Published online Mar 6, 2020. doi: 10.12998/wjcc.v8.i5.963
Peer-review started: September 26, 2019
First decision: November 21, 2019
Revised: November 23, 2019
Accepted: December 13, 2019
Article in press: December 13, 2019
Published online: March 6, 2020
Processing time: 161 Days and 18.8 Hours
Natural killer (NK)/T cell lymphoma is a rare and highly aggressive malignant tumor, and is a special form of non-Hodgkin's lymphoma. Although extranodal involvement is frequently found in tissues such as the skin, testicular and gastrointestinal tract etc, its presence in skeletal muscle has scarcely been reported in the literature.
We report a case of extranodal NK/T cell lymphoma with muscle swelling as the first clinical manifestation. A 42-year-old man, who initially presented with localized swelling in the double lower extremities, demonstrated gradual facial and eyelid swelling, and his imaging results showed multiple sites of muscle damage throughout the body. The final pathological results suggested NK/T cell lymphoma, and immunohistochemistry showed CD20 (-), CD3Ɛ (+), CD30 (+), CD56 (-), EBER (+), Ki67 (60%), TIA-1 (+) and CD68 (±) staining. The muscle swelling significantly improved after treatment with chemotherapy regimens.
This disease is difficult to diagnose and highly invasive, and should be included in the differential diagnosis of unexplained muscle swelling.
Core tip: Extranodal natural killer/T cell lymphoma (NK/T cell lymphoma) is a distinct clinicopathologic entity in non-Hodgkin's lymphoma, having various extranodal manifestations, and a high incidence in Asian and South American populations. In this article, we describe a 42-year-old Asian man who presented with muscle swelling as the first clinical manifestation, and was initially diagnosed with polymyositis. Upon further examination, he was definitively diagnosed with extranodal NK/T cell lymphoma. Therefore, we provide a review of the literature to further understand extranodal NK/T cell lymphoma in muscles.