Extremely elevated serum alkaline phosphatase level upon treatment with teriparatide: a case report.

To the best of our knowledge, this is the first case of an osteoblast hyperactivation state observed during treatment with teriparatide. It appears that the osteoblastogenic effect of teriparatide might induce this condition and, most likely, osteosarcoma in certain populations. However, the potential influence of the patient's young age, systemic lupus erythematosus, underlying inherited connective tissue disease, and medication use cannot be ignored. The potential risk factors of this side effect shall be studied in specific subpopulations of patients with osteoporosis in future studies.