Pathology of human organic mercury poisoning: Lessons from an autopsy case

We had an opportunity to perform a general autopsy of a case with chronic organic mercury toxicosis in 2017. He had been engaged in synthesizing a variety of organic mercury compounds throughout the four years from 1966 and developed chronic organic mercury poisoning in 1969. Almost forty years on, he still remained to complain of persistent paresthesia at finger tips and tongue, and of narrowed visual field. Neurological examinations clarified a rise of two-point discrimination thresholds, a systemic increase of touch thresholds, constriction of the visual field caused by general visual depression, and sensorineural hearing loss while primary modalities of his somatic, visual, and auditory sensations were preserved. These symptoms and signs are characteristic of human organic mercury poisoning. Furthermore, he had difficulty in processing a lot of visual and auditory information at a time. His two-point discrimination thresholds and systemic elevation of touch thresholds were comparable to those of mild organic mercury poisoning cases. He had slight sensory ataxia, but not cerebellar ataxia. Brain [18F]-2-fluorodeoxyglucose positron emission tomography analysis exhibited marked hypometabolism at bilateral postcentral gyrus, striate cortex, and superior temporal gyrus, but not the cerebellum. Histopathological studies revealed considerable decrease of granular neurons and neuronal networks in bilateral primary somatosensory, visual, and auditory cortices. Those characteristic brain lesions fairly explain increase of thresholds of somatic, visual, and auditory sensations, and degradation of integrating sensory information. It is noted that damages to the peripheral nervous system and the cerebellum were not detected and that his intellectual faculties were preserved.

The life-threatening rash of poisoning

Dermatology is frequently viewed by physician and surgical colleagues as a specialty with few emergencies. Although the majority of dermatology practice is in the office setting, cutaneous emergencies do occur through referrals from primary care and as ward consults. Even though cutaneous signs of poisoning would be an uncommon emergency consultation, it is important for dermatologists to be aware of the clinical presentations so as to be able instigate appropriate time critical treatments.

Lung Function Assessment as an Early Biomonitor of Mercury-Induced Health Disorders in Artisanal and Small-Scale Gold Mining Areas in Indonesia

The evaluation of mercury impact on humans is currently nonspecific because the body characteristics (homeostasis) of each human being varies. Therefore, in the early diagnosis of mercury toxicity, one of the most important monitoring parameters is the respiratory function examination. In this study, respiratory function was examined with a portable spirometer and correlated with the mercury levels in hair from the noses and heads of subjects. Samples were taken from artisanal and small-scale gold mining (ASGM) areas (villages of East Tulabolo and Dunggilata) and control areas (villages of Bongo and Longalo) in Gorontalo Province, Indonesia. A statistical analysis with the Mann⁻Whitney test (alternative) showed significant differences in lung function between the polluted and control areas (α = 0.03). The analysis of nasal and head hair samples with particle-induced X-ray emissions (PIXE) showed that the mercury levels in the ASGM area were considerably higher than in the more homogeneous control areas. This study confirms that a pulmonary function test is a quick and precise alternative way to monitor the impact of mercury on humans, especially atmospheric mercury, because we detected a negative correlation between pulmonary function and the level of mercury in hair.

Acute mercury exposition of virgin, pregnant, and lactating rats: Histopathological kidney and liver evaluations

This work investigated the effects of mercury chloride (HgCl₂ ) acute exposure on virgin, pregnant and lactating rats by determination of renal and hepatic morphological and ultrastructural parameters and the expression of oxidative stress and stress tolerance markers, due to kidney and liver are the organs that more accumulate inorganic mercury. Adult Wistar rats virgin (90 days old), pregnant (18^th gestation day) and lactating (7^th lactation day) were injected once with HgCl₂ (5 mg/kg) or saline (controls). We observed that HgCl₂ exposure of virgin rats caused significant inflammatory infiltration and severe morphological variations, like glomeruli atrophy, dilatation of Bowman's capsule, tubular degeneration and hepatocytes alteration. Moreover, virgin rats presented mitochondrial modification, important oxidative stress and increase in stress tolerance proteins at both kidney and liver level, compared with virgin controls. In detail, virgin rats exposed to HgCl₂ presented significantly elevated level of inducible nitric oxide synthase, heat shock protein 27 and glucose regulated proteins 75 expressions at both renal tubular and hepatocytes level, respect untreated virgin rats. Interestingly, pregnant and lactating rats exposed to HgCl₂ presented weak renal and liver morphological alterations, showing weak inflammatory infiltration and no significant difference in structural mitochondrial transmembrane protein, oxidative stress markers and stress tolerance proteins expressions respect controls (virgin, pregnant and lactating rats). Although, both control and HgCl₂ -exposed pregnant and lactating rats showed renal glomeruli greater in diameter respect virgin rats. In conclusion, we believe that virgin rats are more sensitive to HgCl₂ toxicity respect pregnant and lactating rats. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1500-1512, 2017.

