reviewed the new concepts of classification, a practical way to make the diagnosis and how to plan the treatment of patients suffering from IIM.

Myositis Antibodies and Interstitial Lung Disease.

Interstitial lung disease (ILD) comprises a heterogeneous group of inflammatory and fibrotic conditions, often resulting in progressive lung function decline and increased mortality. Connective tissue disease (CTD) should be considered in all patients with ILD, as distinguishing between CTD-ILD and other forms of fibrotic lung disease has important therapeutic and prognostic implications. The idiopathic inflammatory myopathies (IIM) represent a CTD subtype of growing interest to ILD experts. The expansion and availability of myositis-specific and myositis-associated antibody testing has allowed for improved disease detection and characterization. In this review, we highlight the relationship between myositis antibodies and ILD. Select forms of IIM, such as the antisynthetase syndrome and clinically amyopathic dermatomyositis can present with rapidly progressive ILD, warranting timely disease diagnosis and management. Disease phenotypes, prevalence, laboratory testing, prognosis, and management strategies are described according to select myositis antibodies. Myositis antibodies provide valuable information for clinicians managing patients with ILD. This review aims to increase awareness of their role in disease detection, pathophysiology, and possibly therapeutics.

Muscle shear wave elastography, conventional B mode and power doppler ultrasonography in healthy adults and patients with autoimmune inflammatory myopathies: a pilot cross-sectional study

BackgroundBefore the role of shear wave elastography (SWE) and B mode ultrasound (US) in the diagnosis of different forms of idiopathic inflammatory myopathies (IIM) can be investigated, normative data is required. This study aimed to describe and then compare normative SWE and B mode ultrasound metrics of muscles in healthy controls and patients with IIM.MethodsTwenty nine healthy adult controls and 10 IIM patients (5 with inclusion body myositis and 5 with necrotising autoimmune myopathy) underwent a full clinical examination, laboratory investigations, SWE and US measurements of selected proximal and distal limb muscles. Shear wave speed (SWS) and multiple US domains [echogenicity, fascial thickness, muscle bulk and power Doppler (PD)] were measured in both groups.ResultsIn healthy controls (n = 29; mean age 46.60 ± 16.10; 44.8 % female), age was inversely correlated with SWS at the deltoid (stretch) (Rs. -0.40, p = 0.030) and PD score at the deltoid (rest) (Rs. -0.40, P = 0.032). Those ≥ 50 years old had a lower SWS at the deltoid (stretch) compared to the < 50 year group (2.92 m/s vs. 2.40 m/s, P = 0.032). Age correlated with increased echogenicity in the flexor digitorum profundus (Rs. 0.38, P = 0.045). Females had a smaller muscle bulk in the deltoid (P = 0.022). Body mass index (BMI) was inversely associated with SWS in the deltoid (stretch) (Rs – 0.45, P = 0.026), and positively correlated with echogenicity in the deltoid (Rs. 0.69, P = 0.026). In patients ≥50 years of age, patients with IIM (mean age 61.00 ± 8.18; females 20.0 %) had a higher proportion of abnormal echogenicity scores at the flexor digitorum profundus (FDP) (40.00 % vs. 14.30 %, P = 0.022) and tibialis anterior (TA) (80.00 % vs. 28.60 %, P = 0.004). Fascial thickness was lower in the FDP (0.63mm vs. 0.50mm, p = 0.012) and TA (0.58mm vs. 0.45mm, P = 0.001).ConclusionsOur findings suggest there is scope for US techniques to be useful for diagnostic screening of affected muscles in patients with IIM, especially in those with suspected inclusion body myositis or necrotising autoimmune myopathy. We provide normative data for future studies into SWE and US techniques in skeletal muscle. The differences between IIM patients and controls warrant further study in a broader IIM patient cohort.

