Presentation
Abdominal pain
Patient Data
Mixed sclerotic and lytic appearance to a large region of the right hemipelvis, particularly the ischium. More discrete foci of medullary sclerosis seen within the proximal femora, left iliac bone, right sacral ala and left anterior aspect of the L5 vertebral body. The patient had a known history of prostate cancer with the appearance being in keeping with prostate cancer osseous metastases.
Note that the relative lucent areas within the diseased right hemipelvis still show a high density (170 HU) compared to the normal medullary fat on the contralateral side (-38 HU). This helps differentiate metastasis from Paget disease, as the former produces loss of the normal medullary fat density while the latter will typically demonstrate preserved fat density within the lucent areas.
Case Discussion
A case of prostate cancer osseous metastases somewhat simulating the appearance of right hemipelvis Paget disease. Given how common Paget disease is, it could be easy for the inexperienced or rushed reader to quickly ascribe the right hemipelvis bony abnormality to Paget disease. The lack of cortical thickening and the lack of medullary fat preservation, along with the presence of multiple other more discrete sclerotic bone lesions, are the major clues to making the correct diagnosis of osseous metastases.