Ultrastructural Demonstration of Mercury Granules in the Placenta of Metallothionein-Null Pregnant Mice after Exposure to Mercury Vapor

The placenta plays an important role in the regulation of maternal to fetal transfer of toxic substances, including nonessential metals. Metallothioneins (MTs), which are known to have protective effects against heavy metal toxicity, exist in the placenta, but the exact localization of placental MTs (both MT-I and MT-III) and their physiological role in the placenta exposed to mercury are unclear. The present study was performed to examine the localization of MTs and mercury granules in the placenta of mice exposed to mercury vapor. On gestational day 16, MT-I & II-null and wild-type mice were exposed to mercury vapor at 4.9 to 5.9 mg/m3 for 2 hours. At 24 and 48 hours after exposure, the placentas were examined for mercury distribution (autometallography), MT immunoreactivity, and MT mRNA expression (in situ hybridization). No histological changes were observed in the placentas of either MT-null or wild-type mice. Mercury deposition was demonstrated along the boundary between the junctional zone and the labyrinth zone, as well as in the yolk sac, maternal decidual cells, and labyrinth trophoblasts of both MT-null and wild-type mice. MT-I & -II immunoreactivity, which was confined to wild-type mice, was demonstrated in the yolk sac and decidual cells; mercury was also shown in both structures, suggesting that mercury granules were bound to MTs. MT-III mRNA expression was observed in the yolk sac, decidual cells, and spongiotrophoblasts in both MT-null and wild-type mice. There was, however, no evidence of MT at the boundary between the junctional and labyrinth zones, where substantial mercury deposits were demonstrated. These results suggest that placental MTs and the other unknown molecules may be related to the barrier to the placental transfer of mercury.

Mercury induced haemocyte alterations in the terrestrial snail Cantareus apertus as novel biomarker

The aim of the present work was to study the response of a suite of cellular and biochemical markers in the terrestrial snail Cantareus apertus exposed to mercury in view of future use as sensitive tool suitable for mercury polluted soil monitoring and assessment. Besides standardized biomarkers (metallothionein, acetylcholinesterase, and lysosomal membrane stability) novel cellular biomarkers on haemolymph cells were analyzed, including changes in the spread cells/round cells ratio and haemocyte morphometric alterations. The animals were exposed for 14 days to Lactuca sativa soaked for 1h in HgCl2 solutions (0.5 e 1 μM). The temporal dynamics of the responses were assessed by measurements at 3, 7 and 14 days. Following exposure to HgCl2 a significant alteration in the relative frequencies of round cells and spread cells was evident, with a time and dose-dependent increase of the frequencies of round cells with respect to spread cells. These changes were accompanied by cellular morphometric alterations. Concomitantly, a high correspondence between these cellular responses and metallothionein tissutal concentration, lysosomal membrane stability and inhibition of AChE was evident. The study highlights the usefulness of the terrestrial snail C. apertus as bioindicator organism for mercury pollution biomonitoring and, in particular, the use of haemocyte alterations as a suitable biomarker of pollutant effect to be included in a multibiomarker strategy.

Mercury toxicity presenting as acrodynia and a papulovesicular eruption in a 5-year-old girl

Acrodynia is a reaction that occurs in children who have been exposed to mercury. Mercury toxicity has systemic manifestations as well as cutaneous manifestations, which can appear similar to those found in a number of other diseases. We present a case of acrodynia caused by mercury exposure in a previously healthy 5-year-old girl who developed hypertension, palmoplantar pruritus, and a papulovesicular eruption.