Клинические варианты поражения легких при поли- и дерматомиозите

The idiopathic inflammatory myopathies are a group of rare, heterogeneous connective tissue disorders characterized by skeletal muscle inflammation. The four main forms of idiopathic inflammatory myopathies are dermatomyositis, polymyositis, inclusion body myositis, and necrotizing immune-mediated myopathy. Each form of myositis, other than inclusion body myositis, can be associated with damage to many organs, including the lungs, heart, joints, and skin. The most often observed damage to the lung tissue with the development of interstitial lung disease, which occurs with or without myositis. The severity of the course varies from mild to severe, with rapid development of respiratory failure. Interstitial lung disease can be fatal in patients with myositis, therefore, it is necessary to assess the damage to the lung tissue in the early stages of the disease.

The correlation between cardiac and skeletal muscle pathology in animal models of idiopathic inflammatory myopathies.

Idiopathic inflammatory myopathies (IIMs) represent a heterogeneous group of disorders in which skeletal muscle is inappropriately targeted by the immune system. IIMs are characterized by inflammation of muscle and varying degrees of muscle dysfunction. Extra-muscular manifestations may involve heart, skin, joints, lungs, and gastrointestinal tract. Cardiovascular involvement is a feared event because is one of the leading causes of mortality in IIM patients. As the myocardium shares many features with the skeletal muscle, it is supposed that it can be affected by the same inflammatory processes, which take place during the different forms of IIMs. However, the full extent of this link and the mechanisms behind it are still not fully understood. Animal models have greatly improved our understanding of IIM pathomechanisms and have proven to be a useful tool for discovering therapeutic drug targets. Here we report the evidence of heart muscle involvement in different animal models of spontaneous IIMs, assuming a common autoimmune mechanism and presenting them as study models for human pathology.

Role of Myokines in Myositis Pathogenesis and Their Potential to be New Therapeutic Targets in Idiopathic Inflammatory Myopathies.

Idiopathic inflammatory myopathies (IIM) represent a heterogeneous group of autoimmune diseases whose treatment is often a challenge. Many patients, even after immunosuppressive therapy, do not respond to treatment, so new alternatives have been sought for this. Therefore, other signaling pathways that could contribute to the pathogenesis of myositis have been investigated, such as the expression of myokines in skeletal muscle in response to the inflammatory process. In this review, we will refer to these muscle cytokines that are overexpressed or downregulated in skeletal muscle in patients with various forms of IIM, thus being able to contribute to the maintenance of the autoimmune process. Some muscle cytokines, through their antagonistic action, may be a helpful contributor to the disease modulation, and thus, they could represent personalized treatment targets. Here, we consider the main myokines involved in the pathogenesis of myositis, expressing our view on the possibility of using them as potential therapeutic targets: interleukins IL-6, IL-15, and IL-18; chemokines CXCL10, CCL2, CCL3, CCL4, CCL5, and CCL20; myostatin; follistatin; decorin; osteonectin; and insulin-like 6. An interesting topic regarding the complex connection between myokines and noninflammatory pathways implied in IIM has also been briefly described, because it is an important scientific approach to the pathogenesis of IIM and can be a therapeutic alternative to be considered, especially for the patients who do not respond to immunosuppressive treatment.

Idiopathic Inflammatory Myopathies

Myositis is a rare and an extremely heterogeneous autoimmune disease, that causes muscle weakness. Currently, "idiopathic inflammatory myopathies (IIM)" is the preferred umbrella-term used to describe the disease complexity within individuals. IIM include dermatomyositis, polymyositis, inclusion body myositis, autoimmune necrotizing myopathy, overlap myositis and antisynthetase syndrome. Research activity concerning myositis was very intense over the past ten years and led to new diagnostic approach as well as to novel therapeutic strategies. Correct classification is the key for successful management. One single treatment regime for every possible organ involvement in all different forms of IIM is still not existing.

Myositis-Specific Antibodies and Myositis-Associated Antibodies in Patients With Idiopathic Inflammatory Myopathies From the PANLAR Myositis Study Group.

