Why do i black spots in my skull. revealed by a cat scan. bone marrow biopsy revealed no cancer?

DDx: I see a lot of multiple myeloma, so i think of lytic (punched out) lesions in the skull (calvarium) as myeloma. However other cancers such as squamous cell cancers (head/neck, lung, etc) can produce lytic lesions. Sometimes veins going through bone can produce "holes" that are normal. The differential diangosis (ddx) is broad -- eg http://www.Calvariallesions.Com/index.Html.