Necrosis of muscle with carcinoma: myositis or myopathy?

Cancer and immune-mediated necrotizing myopathy: a longitudinal referral case-controlled outcomes evaluation

OBJECTIVES

To investigate immune-mediated necrotizing myopathy (IMNM) association with cancer and its clinical implications.

METHODS

IMNM cases were identified 1 January 2000 to 31 December 2020 matching sex and age controls (4:1).

RESULTS

A total of 152 patients with IMNM were identified and among serologically tested, 60% (83/140) were HMGCR-IgG+, 14% (20/140) were SRP-IgG+ and 26% (37/140) were seronegative. Cancer rates were not significantly different between serological subgroups; 18.1% (15/83) HMGCR-IgG+, 25% (5/20) SRP-IgG+ and 30% (11/37) seronegative (P = 0.34). Cancer screening was performed within 12 months from IMNM diagnosis in 88% (134/152) (whole-body CT plus FDG-PET CT in 53, CT alone in 72 and FDG-PET alone in 9). FDG-PET/CT was positive in 73% (25/34) of cancers. Increasing age was the only risk associated with cancer (P = 0.02). The odds of developing cancer at ±3 or ±5 years from IMNM diagnosis was not higher than controls (OR = 0.49; CI: 0.325-0.76). Lifetime IMNM diagnosis of cancer was less compared with controls (OR = 0.5 CI: 0.33-0.78, P = 0.002). Most patients responded to treatment (137/147, P < 0.001). Death and treatment response did not significantly differ between cancer [23% (8/34); 88% (29/33)] and non-cancer patients [19% (23/118); 92% (108/118)]. In total, 13% (20/152) of patients died during follow-up compared with 14% (41/290) of medicine and 16% (46/290) of neurology controls (P = 0.8). Seropositives had greater life expectancy than seronegatives (P = 0.01).

CONCLUSIONS

Greater cancer risk is not observed in IMNM vs controls. Cancer screening in IMNM should be individualized based on age-personal and family history, including consideration of FDG-PET/CT. Immune-treatment response did not differ with cancer.

Immune-mediated necrotizing myopathy: clinical features and pathogenesis

Immune-mediated necrotizing myopathy (IMNM) is a group of inflammatory myopathies that was distinguished from polymyositis in 2004. Most IMNMs are associated with anti-signal recognition particle (anti-SRP) or anti-3-hydroxy-3-methylglutaryl-coA reductase (anti-HMGCR) myositis-specific autoantibodies, although ~20% of patients with IMNM remain seronegative. These associations have led to three subclasses of IMNM: anti-SRP-positive IMNM, anti-HMGCR-positive IMNM and seronegative IMNM. IMNMs are frequently rapidly progressive and severe, displaying high serum creatine kinase levels, and failure to treat IMNMs effectively may lead to severe muscle impairment. In patients with seronegative IMNM, disease can be concomitant with cancer. Research into IMNM pathogenesis has shown that anti-SRP and anti-HMGCR autoantibodies cause weakness and myofibre necrosis in mice, suggesting that, as well as being diagnostic biomarkers of IMNM, they may play a key role in disease pathogenesis. Therapeutically, treatments such as rituximab or intravenous immunoglobulins can now be discussed for IMNM, and targeted therapies, such as anticomplement therapeutics, may be a future option for patients with refractory disease.

Paraneoplastic Necrotizing Myopathy with a Mild Inflammatory Component: A Case Report and Review of the Literature

Inflammatory myopathies such as dermatomyositis and polymyositis are well-recognized paraneoplastic syndromes. Little is known, however, about necrotizing myopathies in association with cancer. We here describe a case of paraneoplastic necrotizing myopathy with a mild inflammatory infiltrate in a patient with adenocarcinoma. After the rapid development of a severe, disabling muscle weakness, the patient experienced near complete recovery within 4 months under oral prednisone treatment. In the context of the presented case, we will review current knowledge about paraneoplastic necrotizing myopathies.

