Sarcoidosis and inclusion body myositis

Symptomatic myopathies in sarcoidosis: disease spectrum and myxovirus resistance protein A expression

OBJECTIVES

Symptomatic myopathy in sarcoidosis patients is not always due to sarcoid myopathy (ScM). We investigated the clinical and pathological spectrum including myxovirus resistance protein A (MxA) expression among sarcoidosis patients.

METHODS

We reviewed the Mayo Clinic database (May 1980-December 2020) to identify sarcoidosis patients with myopathic symptoms and pathological evidence of myopathy.

RESULTS

Among 5885 sarcoidosis patients, 21 had symptomatic myopathy. Eight carried a diagnosis of sarcoidosis 5.5 years (median) prior to myopathy onset. Eleven patients had ScM. The remaining had non-sarcoid myopathies (five IBM, one immune-mediated necrotizing myopathy, one non-specific myositis, two non-specific myopathy and one steroid myopathy). Estimated frequency of IBM is 85 per 100 000 sarcoidosis patients. The following features were associated with non-sarcoid myopathies (P < 0.05): (i) predominant finger flexor and quadriceps weakness, (ii) modified Rankin scale (mRS) >2 at time of diagnosis, (iii) creatine kinase >500 U/l, and (iv) absence of intramuscular granulomas. Sarcoplasmic MxA expression was observed in scattered myofibres in three patients, two of whom were tested for DM-specific autoantibodies and were negative. Immunosuppressive therapy led to improvement in mRS ≥1 in 5/10 ScM, none of the five IBM, and 3/3 remaining patients with non-sarcoid myopathies.

DISCUSSION

Symptomatic myopathy occurred in 0.36% of sarcoidosis. IBM was the second most common cause of myopathies after ScM. Frequency of IBM in sarcoidosis is higher than in the general population. Recognition of features suggestive of alternative aetiologies can guide proper treatment. Our findings of abnormal MxA expression warrant a larger study.

Granulomatous myopathy: Sarcoidosis and beyond

Non-necrotizing granulomatous inflammation is a rare but easily recognized histopathological finding in skeletal muscle biopsy. A limited number of diseases are known to be associated with non-necrotizing granulomatous myopathy. Once identified, a careful evaluation for evidence of extramuscular granulomatosis and other signs suggestive of sarcoidosis is warranted as about half of the patients have sarcoid myopathy. In addition, the presence of granulomatous myopathy should trigger a search for clinical and pathological clues of inclusion body myositis (IBM), which accounts for most of the remaining patients and can coexist with sarcoidosis. Recognizing the features of IBM in patients with granulomatous myopathy can potentially spare the patients from unnecessary exposure to immunosuppressive therapies. In patients whose granulomatous myopathy remain unexplained, further investigations should aim at identifying myasthenia gravis and other autoimmune disorders, especially those known to cause granulomatous inflammation in other organs. Laboratory investigations should include acetylcholine receptor, antimitochondrial, antineutrophil cytoplasmic, thyroglobulin, and thyroid peroxidase autoantibodies. In the appropriate clinical context, exposure to immune checkpoint inhibitors and chronic graft-vs-host disease can be causes of granulomatous myopathy. In cases of unexplained granulomatous myopathy, natural killer/T-cell lymphoma should be considered and careful histopathological examination for atypical cells and appropriate immunostaining is crucial. Identifying the etiology of granulomatous myopathy in each patient can guide appropriate treatment.

Inclusion body myositis and associated diseases: an argument for shared immune pathologies

