Shibata Chikako, Kato Jun, Toda Nobuo, Imai Makoto, Fukumura Yukiyo, Arai Junya, Kurokawa Ken, Kondo Mayuko, Takagi Kaoru, Kojima Kentaro, Ohki Takamasa, Seki Michiharu, Yoshida Masanobu, Suzuki Akitake, Tagawa Kazumi
Department of Gastroenterology, Mitsui Memorial Hospital, 1 Kandaizumicho Chiyoda-ku, Tokyo, 101-8643, Japan.
Department of Rheumatology, Mitsui Memorial Hospital, 1 Kandaizumi cho Chiyoda-ku, Tokyo, 101-8643, Japan.
J Med Case Rep. 2019 Jun 2;13(1):168. doi: 10.1186/s13256-019-2105-9.
While dermatomyositis is often associated with malignancy, several autoimmune diseases like myositis can be caused by immune checkpoint inhibitors. Differentially diagnosing malignancy-associated dermatomyositis or myositis caused by immune checkpoint inhibitors is sometimes difficult, particularly when a patient with malignancy shows the symptoms of myositis after checkpoint inhibitor administration. We experienced such a case in which we had difficulties in diagnosing paraneoplastic dermatomyositis or drug-associated myositis. In this case, all of our team initially assumed that the diagnosis was myositis caused by immune checkpoint inhibitors. However, it turned out finally that the diagnosis was paraneoplastic dermatomyositis. Because the diagnosis was unexpected, we report here.
We report the case of a 71-year-old Japanese man who developed clinical symptoms of myositis, such as muscle aches and weakness, after initiation of nivolumab therapy for his gastric cancer. He was initially diagnosed with nivolumab-induced myositis, because the myositis symptoms appeared after nivolumab administration, and nivolumab is known to trigger various drug-associated autoimmune diseases. However, according to his characteristic skin lesions, the type of muscle weakness, his serum marker profiles, electromyography of his deltoid muscle, and magnetic resonance imaging, he was finally diagnosed as having paraneoplastic dermatomyositis. Accordingly, treatment with intravenously administered corticosteroid pulse treatment, immunoglobulin injection, and tacrolimus was applied; his symptoms subsequently improved. However, to our regret, at day 142 after administration, he died due to rapid worsening of his gastric cancer.
Differentially diagnosing paraneoplastic dermatomyositis or drug-associated myositis caused by immune checkpoint inhibitors is difficult in some cases. The differential diagnosis is crucial because it influences the decision regarding the appropriateness of the use of immunosuppressive treatment against the autoimmune diseases as well as the decision regarding the appropriateness of the continuous use of immune checkpoint inhibitors against the primary cancers. Because subclinical autoimmune disease may become overt after administering immune checkpoint inhibitors, non-apparent autoimmune diseases, which have already existed, should also be considered to avoid the delay of appropriate treatment, when symptoms of autoimmune diseases are recognized.
虽然皮肌炎常与恶性肿瘤相关，但免疫检查点抑制剂可引发多种自身免疫性疾病，如肌炎。鉴别诊断恶性肿瘤相关皮肌炎或免疫检查点抑制剂所致肌炎有时颇具难度，尤其是恶性肿瘤患者在使用检查点抑制剂后出现肌炎症状时。我们就遇到过这样一例难以诊断副肿瘤性皮肌炎或药物相关性肌炎的病例。在该病例中，我们团队最初均认为诊断为免疫检查点抑制剂所致肌炎。然而，最终确诊为副肿瘤性皮肌炎。鉴于诊断出乎意料，故在此报告。
我们报告一例71岁日本男性病例，其在接受纳武单抗治疗胃癌后出现肌炎临床症状，如肌肉疼痛和无力。他最初被诊断为纳武单抗诱导的肌炎，因为肌炎症状在纳武单抗给药后出现，且已知纳武单抗会引发各种药物相关性自身免疫性疾病。然而，根据其特征性皮肤病变、肌无力类型、血清标志物谱、三角肌肌电图及磁共振成像，最终诊断为副肿瘤性皮肌炎。因此，采用静脉注射糖皮质激素冲击治疗、免疫球蛋白注射及他克莫司治疗；其症状随后有所改善。然而，遗憾的是，给药后第142天，他因胃癌迅速恶化而死亡。
在某些情况下，鉴别诊断副肿瘤性皮肌炎或免疫检查点抑制剂所致药物相关性肌炎存在困难。鉴别诊断至关重要，因为它会影响针对自身免疫性疾病使用免疫抑制治疗的适宜性决策，以及针对原发性癌症持续使用免疫检查点抑制剂的适宜性决策。由于免疫检查点抑制剂给药后亚临床自身免疫性疾病可能会显现，当识别出自身免疫性疾病症状时，也应考虑已存在的隐匿性自身免疫性疾病，以免延误适当治疗。
