A 73 year old female presented with pyrexia of unknown origin despite the use of antibiotics. She recently had a colonoscopic stent inserted to resolve a large bowel obstruction secondary to stage IV sigmoid colon cancer. The procedure was complicated by a perforation of the sigmoid colon and the need for Hartmann’s procedure. Urine and blood cultures were both clear however the white cell count was elevated. X rays of the chest and abdomen and CT of the abdomen and pelvis showed no sites of infection. A 99mTc-HMPAO labelled white blood cell scan was performed to localise the site of infection. The whole body and SPECT images showed patchy uptake consistent with the known liver metastases. Reduced bone marrow uptake was seen in the left hemipelvis and a patchy appearance in the right hemipelvis. The appearance of osteomyelitis could not be confirmed and a bone scan was performed. The blood pool images demonstrated hyperaemia in the region of the upper sacrum and superior iliac crests. The delayed images confirmed the presence of Paget’s disease involving the right and left iliac crests and the sacrum. CT confirmed these findings. This case demonstrates that conditions such as Paget’s disease, which displaces the marrow, may cause reduced uptake on a labelled white cell scan. The cause may be confirmed with other techniques, such as bone scans and x ray.