Inclusion body myositis (IBM) is the most prevalent idiopathic inflammatory myopathy (IIM) affecting older adults. The pathogenic hallmark of IBM is chronic inflammation of skeletal muscle. At present, we do not classify IBM into different sub-entities, with the exception perhaps being the presence or absence of the anti-cN-1A-antibody. In contrast to other IIM, IBM is characterized by a chronic and progressive disease course. Here, we discuss the pathophysiological framework of IBM and highlight the seemingly prototypical situations where IBM occurs in the context of other diseases. In this context, understanding common immune pathways might provide insight into the pathogenesis of IBM. Indeed, IBM is associated with a distinct set of conditions, such as human immunodeficiency virus (HIV) or hepatitis C-two conditions associated with premature immune cell exhaustion. Further, the pathomorphology of IBM is reminiscent of other muscle diseases, notably HIV-associated myositis or granulomatous myositis. Distinct immune pathways are likely to drive these commonalities and senescence of the CD8+ T cell compartment is discussed as a possible mechanism of pathogenesis. Future effort directed at understanding the co-occurrence of IBM and associated diseases could prove valuable to better understand the enigmatic IBM pathophysiology.

Clinical characteristics and outcome in muscular sarcoidosis: a retrospective cohort study and literature review

We evaluated the clinical features and treatment response of patients with muscular sarcoidosis. A retrospective cohort of 12 patients showed muscle weakness in 11 and myalgia in seven. One had focal myositis. Four had a negative medical history for sarcoidosis. Muscle imaging showed muscle edema in all and replacement of muscle tissue by fat in half of patients. Muscle biopsy showed non-caseating granulomas in six of nine patients and inflammation without granulomas in three. None of the muscle biopsies showed features of inclusion body myositis. Imaging in three patients without muscle biopsy showed focal intramuscular masses or a 'tiger man' appearance typical for muscular sarcoidosis. Treatment consisted of glucocorticoids in 11, additional methotrexate or azathioprine in seven and infliximab in two patients. Half of the patients had symptoms leading to substantial disability (modified Rankin scale score >1) at last follow-up. A literature review of articles describing more than one muscular sarcoidosis patient published in the last 25 years identified 153 additional patients. We found muscular sarcoidosis to be a rare and often disabling disease which may be recognized by typical muscle imaging characteristics and add focal myositis to the muscular phenotypes of sarcoidosis.

Association Between Treatment-Resistant Sarcoid Myopathy and Inclusion Body Myositis

The association between sarcoid myopathy and inclusion body myositis is a rare phenomenon that is not well understood. In this case, we present a 46-year-old female with a five-year history of sarcoidosis who became refractory to treatment, experiencing progressive deterioration and muscle wasting. The patient’s distribution of muscle weakness did not follow characteristic patterns of inclusion body myositis. Yet, a subsequent deltoid biopsy revealed diagnostic findings typical of inclusion body myositis. This case report reveals an association between treatment-resistant sarcoid myopathy and the evolution of inclusion body myositis in the absence of characteristic clinical findings.

Myopathies featuring non-caseating granulomas: Sarcoidosis, inclusion body myositis and an unfolding overlap

Granulomatous myopathies are etiologically heterogeneous myopathies, pathologically characterized by the presence of intramuscular granulomas. Treatment outcomes are variable. We aimed to identify prognostic factors of treatment outcomes in myopathies featuring non-caseating granulomas. Sixteen patients were identified (9 sarcoid myopathy, 6 inclusion body myositis, and 1 granulomatous myopathy of indeterminate cause) over a 21-year period. The median age at diagnosis was 67 years in sarcoid myopathy group, and 64 years in inclusion body myositis group. Three inclusion body myositis patients were initially diagnosed with sarcoid myopathy based on the presence of systemic features of sarcoidosis and findings on muscle biopsies, but subsequent biopsies performed because of treatment refractoriness, showed all canonical pathologic features of inclusion body myositis. We identified sarcoplasmic congophilic inclusions in 6 sarcoid myopathy patients without associated rimmed vacuoles or typical weakness pattern of inclusion body myositis. Four inclusion body myositis and 4 of 5 sarcoid myopathy patients with congophilic inclusions were refractory to immunotherapy. Our study portrays the overlapping clinical and pathological features of sarcoid myopathy and inclusion body myositis. The presence of sarcoplasmic congophilic inclusions in sarcoid myopathy may predict an unfavorable outcome of immunosuppressive therapy, but a larger prospective study is required to further validate this observation.

