Oncogenous osteomalacia and malignancy.

An example of oncogenous osteomalacia is described in association with the rate mesenchymal chondroblastoma. The tumour was characterized with a variety of immunohistochemical antibodies which confirmed its mesenchymal origin. Despite several surgical excisions of local recurrence, plasma 1,25-dihydroxyvitamin D3 concentrations (off treatment) indicate continued tumour activity and the continuing need for vitamin D therapy. This case and two others briefly discussed illustrate some of the difficulties in diagnosis and in achieving a cure in cases of oncogenous osteomalacia. Oncogenous osteomalacia in association with any malignant tumour is rare, there being eight previously recorded cases. Details of these cases are briefly reviewed for comparison. Despite undoubted malignancy our patient has survived 30 years from presentation indicating the benefits of aggressive surgical management.