Eighty-five cases with secondary malignant disease of bone were reviewed to confirm their primary source. Primary source was fairly easily detected in 50 cases of patients with known malignant disease in their histories.
Difficulty arised when a bone lesion was detected clinically and radiologically, but no primary source was known. Many kinds of investigation were performed to discover the primary lesion; scanning with radio-isotope in 9 cases, bone biopsy in 9 cases, organ biopsy in 6 cases and necropsy in 3 cases.
As the result, the primary lesion was confirmed in 59 cases, but remained unknown in 26 cases.
