Seronegative dermatomyositis presenting with features of anti‐MDA5 subtype

Abstract

Dermatomyositis is a chronic inflammatory disorder of muscles and skin, presenting with muscle weakness, characteristic rash, and classic serology findings. Histologically, cutaneous lesions show interface dermatitis with mild perivascular lymphocytic infiltrate and increased intradermal mucin. These findings are non-specific, and the diagnosis is based on clinicopathologic correlation and serology results. However, variation in clinical presentation, serology, and histology can make the diagnosis difficult and requires cognizance of uncommon findings that may serve as a clue to the diagnosis. Herein, we report such a case with unusual histologic features of vascular damage and deep dermal necrosis in a seronegative patient who presented with clinical features of anti-MDA5 variant of dermatomyositis.

Clinical and histopathological features of adult patients with dermatomyositis and melanoma differentiation associated‐5 autoantibody seropositivity status, as determined by commercially available testing: a retrospective, single‐institution comparative cohort study

“…Vascular damage along with deep dermal necrosis has also been reported in association with MDA-5-positive DM. 17 Of note, the presence of spongiosis cannot exclude the diagnosis of DM, as we observed it in nine biopsies; however, its relevance with regard to MDA status requires further study.…”

Cricopharyngeal bar and dermatomyositis: A cause of rapidly progressive dysphagia

“…[21][22][23]26 However, there have been several reports of an association between cricopharyngeal bars and IIM. 1,3,[8][9][10][11][12][13][14][15][16][17][18][19][20] They have been found at increased rates in patients with an IIM compared to patients with a neurogenic cause of dysphagia as well as aged controls, 3 but similar to the general population, tend to occur in an older subset of patients. 3,20,26 When CPBs are identified in IIM patients, manometry typically…”

“…A CPB is a radiological description of the prominence of the cricopharyngeus and can be found incidentally in the general population and has also been described in the presence of IIM with suggested increased incidence in this population. 1,3,[8][9][10][11][12][13][14][15][16][17][18][19][20] In this case report we present a patient with dermatomyositis who presented with dysphagia and a CPB and discuss the significance of these findings.…”

Polymyositis Presenting With Nontraumatic Rhabdomyolysis and Dysphagia: A Case Report

“…The diagnosis and classification of PM and other IIMs have been a source of discussion for the past several decades, with multiple proposed classification criteria. 4 , 7 - 10 Polymyositis can be a complex and difficult diagnosis due to its overlapping features with other IIMs and autoimmune diseases. Most classification criteria emphasize the following: (1) muscle weakness, (2) muscle biopsy, (3) EMG findings suggestive of myositis, and (4) elevation of CK and other muscle enzymes.…”

“…Antibody detection in inflammatory myopathies varies, with any known autoantibody present in 60% to 80% of cases and a MSA present in 40% to 50% of cases. [5][6][7][8] The sensitivities of muscle biopsies, considered the gold standard, have been reported to be anywhere from 45% to 85%.…”