A Rare Case of Pembrolizumab-Induced Dermatomyositis in a Patient with Cancer of Unknown Primary Origin

Abstract

Patient: Female, 71-year-old Final Diagnosis: Dermatomyositis Symptoms: Fever • walking difficulties Medication: — Clinical Procedure: Corticosteroids Specialty: Immunology • Oncology • Rheumatology Objective: Rare disease Background: Pembrolizumab is a humanized monoclonal antibody against programmed cell death-1 protein. Pembrolizumab sometimes causes immune-related adverse events (irAEs). Dermatomyositis is a rare irAE of immune checkpoint inhibitors. The presentation is usually acute, and symptoms include edema with erythema of the eyelids, erythema of the forehead, and muscle weakness in both thighs. Case Report: Here we report a case of pembrolizumab-induced dermatomyositis in a 71-year-old Japanese woman with cancer of unknown primary origin, who experienced a high fever and had difficulty walking after her sixth course of pembrolizumab. General physical examination revealed edema with a heliotrope rash, V-neck signs, and non-specific erythema of the forehead. Laboratory evaluation revealed that myogenic enzymes were within normal ranges. Autoantibody tests revealed that antinuclear antibodies were negative, and autoantibodies related to myositis and anti-acetylcholine receptor antibodies were also negative. A magnetic resonance imaging scan of the thighs revealed signal abnormalities in the left lateral and distal vastus medialis muscle. The patient was treated with corticosteroids, subsequently followed by intravenous immunoglobulin therapy, which led to an improvement of the symptoms. Conclusions: Pembrolizumab-induced dermatomyositis is rare. Corticosteroids have been administered in many cases, and this case also suggests the efficacy of intravenous immunoglobulin therapy in treating immune checkpoint inhibitor-related dermatomyositis. This case highlights practical management of pembrolizumab-induced dermatomyositis.

Dermatomyositis Associated with Lung Cancer: A Brief Review of the Current Literature and Retrospective Single Institution Experience

“…Interestingly, to the best of our knowledge, there is only a single published case of DM that resulted in disease resolution following treatment with immunotherapy [ 32 ]. The large majority of cases report DM as an adverse effect of ICI (pembrolizumab -carcinoma of unknown origin, squamous cell carcinoma of lung and lung adenocarcinoma; atezolizumab-in small cell lung cancer and non-small-cell lung cancer; nivolumab- lung adenocarcinoma and ipilimumab- small-cell lung cancer) [ 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Bendewald et al have reported that the estimated incidence of DM is 9.63 cases per million people [ 22 ].…”

Drawbacks of Immune Checkpoint Inhibition and Rigorous Management for Immune Related Adverse Events Along with a Strategy Against Tumor Plasticity

“…One has to be very careful by presenting the onset frequency of irAEs, as the numbers vary widely in the literature each based on different study models with their own limitations [15][16][17][18][19][20][21][22][23][24][25][26][27].…”

“…It shall be noted that by presenting the approximate onset frequency for irAEs in The same is going to be valid for the next two tables, in which I will present approximate timing of some selected irAEs and related CTCAE grading peak in monotherapy and combination therapy applications, and approximate onset frequency of irAEs with respect to organ/tissue systems in a CTLA-4/PD-1 combination therapy scenario, respectively. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In Table 3, again the weeks refer to weeks after the initial infusion and the damping time is as explained for Table 2 above.…”

Management of Cancer-Associated Myositis

“…Although several authors have reported dermatomyositis patients with cancer in whom the disease flares after the therapy with checkpoint inhibitor [ 43 – 46 ], this is not always the rule, and studies addressed to a better definition of those patients in whom immunotherapy will be suitable are being conducted. But this is only one side of the coin, the other side refers to those patients with cancer who develop an immune-mediated myopathy soon after the onset of immunotherapy.…”