Titanium Pigment and Yellow Nail Syndrome

I would like to add some comments about a study of 5 Brazilian patients with necropsy findings of titanium deposits in samples of liver, spleen, lungs, lymph nodes, and bone marrow [5] , but without any change, neither in color nor in the structure of the nails. The origin of deposits detected by studies utilizing common light and polarized microscopy was chronic intravenous injection of crushed propoxyphene hydrochloride tablets containing minerals like basic silicate of magnesium and calcium, in addition to titanium as excipients [5] . Moreover, the characterization of titanium pigment was based on the optical microscopy qualities of the mineral, which appears white with the reflected light, black with the transmitted light, and pink under polarized light [5] . Noteworthy was the lack of yellow nail changes, despite the chronic presence of titanium in the entire body. Interestingly, titanium was not found in the nails of healthy people who were exposed to titanium and gold [2] . The practical usefulness of the studies by Ataya et al. [1] and Decker et al. [2] is really unquestionable; however, the commented findings seem to suggest additional research to better clarify the mechanisms of YNS.