Development of Remitting Seronegative Symmetrical Synovitis with Pitting Edema Syndrome with Pembrolizumab for Lung Squamous Cell Carcinoma

Abstract

Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs). There are a few case reports of remitting seronegative symmetrical synovitis with pitting edema syndrome (RS3PE) as an irAE. We herein report a 49-year-old Japanese man who developed acute-onset polyarthralgia and edema of the back of both hands and bilateral lower legs after pembrolizumab administration for lung cancer. The patient's lung cancer was in complete remission, leading to the diagnosis of RS3PE induced by pembrolizumab rather than malignancy. When patients show RS3PE during ICI treatment, rheumatologists should consider the possibility of an irAE after excluding malignancy and systemic diseases.

Keywords: immune-related adverse events; remitting seronegative symmetrical synovitis with pitting edema syndrome.

Figure 1.

Clinical course before the onset of remitting seronegative symmetrical synovitis with pitting edema syndrome.

Figure 2.

Clinical presentation of remitting seronegative symmetrical synovitis with pitting edema syndrome on admission (a, b) and after prednisolone therapy (c, d). (a, b) Pitting edema on the back of both hands and bilateral lower legs. (c, d) Two days after prednisolone therapy. Pitting edema completely disappeared.

Figure 3.

Image findings of ⁶⁷Ga scintigraphy (a, b) and musculoskeletal ultrasonography (c, d). (a) No accumulation suggestive of recurrence or metastasis of malignancy was noted in the whole body, including the right lung and mediastinal lymph nodes. (b) Mild accumulation in fingers and both hands. (c) Mild synovitis in the metatarsophalangeal joint. (d) Tenosynovitis was revealed by hypoechoic and power Doppler around the finger extensor tendon.

Figure 4.

Clinical course after the onset of remitting seronegative symmetrical synovitis with pitting edema syndrome.