Osteopoikilosis is a rare, benign hereditary disease, which presents multiple osteosclerotic, and small round nodules in the bone. It is usually detected incidentally by radiological examination. A radionuclide bone scintigraphy is essential in distinguishing osteopoikilosis from osteoblastic metastases, because scintigraphic findings are usually normal in patients with osteopoikilosis. However, there have been no reports about F-18 fluorodeoxyglucose (FDG) PET findings in osteopoikilosis. Herein, we wish to report a case of osteopoikilosis with breast cancer, which could not be seen in either bone scintigraphy or F-18 FDG PET/CT.