Dermatomyositis (DM) and polymyositis (PM) are forms of idiopathic inflammatory myopathies (IIMs), which are associated with the production of autoantibodies that are useful in the diagnosis and prognosis of the disease. The aim of this study was to determine the frequency of antinuclear autoantibodies (ANAs), myositis-specific autoantibodies (MSAs), and myositis-associated autoantibodies (MAAs) in 6 Latin American countries. Two hundred ten patients with IIM were included in this cross-sectional study from 2014 to 2017: 112 from Mexico, 46 from Colombia, 20 from Peru, 16 from the Dominican Republic, 10 from Argentina, and 6 from Guatemala. Antinuclear autoantibodies were detected by indirect immunofluorescence on HEp-2 cells. MSAs and MAAs were tested by a line immunoassay method. Mann-Whitney U and χ2 tests were used for statistical analysis. Of the 210 IIM patients, 139 (66.2%) had DM, 59 (28%) PM, and 12 (5.7%) juvenile DM. The mean age was 43.5 (6-79 years); 158 (75.2%) were female, and 52 (24.8%) were male. The overall frequency of ANA was 60%. The most frequent patterns were fine speckled (AC-4) (78.3%) and cytoplasmic (AC-19) (6.45%). The most frequent MSA were anti-Mi-2 (38.5%) and anti-Jo-1 (11.9%). Anti-Mi-2 was more frequent in patients from Colombia (40.1%). The MAA more frequent were anti-Ro-52/TRIM21 (17.6%) and anti-PM-Scl75 (7.5%). This is the first study of ANA, MSA, and MAA in patients from 6 countries from the Panamerican League against Rheumatism myositis study group. We observed a general prevalence of 60% of ANA. In relation to MSA and MAA, anti-Mi-2 was the more frequent (38.5%).

Arthritis in Idiopathic Inflammatory Myopathies.

Arthritis is a well-recognized symptom of idiopathic inflammatory myopathies (IIM). We provide a summary of available data regarding the epidemiology, clinical characteristics, and autoantibody associations of joint involvement in various forms of IIM. Arthritis is reported in 18-55% of patients with IIM. It is particularly frequent (20-70%) in those with antisynthetase syndrome (ASS); highest prevalence is associated with anti-Jo-1 positivity. Most common manifestation is non-erosive polyarthritis. X-ray erosions may be found occasionally in ASS, particularly in patients with overlap with rheumatoid arthritis (RA). Arthritis is often present at the time of IIM diagnosis and it may even precede the onset of muscle weakness. Arthritis may in some cases be the main disease manifestation responsible for the disease burden in patients with IIM. Arthritis is a frequent symptom of IIM. Polyarthritis of small joints of the hands is the most frequent clinical manifestation. Arthritis may be the first or dominant symptom in IIM and therefore patients may be initially misdiagnosed as having RA. Particularly in seronegative RA patients with interstitial lung disease or Raynaud's phenomenon, the possibility of IIM should be considered.

Myositis-Related Interstitial Lung Diseases: Diagnostic Features, Treatment, and Complications.

Idiopathic inflammatory myopathies (IIMs) are a group of rare, heterogeneous connective tissue diseases marked by skeletal muscle inflammation. The four main forms of IIMs include dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM), and immune-mediated necrotizing myopathy (IMNM). Anti-synthetase syndrome (ASyS) is a very important classification of the IIM phenotypical spectrum and can be associated with rapidly progressive pulmonary disease. Each form of myositis, except inclusion body myositis, can be associated with multisystem organ involvement including pulmonary, cardiac, arthritis, and skin. The lung in DM, PM and ASyS is the most common extra-muscular organ in IIM with a spectrum ranging from mild to fatal interstitial lung disease (ILD) with or without muscle involvement. Given that there is a subset of myositis patients with rapidly progressive ILD, it is important that rheumatologists in particular assess for lung involvement in all patients with myositis. In recent years, serologic testing for myositis autoantibodies has been more readily available allowing clinicians to order these tests commercially. The evaluation of a patient with myositis not only includes clinical phenotyping but also close observation to tendency for and rapidity of lung progression as well as serologic phenotyping with autoantibodies which can guide the treatment plan and prognosis of patients with ILD. Herein, essential aspects of recognition, diagnosis, monitoring of progression, scope of treatment and IIM-ILD related complications are discussed.

In vivo pathogenicity of IgG from patients with anti-SRP or anti-HMGCR autoantibodies in immune-mediated necrotising myopathy

ObjectivesIn autoimmunity, autoantibodies (aAb) may be simple biomarkers of disease or true pathogenic effectors. A form of idiopathic inflammatory myopathy associated with anti-signal recognition particle (SRP) or anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR)...

