Scintigraphic findings in patients with shoulder pain caused by interleukin-2

Interleukin-2 is receiving widespread interest as an immunotherapeutic agent in the treatment of certain cancers. Severe arthralgias recently have been reported as a significant side effect, and the cause of pain is unknown. Because interleukin-2 is an immune modulator, we reviewed the 99mTc-methylene diphosphonate scintigrams in nine patients who had developed shoulder arthralgias while receiving interleukin-2 for metastatic melanoma. In eight of the patients, the scintigrams showed diffuse increased uptake of radionuclide in the shoulders. Four patients had radiographs of their shoulders, all of which were normal. Bone scintigraphy in patients receiving interleukin-2 as immunotherapy for metastatic melanoma shows increased radionuclide activity in the shoulders. This process may relate to the role of interleukin-2 as a mediator in the inflammatory response.