Clinical, Histological, and Immunohistochemical Findings in Inclusion Body Myositis

Sporadic inclusion body myositis (sIBM) is considered the most common acquired myopathy aged over 50 years. The disease is characterized by a particular process of muscle degeneration characterized by abnormal deposit of protein aggregates in association with inflammation. The aim of this study was to present clinical and muscle histopathological findings, including immunostaining for LC3B, p62, α-synuclein, and TDP-43, in 18 patients with sIBM. The disease predominated in males (61%) and European descendants, with onset of clinical manifestations around 59 years old. The most common symptoms were muscle weakness, falls, dysphagia, and weight loss. Hypertension was the main comorbidity. Most of the cases presented with paresis predominantly proximal in lower limbs and distal in upper limbs. Immunosuppressive treatment showed to be not effective. Muscle histological findings included dystrophic changes, endomysial inflammation, increased lysosomal activity, and presence of rimmed vacuoles and of beta-amyloid accumulation, in addition to high frequency of mitochondrial changes. There was increased expression of LC3B, p62, α-synuclein, and TDP-43 in muscle biopsies. The sIBM has characteristic clinical and histological findings, and the use of degeneration and autophagic markers can be useful for the diagnosis.

Sarcoidosis: Is It a Possible Trigger of Inclusion Body Myositis?

Sarcoidosis is a multisystem disorder of unknown etiology, characterized pathologically by the presence of nonnecrotizing granulomatous inflammation in affected organs. Although skeletal muscle is involved in 50–80 percent of individuals with sarcoidosis, symptomatic myopathy has been shown to be a rare manifestation of the disease. Inclusion body myositis (IBM) is a rare acquired idiopathic inflammatory myopathy with the insidious onset of asymmetric and distal muscle weakness that characteristically involves the quadriceps, tibialis anterior, and forearm flexors. Moreover, dysphagia can be the presenting complaint in one-third of patients. Herein, we are presenting a case of 67-year-old African American female who presented with one-month history of new onset progressive dyspnea on exertion. She was diagnosed with stage IV sarcoidosis based on chest CT scan findings and transbronchial lung biopsy revealing nonnecrotizing granulomatous inflammation. Over the next three months after her diagnosis, she presented to the hospital with progressive dysphagia associated with asymmetrical distal muscle weakness. A quadriceps muscle biopsy revealed features consistent with inclusion body myositis. We are reporting this case as it may support the hypothesis of sarcoidosis being a trigger that possibly promotes the development of inclusion body myositis, leading to a very poor prognosis.

Sarcoidosis: a rheumatologist's perspective

Sarcoidosis is a systemic disorder of unknown etiology, which may involve various tissues and organs and is characterized by a noncaseating granuloma reaction. While pathogenesis is not yet clear, cellular immune system activation and nonspecific inflammatory response occur secondarily to several genetic and environmental factors. T helper 1-cells and macrophage-derived pro-inflammatory cytokines stimulate the inflammatory cascade and formation of granuloma occurs as a result of tissue permeability, cell influx, and local cell proliferation. The different prevalence, clinical results, and disease course observed in different races and ethnic groups, is an indicator of the heterogeneous nature of the disease. Sarcoidosis may mimic and/or may occur concomitantly with numerous primary rheumatic diseases. This disease most commonly presents with bilateral hilar lymphadenopathy, pulmonary infiltrations, and skin and eye lesions. Locomotor system involvement is observed at a range of 15% and 25%. Two major joint involvements have been described: acute and chronic form. The most common form, the acute form, may be the first sign of sarcoidosis and present with arthralgia, arthritis, or periarthritis. Chronic sarcoid arthritis is usually associated with pulmonary parenchymal disease or other organ involvement and occurs rarely. While asymptomatic muscular involvement is reported between 25% and 75%, symptomatic muscular involvement is very rare. Symptomatic myopathy may present as three different types: chronic myopathy, palpable nodular myositis, or acute myositis. Even if rare, 2-5% of cases may exhibit osseous involvement and it is frequently associated with lupus pernio, chronic uveitis, and multisystemic disease. Sarcoidosis was reported together with different rheumatologic diseases. There are studies showing that sarcoidosis may mimic the clinical and laboratory findings of these disorders. Nonsteroidal anti-inflammatory drugs and corticosteroids are used for treating the symptoms of rheumatologic findings. In patients who are unresponsive to corticosteroids, immunosuppressive and anti-tumor necrosis factor alpha drugs may be used. In this review, the incidence of rheumatologic symptoms, the clinical findings, and the treatment of rheumatologic manifestations of sarcoidosis are discussed.

