Differentiating between benign and malignant bone lesions: The value of using SPECT/CT

Two cases are presented; in each case a patient with a known cancer history was imaged with combined single photon emission computed tomography (SPECT) and computed tomography (CT) to evaluate suspected bone pathology. While SPECT detected focal increased radiotracer uptake in the iliac bone in both patients, CT suggested a distinct etiology. In one case, the bone abnormality included lytic cortical bone destruction with soft tissue extending beyond the confines of the bone, consistent with osseous metastasis. In the other case there was loss of bone cortical integrity but an otherwise preserved cortical margin, lack of soft tissue involvement, and intralesional fat suggestive of a benign intraosseous lipoma. These two cases underscore the value of using hybrid imaging to distinguish benign from malignant bone disease; the structural details provided by CT were helpful to derive the diagnosis, potentially impacting patient management.