Radionuclide bone images in hypertrophic pulmonary osteoarthropathy.

Hypertrophic Pulmonary Osteoarthropathy (HPO) can be differentiated from osseous metastasis on conventional bone images using technetium 99m radiopharmaceuticals. Periosteal new bone formation appears as symmetric circumferential deposition of radionuclide in the diaphyseal cortex of tubular bones. In contrast, asymmetrical deposits in the medullary canal are indicative of metastatic disease. The etiologies of hypertrophic osteoarthropathy are discussed.