Inclusion body myositis and sarcoid myopathy: coincidental occurrence or associated diseases

Inclusion body myositis (IBM) is a slowly progressive inflammatory myopathy characterized by selective weakness of finger flexors and quadriceps muscles commonly refractory to treatment. Another chronic inflammatory disorder, sarcoidosis, commonly involves muscle. The comorbidity of inclusion body myositis and sarcoid myopathy is rare. We describe clinical and muscle biopsy findings of a patient with sarcoidosis and inclusion body myositis. A 66-year-old man presented with a 6-year history of progressive, asymmetrical and selective weakness of the quadriceps, biceps and finger flexor muscles; he had a remote history of pulmonary sarcoidosis. A quadriceps muscle biopsy revealed a chronic inflammatory myopathy with ubiquitinated inclusion bodies, rimmed vacuoles, expression of major histocompatibility complex class I, numerous COX-negative fibers and TDP-43 cytoplasmic aggregates (features of IBM) and multiple non-necrotizing granulomata (feature of sarcoidosis). Clinical and histopathologic features of the current illness suggested the patient had sarcoidosis with inclusion body myositis overlap. This patient may represent the coincidental occurrence of both idiopathic inflammatory disorders. Alternatively, sarcoidoisis may promote the development of inclusion body myositis by a similar immune-mediated pathophysiologic process.

Neurosarcoidosis: Clinical manifestations, diagnosis and treatment

Sarcoidosis is an idiopathic granulomatous disease affecting multiple organs. Neurosarcoidosis, involving the central and/or peripheral nervous systems, is a relatively rare form of sarcoidosis. Its clinical manifestations include cranial neuropathies, meningitis, neuroendocrinological dysfunction, hydrocephalus, seizures, neuropsychiatric symptoms, myelopathy and neuropathies. The diagnosis is problematic, especially when occurring as an isolated form without other organ involvement. Distinguishing neurosarcoidosis from other granulomatous diseases and multiple sclerosis is especially important. Although biopsy of neural tissue is the gold standard for the diagnosis of neurosarcoidosis, this is often not practical and the diagnosis must be inferred though other tests, often coupled with biopsy of extraneural organs. Corticosteroids and other immuno-suppressants are frequently used for the treatment of neurosarcoidosis. This article reviews the epidemiology, pathogenesis, pathology, clinical features, diagnosis, diagnostic tests, diagnostic criteria, and therapy of neurosarcoidosis.

Rheumatologic manifestations of sarcoidosis

Sarcoidosis is a systemic, clinically heterogeneous disease characterized by the development of granulomas. Any organ system can be involved, and patients may present with any number of rheumatologic symptoms. There are no U.S. Food and Drug Administration-approved therapies for the treatment of sarcoidosis. Diagnosing sarcoidosis becomes challenging, particularly when its complications cause patients' symptoms to mimic other conditions, including polymyositis, Sjögren syndrome, or vasculitis. This review presents an overview of the etiology of and biomarkers associated with sarcoidosis. We then provide a detailed description of the rheumatologic manifestations of sarcoidosis and present a treatment algorithm based on current clinical evidence for patients with sarcoid arthritis. The discussion will focus on characteristic findings in patients with sarcoid arthritis, osseous involvement in sarcoidosis, and sarcoid myopathy. Arthritic conditions that sometimes coexist with sarcoidosis are described as well. We present two cases of sarcoidosis with rheumatologic manifestations. Our intent is to encourage a multidisciplinary, translational approach to meet the challenges and difficulties in understanding and treating sarcoidosis.