Biopsy of suspicious bone lesions in patients with a single known malignancy: prevalence of a second malignancy

The probability that a suspicious bone lesion in a patient with one known malignancy is actually due to a second, previously unknown primary malignancy has been reported to be 2-8%. We sought to determine this prevalence as well as that of benign diagnoses in a larger number of patients in a tertiary cancer center.

The medical records of 482 consecutive patients (254 women and 228 men) with only one known primary malignancy each (excluding nonmelanoma skin cancer) and who underwent biopsy of a suspicious bone lesion were retrospectively reviewed. The results of bone biopsy were classified as benign, metastasis of the known primary malignancy, due to a second primary malignancy, or nondiagnostic or indeterminate.

In 103 of 482 (21%) patients, bone biopsy results were benign, 316 (66%) were due to metastases of the known malignancy, 15 (3%) were due to a second malignancy, and 48 (10%) were nondiagnostic or indeterminate. Second malignancies included osteosarcoma (n = 4); soft-tissue sarcoma (n = 2); lymphoma (n = 2); plasma cell malignancy (n = 2); and lung cancer, thyroid cancer, renal cancer, chondrosarcoma, and carcinoma of unknown primary (n = 1 each).

In 3% of patients with one known malignancy and a suspicious bone lesion, the lesion was due to a previously unknown second malignancy; in 21% of patients, the lesion was benign. Bone biopsy is recommended in the management of patients with one known cancer and a suspicious bone lesion only if the presence of a second malignancy would alter clinical management.