Usefulness of 201Tl and 99mTc MIBI scintigraphy in a case of oncogenic osteomalacia

A 45-year-old male was admitted with difficulty in walking due to leg pain. At the time of the first visit, a reduced serum phosphorus concentration and an increased serum alkaline phosphatase concentration of unknown etiology were observed. Either a whole body bone scintigraphy or CT of the neck, chest and abdominal region did not reveal any underlying disease. However both the whole body Tl-201 scintigraphy and Tc-99m MIBI SPECT showed accumulation in the right knee region, and a small tumor was detected by MRI examination. After a diagnosis of oncogenic osteomalacia due to this tumor was determined the tumor was surgically removed, and turned out to be a hemangiopericytoma. By removal of the tumor, either the symptoms or the laboratory data were improved significantly. In this case, both Tl-201 scintigraphy and Tc-99m scintigraphy MIBI were useful in identifying the location of the tumor which caused oncogenic osteomalacia.