Fatal myocarditis with acute polymyositis in a young adult

A 21 year old woman presented with acute polymyositis associated with fatal myocarditis. The significance of cardiac involvement in polymyositis is discussed in relation to this unusually fulminant case.

Paraneoplastic syndromes. How to recognize the remote neurologic effects of cancer

Neurologic paraneoplastic syndromes occur in patients with all forms of malignancy. Their effects on the central and peripheral nervous systems are devastating. A neurologic abnormality may be the first manifestation of malignancy or can occur late in the course of the disease. Early recognition can lead to effective treatment of a paraneoplastic syndrome and a potential cure of the underlying cancer.

Dermatomyositis

Dermatomyositis and polymyositis are related disorders of unknown cause in which immunologic changes may be important. They sometimes overlap with other collagen vascular diseases, and not infrequently are associated with malignancy. The clinical features of the adult and juvenile forms of the disorder and the visceral manifestations of DM-PM are outlined, along with enzymatic, electromyographic, and histologic aids to diagnosis. While the cutaneous lesions often are resistant to treatment, systemic involvement may respond to corticosteroids or to immunosuppressive drugs. Treatment definitely alters the prognosis in cases not associated with malignancy.

Classification of myositis. Correlations between morphological and clinical classifications of inflammatory muscle disease

Insufficient clinical data given to pathologists often hamper the differentiation of inflammatory muscle diseases. Thus we proved the value of a classification based only upon morphological criteria. Among 160 biopsies with myositic pattern (4.9% of a series of 3264 muscle biopsies) we could distinguish the following groups: Interstitial inflammation with only few fibre necroses (17.6%), predominance of fibre necroses with few inflammatory infiltrates (38.1%), small vessel vasculitis (20.0%), arteritis (13.1%), granulomatous myositis (8.8%) and polymorphonuclear leukocytic infiltrates (2.6%). This classification is compared with the used clinical diagnoses. Some special morphological aspects (histometric and immunocytologic examinations, tissue calcification, inclusion bodies, neurogenic atrophies) are analysed and so are some clinical peculiarities (e.g. malignoma-association, differentiation of mixed connective tissue syndrome, drug-induced reactions). The diagnostic value of purely morphologic criteria is restricted. For better diagnostic work a great number of clinical informations is required. Nevertheless, certain morphological patterns give important directions, e.g. to occult malignoma.

The inflammatory myopathies

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Teaching monograph: pathology of skeletal muscle diseases

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Muscle biopsy in polymyositis and dermatomyositis: a clinicopathological study

The initial muscle biopsies of 30 patients with active polymyositis or dermatomyositis have been assessed histologically and morphometrically. Only 1 patient (3.3%) had a normal biopsy, while 3 had a normal electromyograph and 8 had a normal serum CPK level. No significant morphological differences were found between the various diagnostic subgroups. Sequential biopsies of 11 of these patients treated either with corticosteroids only or with intensive immunosuppression were studied. With response to treatment atrophy factors, variability coefficients, internal nuclei count, and the various histological changes improved in the whole group of patients. However, there was no consistent correlation between any of the morphological features or between these and clinical parameters in individual patients. The percentage of fibres with internal nuclei in the initial biopsy was lower (P < 0.001) in patients responding to up to 60 mg prednisolone per day than in those who eventually required cytotoxic drugs in addition.

Quantitative analysis of voluntary muscles from routine autopsy material with special reference to the problem of remote carcinomatous changes ("neuromyopathy")

Specimens from the deltoid muscle of 210 randomly selected autopsy cases without previous clinical evidence of primary neuromuscular impairment were examined with regard to the influence of extramuscular diseases on voluntary muscle. Differences between malignant tumours and other disorders were of special interest with respect to the question of the possible existence of a remote effect of cancer on skeletal muscle. The number of central nuclei within muscle fibre cross sections was considered as the most simple parameter for myopathic reaction. Atrophic fibre changes were examined quantitatively by measurement of the orthogonal fibre diameters and calculating the variation of fibre size. In addition, a semi-quantitative histological evaluation of the muscles was performed. While tumor cases did not show a significant difference from the remainder with respect to myopathic changes, they did display a significant difference with regard to scattered and small-group fibre atrophy. The reasons for the muscular changes are discussed. From the present investigation the changes seem to be due chiefly to metabolic impairment and wasting. No signs for a specific carcinotoxic effect on skeletal muscles could be demonstrated.

