False Negative ^99mTc-Hydroxymethane Diphosphonate Three-phase Bone Scintigraphy and ^99mTc-besilesomab Scan in Detecting Tibia Osteomyelitis Concomitant with Necrotizing Fasciitis

We described a case of 51-year-old female patient presented with a right calf necrotising fasciitis (NF) where osteomyelitis (OM) was suspected. ^99mTc-hydroxymethane diphosphonate three-phase bone scintigraphy and ^99mTc-besilosomab scan failed to demonstrate classical features of OM. The final diagnosis was only made by isolating Acinetobacter sp. in both intra-operative bone and tissue cultures from below-knee amputation. As conclusions, the detection of lower limb OM by ^99mTc-besilosomab scan is not easy when there is concurrence overlying NF. The unusual three-phase bone scan finding of pericortical accumulation of tracer as an early sign of OM is highlighted in this case