Extranodal NK/T-cell Lymphoma Mimicking Granulomatous Myositis: A Case Report

Norihiko Kawaguchi; Rumiko Izumi; Masahiro Kobayashi; Maki Tateyama; Naoki Suzuki; Fumiyoshi Fujishima; Juichi Fujimori; Masashi Aoki; Ichiro Nakashima

doi:10.2169/internalmedicine.0859-18

This article has now been updated. Please use the final version.

Extranodal NK/T-cell Lymphoma Mimicking Granulomatous Myositis: A Case Report

Norihiko Kawaguchi, Rumiko Izumi, Masahiro Kobayashi, Maki Tateyama, Naoki Suzuki, Fumiyoshi Fujishima, Juichi Fujimori, Masashi Aoki, Ichiro Nakashima

Author information

Norihiko Kawaguchi
Department of Neurology, Tohoku Medical and Pharmaceutical University, Japan
Rumiko Izumi
Department of Neurology, Tohoku University School of Medicine, Japan
Masahiro Kobayashi
Department of Hematology and Rheumatology, Tohoku University Graduate School of Medicine, Japan
Maki Tateyama
Department of Neurology, Tohoku University School of Medicine, Japan
Department of Neurology, Iwate National Hospital, Japan
Naoki Suzuki
Department of Neurology, Tohoku University School of Medicine, Japan
Fumiyoshi Fujishima
Department of Pathology, Tohoku University Hospital, Japan
Juichi Fujimori
Department of Neurology, Tohoku Medical and Pharmaceutical University, Japan
Masashi Aoki
Department of Neurology, Tohoku University School of Medicine, Japan
Ichiro Nakashima
Department of Neurology, Tohoku Medical and Pharmaceutical University, Japan

Keywords: Extranodal NK/T-cell lymphoma (ENKTL), granulomatous myositis, eyelid swelling, muscle biopsy, immunohistochemistry

JOURNAL OPEN ACCESS Advance online publication

Article ID: 0859-18

DOI https://doi.org/10.2169/internalmedicine.0859-18

The final version of this article is now available: Vol. 58 (2019), No. 2 pp. 277-282

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Abstract

Extranodal NK/T-cell lymphoma (ENKTL) is an aggressive non-Hodgkin lymphoma that typically develops in the upper aerodigestive tract. We encountered an ENKTL patient who presented with generalized muscle weakness with eyelid swelling, diplopia, and facial edema. A muscle biopsy revealed lymphocytic infiltration without significant atypia; some lymphocytes formed granuloma-like structures. Although the initial response to steroids was encouraging, an ulcerative eruption appeared in the thigh, and a skin biopsy revealed lymphocytes with atypia. A re-analysis of the muscle biopsy with additional immunohistochemistry revealed neoplastic NK/T lymphocytes in the granulomatous structures. Our case highlights the significance of re-evaluating muscle biopsy specimens in cases of atypical myositis.

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