Dermatomyositis: observations on the use of immunosuppressive therapy and review of literature. Cairo--Glasgow study group

Seven young adults, six of whom were male, all suffering from dermatomyositis unassociated with malignancy are described. These patients were not adequately controlled with high doses of corticosteroids but all responded when immunosuppressive therapy was also given.

Subclinical myopathic findings in patients affected by malignant tumours. An autopsy study

Histoenzymologic studies on representative muscles and the peripheral microcirculation from selected autopsies of non cachectic patients dying of neoplasms, without signs of neuromuscular involvement, demonstrate a high incidence of neuromuscular and microcirculatory changes. A correlation between neuromuscular changes and the peripheral microcirculation particularly evident in myopathic cases is discussed.

Acute dermatomyositis-polymyositis and malignancy

A partial review of selected published case reports of AD-P associated with malignancy has been enhanced by the presentation of pertinent data on 15 unreported examples of the association. It is noteworthy that the first case in current literature of AD-P associated with a malignancy was described in 1916. The brief clinical report of a patient with proximal muscle weakness and skin lesions, with the obvious association with a malignancy (adenocarcinoma of the stomach), describes an example that has been repeated many times with different types of tumors but with essentially no variations in the clinical findings. In 1959 Williams identified 590 cases of AD with an overall tumor rate of 15%, and recently Barnes identified 258 cases of AD associated with a malignancy. The original designation, dermatomyositis or AD, has now been expanded to include proximal muscle polymyositis with systemic involvement, which syndrome at the current state of the art is indistinguishable clinically and pathologically from AD except for the lack of skin lesions. It may be that at some future time one or more immunologic features may differnetiate the clinical entity polymyositis from AD and further subdivide each of these entitites from similar clinical syndromes associated with a malignancy. However, the problem in management in either AD or polymyositis is similar. A number of patients with a malignancy and muscle weakness or neuropathy have been reported. These associations have been mentioned briefly, but insufficient data are available to determine whether these should be considered as a variant of AD-P or only casually related conditions with certain clinical features in common. Most of the patients described in the literature of AD-P with an associated malignancy have had skin lesions; a minority only have lacked this feature. However, unless a patient is followed carefully, it is possible for a transient or evanescent erythema or insignificant skin lesions to be present and not recorded in the case record.

Prognosis in adult polymyositis

The effects of long-term corticosteroid treatment have been assessed in 20 patients with polymyositis. Cases were only accepted if a muscle biopsy showed the characteristic features of inflammation and muscle fibre degeneration. If the muscle disorder was only a minor feature of generalised collagen disease or there was evidence of coexisting neuropathy, the patients were excluded. Over a mean follow-up period of 5 years, 8 patients died and only 4 improved. These results have been compared with those in other series. An attempt has been made to correlate muscle biopsy findings with prognosis, and the reasons for the poor outcome are discussed.

Degeneration of muscle in association with carcinoma of the bronchus

The clinical features and necropsy findings are described in three cases in which severe and rapidly progressive muscle weakness developed in association with carcinoma of the bronchus. In all three cases, muscular weakness was directly responsible for death. Histological and ultramicroscopical examination in all cases showed an unusual type of degeneration of muscle fibres accompanied by degeneration of intramuscular nerve fibres, but without involvement of the central nervous system, or of the peripheral nerve trunks. The findings are compared with those of previously reported cases, and possible mechanisms for the muscle degeneration are discussed.