Bone Scintigraphy in Pembrolizumab-Induced Inflammatory Arthritis.

We present a novel report on the use of bone scintigraphy in pembrolizumab-induced inflammatory arthritis. A 70-year-old man with lung cancer complained about arthralgia after 7 courses of the pembrolizumab therapy. Tc-HMDP bone scintigraphy revealed symmetrically strong uptakes in the major distal joints of the upper and lower extremities, thereby clearly identifying them as the affected joints. The pattern of uptakes was not consistent with that of other pathophysiologies including bone metastases, hypertrophic osteoarthropathy, and rheumatoid arthritis. Tc-HMDP bone scintigraphy is more practical and cost-effective compared with PET to reveal the affected joints in pembrolizumab-induced inflammatory arthritis.