Necrotizing autoimmune myopathy: an emerging entity in the spectrum of inflammatory myopathies

Background: Necrotizing autoimmune myopathy is a relatively newly recognized rare form of idiopathic inflammatory myopathy. It presents clinically with symmetrical proximal muscle pain and weakness, associated with a markedly elevated Creatine kinase level. These myopathies are usually immune mediated with a good response to immunotherapy. Case presentation: We present a case of a 32 year old man of Asian descent, having a 6 months history of symmetrical proximal muscle weakness. Patient underwent extensive workup and was diagnosed with Necrotizing autoimmune myopathy. Conclusion: The disease process of Necrotizing autoimmune myopathy is still not completely understood. However, a delay in the diagnosis may lead to potential complications as the disease progresses rapidly.

Profile of Pediatric Idiopathic Inflammatory Myopathies from a Tertiary Care Center of Eastern India.

To report data on Idiopathic inflammatory myopathies (IIM) from eastern India. All IIM patients diagnosed over the last 5 y (2011-2016) were included through a retrospective review of records from the hospital and specialty clinic at Institute of Postgraduate Medical Education & Research (I.P.G.M.E.&R.), Kolkata. Out of the 11 IIM patients, 9 had Juvenile dermatomyositis (JDM) and 2 had overlap myositis (OM) [with systemic lupus erythematosus (SLE) and scleroderma]. The overall sex ratio was M: F=1: 2.6. The mean age at diagnosis was 6.94 y for JDM and 7 y for OM. The mean interval from onset to diagnosis was 5.2 mo. All patients had heliotrope rash and proximal myopathy (n=11,100%). Other findings included Gottron papule (n=7; 64%), arthritis (n=6; 54%), malar rash (n=5; 45%), dysphagia (n=4; 36%), nasal intonation (n=3; 27%), subcutaneous nodule (n=2; 18%), cutaneous sinus (n=1; 9%), calcinosis universalis (n=1; 9%), GI bleed (n=1; 9%). All patients had raised erythrocyte sedimentation rate (ESR), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) while 10 had raised creatine kinase (CK). Three were anti-nuclear-antibody (ANA) positive. Electromyography (EMG) showed proximal myopathy in most cases (n=9; 82%). All patients received corticosteroid. Intravenous immunoglobulin (IVIG) was given to 2 patients. Two received hydroxychloroquine. Cyclophosphamide and azathioprine were given in one each. This study, first reported profile of IIM from eastern India, showed JDM as the commonest form of IIM with a female preponderance. Five children had complete and 2 had partial remission. Two patients of JDM and 1 of OM died. Increased awareness, early referral, prompt diagnosis and treatment might improve the outcome and survival.

Inclusion Body Myositis: What Most Impacts Patients' Lives.

Inclusion body myositis (IBM) is the most common form of idiopathic inflammatory myopathy in adults older than 50 years. Few studies have focused on the functional, physical, and social limitations of this disease. This study identifies pertinent symptoms that impact the health and daily function of patients with IBM. We used semistructured interviews with 10 biopsy-confirmed adults with IBM to identify the psychological, physical, and functional limitations that have the greatest impact on the lives of patients with IBM. Participants with IBM provided 644 direct quotes identifying issues that have the greatest effect on their lives. Two hundred nine individual symptoms and 17 symptomatic themes were identified by patients as having a significant impact on their lives. The symptomatic themes mentioned most frequently involved mobility and ambulation, emotional distress, and activity impairment. Identifying critical issues to patients with IBM is potentially useful for clinicians whose aim is to provide optimal care to patients with IBM.

Childhood Arthritis and Rheumatology Research Alliance Consensus Clinical Treatment Plans for Juvenile Dermatomyositis with Persistent Skin Rash.

