In this patient, what is the likely primary? What are other possible primaries?
Given the demographics and bilateral breast prostheses and mixed lytic / sclerotic bone lesions breast carcinoma is most likely. Other primaries to be considered are ovarian cancer, gastric cancer, colorectal cancer, gallbladder carcinoma, pancreatic carcinoma, lung cancer, and malignant melanoma, although most of them can be almost discounted given the presence of normal appearing large bowel, gallbladder, and pancreas.
Extensive fluid is seen in the peritoneal cavity associated with thickening of the peritoneum which enhances and appears nodular in places. The omentum, located anteriorly and to the left of the midline, appears stranded and bulky with multiple nodular regions of soft tissue density.
Nodular pleural thickening is noted on the left, and bilateral breast prostheses in situ. On the right side of the T12 vertebral body, involving the posterior vertebral body and right pedicle, is a region of mixed sclerosis and lysis. Similar other regions are present elsewhere in the spine (confirmed on bone window - not shown).