Mucocutaneous pigmented macule as a result of zinc deposition

Mucocutaneous depositions of various metals such as silver, lead, gold, arsenic, mercury, iron, and bismuth have been previously published. Heavy metal deposition typically occurs in the setting of either prolonged topical application to intact skin, topical application to eroded or ulcerated skin, as a result of either parenteral administration, or due to penetrating traumatic exposure.

We report a unique case of mucocutaneous pigmentation occurring in a snow skier after topical application of a zinc-containing sunblock. Formalin-fixed paraffin-embedded tissue was utilized for electron microscopy.

Backscatter electron imaging and energy dispersive spectroscopy revealed that the dominant metal present was zinc.

Mucocutaneous deposition of metals is enhanced by damage to the surface epithelium. Metal-containing topical agents, although commonly used, may rarely result in a permanent pigmentary alteration. We believe similar cases of mucocutaneous deposition of zinc exist; however, as these may be currently misdiagnosed as amalgam tattoos, the true incidence of this disorder is presently undefined.