Detection of elemental mercury in abdominal wall soft tissue

A 19-year-old male with an unremarkable medical history presented with his father, who requested an evaluation of a pathology specimen from a reported "lump" under the skin in the middle of the son's lower abdomen. The lump had been excised by a surgeon approximately 3 months prior, per parental request. Upon gross inspection, the specimen appeared to contain small metallic droplets. The patient denied self-injection of any metals, including mercury, despite the results of a 24-hour urine heavy-metal screen (without chelation) that revealed an elevated concentration of mercury (87.6 microg/g creatinine; reference range for nonexposed adults: <4 microg/g creatinine). Confirmatory analysis of the tissue sample included gross and microscopic examination, electron microscopy using secondary and backscattered electron imaging modes, and energy dispersive x-ray spectrum analysis of isolated tissue particles. Grossly, the tissue had small silver spherules suggestive of elemental mercury; these droplets were identified histologically with associated foreign body reaction. Numerous smooth, round-to-oval particles scattered randomly throughout the tissue were identified ultrastructurally, which produced an x-ray energy spectrum corresponding to mercury.

Elemental mercury is liquid at room temperature and may be injected into the body for recreational, psychiatric, and other purposes. Isolated cases of mercury injection following accidents with broken thermometers have been reported, as well as cases of elevated metallothionein concentration following human gingival amalgam tattoos.

In cases of surreptitious injection, histology and ultrastructural evidence may be used to confirm the presence of mercury.