Tc-99m MDP and Tc-99m MIBI in the assessment of spondyloarthritis presenting as bone metastasis before treatment with infliximab.

A 47-year-old man with seronegative spondyloarthritis presented with low back and chest pain with tenderness over the sacroiliac joints and the left ischial tuberosity. A bone scan revealed multiple areas of increased uptake suggestive of metastatic disease. However, the clinical impression corresponded with an inflammatory cause, and this was verified by findings of no increased uptake in all lesions on Tc-99m MIBI. A bone scan repeated after treatment with the immunomodulating agent, Infliximab, showed remarkable improvement The value of Tc-99m MDP in the assessment of disease-modifying treatment and the negative predictive value of Tc-99m MIBI in excluding skeletal malignancy are well established in this case.