Cutaneous amalgam tattoo in a dental professional: an unreported occupational argyria.

MADAM, Amalgam tattoo is the most common exogenous pigmentation of the oral mucosa; surprisingly, there are no reports of similar lesions on the skin. It is caused by traumatic implantation of amalgam fragments into the oral mucosa following dental treatment, particularly when amalgam fillings are removed with high-speed instruments. Amalgam tattoo occurs mostly in the gingiva and alveolar mucosa. Clinically it presents as an asymptomatic bluish to black macule, eventually observed by the patient or discovered during routine dental treatment. Histologically it shows brown to black aggregates of granules interspersed among collagen fibres and around blood vessels. Most cases show a slight inflammatory response, and eventually a foreign body granulomatous reaction is found. Cases of cutaneous localized argyria are uncommon, and are usually attributed to trauma, acupuncture, topical silver-based medication or use of pieces of jewellery such as earrings. We report a case of cutaneous amalgam tattoo caused by implantation of amalgam particles on the skin of the eyebrow of a dental surgeon. A 45-year-old female dental surgeon presented with a dark macule on the skin of the left eyebrow. She reported that it was probably associated with a traumatic lesion acquired 20 years previously when she was working as a dentist. The lesion was surgically removed, and histologically showed deposits of fine black granules among collagen fibres, involving the papillary and reticular dermis, surrounding cutaneous adnexa (hair follicles and sebaceous glands; Fig. 1a). The patient denied the use of acupuncture, topical silver-based medications or piercings. Considering the clinical history and histological picture, the diagnosis was of cutaneous amalgam tattoo. Scanning electron microscopy (SEM) of 5-lm unstained paraffin sections showed bright particles of about 1 lm long (Fig. 1c), and energy dispersive X-ray microanalysis (EDX) revealed silver as major element and sulphur as the second component (Fig. 2a). For comparison of histological and SEM aspects, we used a typical case of oral amalgam tattoo, obtained from our files, including EDX (Figs 1b, d and 2b). Histological, SEM and EDX results of the oral lesion were similar to those of the skin lesion, supporting the initial diagnosis of cutaneous amalgam tattoo. To our knowledge there are no reports in the literature of cutaneous amalgam tattoo, which is surprising because amalgam fragments can easily reach the dental surgeon during clinical procedures, especially if there is a lack of complete