Localization of 99mTc-methylene diphosphonate in skin lesions of pseudoxanthoma elasticum.

Increased uptake of 99mTc-methylene diphosphonate (MDP) is demonstrated in a patient with pseudoxanthoma elasticum (PXE) at the affected site. PXE is a hereditary disease with variable expression. Calification of dermal elastic fibers is a characteristic feature of affected skin. Recently, apatite crystals were identified in the affected skin of the patients with PXE. The mechanism of uptake of 99mTc-MDP is probably related to chemisorption of the tracer onto hydroxyapatite crystals in the affected dermis.