Downloaded from http://journals.lww.com/amjdermatopathology by BhDMf5ePHKbH4TTImqenVIF9RwgEptflZfms2UY9VcCTC1OzzMV2kC9IMtbgkEPU on 08/23/2020 CLINICAL PATHOLOGIC CHALLENGE ANSWER Rash Associated With Arthritis and Pleuritic Chest Pain: Answer Qiong Wu, MD,* Daniel R. Mazori, MD,† Robin Burger, MD,†‡ Edward Heilman, MD,† and Viktoryia Kazlouskaya, MD, PhD† (Am J Dermatopathol 2020;42:710–711) (Continued from page e124) ANSWER Adult-onset Still’s disease with a dermatomyositis-like eruption. Adult-onset Still’s disease (AOSD) is a systemic inflam- matory disorder of unknown etiology affecting young adults. The diagnosis of AOSD is one of exclusion and based on clinical manifestations (spiking fever, polyarthralgia/arthritis, transient evanescent rash, pharyngitis, lymphadenopathy, hepa- tomegaly, and splenomegaly) and laboratory findings (leuko- cytosis with more than 80% neutrophils, abnormal liver function tests, elevated ferritin with low glycosylated ferritin, and negative antinuclear antibody and rheumatoid factor). 1,2 The typical AOSD rash is an evanescent, salmon-pink, maculopapular eruption and is one of the most known features of AOSD. It appears with fever spikes and is accepted as a major criterion of diagnosis. 3,4 Nonclassic per- sistent skin lesions of AOSD have also been reported, includ- ing persistent plaques and linear pigmentation, eczematous lesions, urticaria and angioedema, vesiculo-pustules on the hands and feet, persistent generalized erythema, facial edema, and a prurigo pigmentosa-like eruption. 5 In addition, a dermatomyositis-like rash has been described in a few case reports in association with interstitial lung disease and a grave prognosis. 4,6 The histopathology of the typical AOSD rash reveals a mixed perivascular inflammatory infiltrate without epidermal changes. On the other hand, the histopathology of the persistent skin lesions of AOSD includes 2 different impor- tant findings: a pattern of dyskeratosis in the superficial epidermis without basilar dyskeratosis, and a sparse superficial dermal infiltrate often containing neutrophils without vasculitis. 3 Our case demonstrated a dermatomyositis-like eruption in AOSD with skin lesions mimicking Gottron’s papules (papules on the knuckles), Gottron’s sign (papules on the knees), V-neck sign and shawl sign (photodistributed rash on the upper chest and upper back), and holster sign (rash on the lateral thighs). However, there were no nailfold capil- lary changes, no heliotrope sign (periocular edematous ery- thema), and no abnormality in creatine kinase. Moreover, the anti-Jo-1 antibody was negative, and the histopathology lacked features of dermatomyositis (vacuolar interface derma- titis and dermal mucin). As a result, our case demonstrates that the persistent rash in AOSD may clinically mimic der- matomyositis and emphasizes the role of clinicopathologic correlation in establishing the correct diagnosis of AOSD. Although rare, myositis has also been described in AOSD, which may make the distinction between AOSD and dermatomyositis even more challenging. 7,8 In our opinion, the proximal nailfolds should always be examined, as the absence of nailfold capillary changes may help point to a diagnosis of AOSD. Furthermore, the combination of multi- ple individual necrotic keratinocytes in the upper epidermis and a dermal infiltrate of neutrophils is characteristic and helps to further establish the diagnosis of AOSD. 9 Complica- tions of dermatomyositis-like AOSD may include interstitial lung disease and hemophagocytic syndrome, and thus pa- tients should be monitored appropriately. 5 Our patient received dexamethasone 10 mg daily with resolution of his skin lesions, as well as reduction in erythrocyte sedimentation rate and C-reactive protein. Methotrexate 12.5 mg weekly was then added to address the arthropathy, which led to sig- nificant improvement. REFERENCES 1. Yamaguchi M, Ohta A, Tsunematsu T, et al. Preliminary criteria for classification of adult Still’s disease. J Rheumatol. 1992;19:424–430. 2. Fautrel B, Zing E, Golmard JL, et al. Proposal for a new set of classifi- cation criteria for adult-onset still disease. Medicine. 2002;81:194–200. 3. Giacomelli R, Ruscitti P, Shoenfeld Y. A comprehensive review on adult onset Still’s disease. J Autoimmun. 2018;93:24–36. 4. Martin-Nares E, Lopez-Iniguez A, Castro-Gallegos PE, et al. Adult-onset still disease presenting with interstitial lung disease and dermatomyositis- like atypical persistent eruption successfully treated with mycophenolate mofetil. J Clin Rheumatol. 2018. 5. Narvaez Garcia FJ, Pascual M, Lopez de Recalde M, et al. Adult-onset Still’s disease with atypical cutaneous manifestations. Medicine (Balti- more). 2017;96:e6318. From the *Department of Dermatology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; †Department of Derma- tology, SUNY Downstate Medical Center, Brooklyn, NY; and ‡Ackerman Academy of Dermatopathology, NY. The authors declare no conflicts of interest. Correspondence: Viktoryia Kazlouskaya, MD, PhD, Department of Derma- tology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203 (e-mail: viktoriakozlovskaya@yahoo.com). Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. 710 | www.amjdermatopathology.com Am J Dermatopathol  Volume 42, Number 9, September 2020 Copyright © 2020 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.