Juvenile dermatomyositis (JDM) is the most common form of idiopathic inflammatory myopathy in children. While outcomes are generally thought to be good, persistence of skin rash is a common problem. The goal of this study was to describe the development of clinical treatment plans (CTP) for children with JDM characterized by persistent skin rash despite complete resolution of muscle involvement. The Childhood Arthritis and Rheumatology Research Alliance, a North American consortium of pediatric rheumatologists and other healthcare providers, used a combination of Delphi surveys and nominal group consensus meetings to develop CTP that reflected consensus on typical treatments for patients with JDM with persistent skin rash. Consensus was reached on patient characteristics and outcome assessment. Patients should have previously received corticosteroids and methotrexate (MTX). Three consensus treatment plans were developed. Plan A added intravenous immunoglobulin (IVIG) if it was not already being used. Plan B added mycophenolate mofetil, while Plan C added cyclosporine. Continuation of previous treatments, including corticosteroids, MTX, and IVIG, was permitted in plans B and C. Three consensus CTP were developed for use in children with JDM and persistent skin rash despite complete resolution of muscle disease. These CTP reflect typical treatment approaches and are not to be considered treatment recommendations or standard of care. Using prospective data collection and statistical methods to account for nonrandom treatment assignment, it is expected that these CTP will be used to allow treatment comparisons, and ultimately determine the best treatment for these patients.

Anti-HMGCR antibodies as a biomarker for immune-mediated necrotizing myopathies: A history of statins and experience from a large international multi-center study.

In an effort to find naturally occurring substances that reduce cholesterol by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), statins were first discovered by Endo in 1972. With the widespread prescription and use of statins to decrease morbidity from myocardial infarction and stroke, it was noted that approximately 5% of all statin users experienced muscle pain and weakness during treatment. In a smaller proportion of patients, the myopathy progressed to severe morbidity marked by proximal weakness and severe muscle wasting. Remarkably, Mammen and colleagues were the first to discover that the molecular target of statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), is an autoantibody target in patients that develop an immune-mediated necrotizing myopathy (IMNM). These observations have been confirmed in a number of studies but, until today, a multi-center, international study of IMNM, related idiopathic inflammatory myopathies (IIM), other auto-inflammatory conditions and controls has not been published. Accordingly, an international, multi-center study investigated the utility of anti-HMGCR antibodies in the diagnosis of statin-associated IMNM in comparison to different forms of IIM and controls. This study included samples from patients with different forms of IIM (n=1250) and patients with other diseases (n=656) that were collected from twelve sites and tested for anti-HMGCR antibodies by ELISA. This study confirmed that anti-HMGCR autoantibodies, when found in conjunction with statin use, characterize a subset of IIM who are older and have necrosis on muscle biopsy. Taken together, the data to date indicates that testing for anti-HMGCR antibodies is important in the differential diagnosis of IIM and might be considered for future classification criteria.

Malignancy is associated with dermatomyositis but not polymyositis in Northern New England, USA.

To retrospectively evaluate the association of idiopathic inflammatory myopathy (IIM) and malignancy in patients seen at 1 academic center over a 23-year period. Patients were identified using the International Classification of Diseases, 9th edition (ICD-9) codes and diagnoses, then confirmed by chart review. Population cancer statistics obtained from the US Centers for Disease Control for Vermont and New Hampshire were used for comparison. Chart review confirmed IIM in 198 of 483 patients initially identified by ICD-9 codes. Within 5 years of diagnosis with IIM, malignancy developed in 32 patients (16.2%), 24 of whom (75%) had dermatomyositis (DM). Malignancy and DM developed within 1 year in 75%. The cancer risk associated with DM was much greater than the risk associated with other IIM. The most frequent tumor types were breast, lung, pancreas, and colon. DM patients with cancer were more frequently male and >or= 45 years of age than those without cancer. There were no cases of interstitial lung disease among patients with cancer and any form of IIM. The incidence of cancer was increased in patients with DM compared to age- and sex-matched population controls, both over a 5-year interval surrounding the diagnosis of DM and over the lifetime interval following diagnosis. The risk of cancer in IIM is concentrated among patients with DM. The association between DM and cancer was enhanced by its temporal relationship (< 1 year) in 87.5% of these cases. Patients with malignancy-associated DM were more frequently male and over age 45 and less likely to have interstitial lung disease.