Health concerns of heavy metals and metalloids

There is a long history and an overwhelming amount of data on the toxicity of heavy metal compounds. Here a brief look is taken of some aspects of the toxicity of lead, cadmium, mercury and arsenic, chosen for their historical importance and environmental significance, highlighting especially the contrast between the acute and chronic toxicity of purely inorganic species and their organic derivatives. For further details of other toxic metal compounds, the reader might like to consult "Elements of murder: a history of poison" by John Emsley (2005, Oxford University Press).

Cutaneous mercury granuloma: a case report

Cutaneous mercury (Hg) granuloma is a rare disorder caused by the traumatic introduction of elemental Hg into skin or soft tissue. Typically, cutaneous elemental Hg deposits cause limited systemic effects. Prominent systemic toxicity may, however, occasionally occur. Herein we report a case of cutaneous Hg granuloma resulting in chronic painful local wounds and systemic toxicity in the form of abdominal pain, visual disturbances, and psychiatric abnormalities. The related literature also is reviewed.

[Morphologic and neurochemical effects in long-term period of mercurial intoxication (experimental data)]

The article deals with influence of longstanding inhalation of mercurial vapors on behavior of white rats, on morphologic and functional disorders in nervous system, on peculiarities of neuromediators metabolism in brain homogenate over the post-contact period.

A Child with Elemental Mercury Poisoning and Unusual Brain MRI Findings

Mercury vapor poisoning is a serious and potentially fatal problem. Neurological manifestations involving the central nervous system are seen with chronic mercury intoxication. We present the case of a 10-year-old child who demonstrated acrodynia, seizures, and visual impairment following 20 days of exposure to elemental mercury at home. The initial blood mercury concentration was 27.7 microg/L (normal <2 microg/L) and the initial 24-hour urine mercury concentration was 34.4 microg/L (normal =10 microg/L). After 9 months of treatment with D-penicillamine, the patient's clinical condition, biochemical laboratory parameters, and mercury concentrations all returned to normal. The T2-weighted MRI images of the patient's brain initially showed multiple hyperintense lesions in cerebral white matter, left globus pallidus, and putamen, which also improved.

Cellular responses in the cyprinid Leuciscus cephalus from a contaminated freshwater ecosystem

The response of wild chubs (Leuciscus cephalus) to chemical pollution was assessed in a metal contaminated river (Cecina River, Italy) through a wide battery of biomarkers which included: Comet assay detecting DNA strand breaks; diffusion assay for apoptosis induction; micronucleus test assessing chromosomal alterations; ethoxyresorufin O-deethylase (EROD) activity for the induction of cytochrome P 4501A; acetylcholinesterase (AChE) activity responsive to pesticide exposure; vitellogenin gene expression in males revealing estrogenic effects. Bioaccumulation of mercury, chromium and polycyclic aromatic hydrocarbons (PAHs) was also determined. Levels of mercury and PAHs were higher in tissues of chubs sampled from the most downstream station, reflecting an anthropogenic pollution of industrial origin. Otherwise, accumulation of Cr was quite similar in fish along the entire course of Cecina River confirming a natural origin due to local geochemical features. Biomarker responses revealed a significant increase of apoptotic cells, DNA stand breaks and micronucleus frequency in chubs from the more impacted sites. A slight EROD induction and AChE inhibition were only seen at the most downstream station demonstrating a limited impact due to PAHs and pesticides. On the other hand, the induction of vitellogenin gene in male chubs was measured in all the sites, suggesting a diffuse estrogenic effect. This study confirmed the utility of large batteries of biomarkers in biomonitoring studies and the suitability of wild chub as bioindicator organism for river basins.

Comparative evaluation of the protective effect of selenium and garlic against liver and kidney damage induced by mercury chloride in the rats

The present study was designed to compare the protective effect of selenium and garlic against liver and kidney damage induced by (ip) injection of 0.5 mg/kg mercury chloride (HgCl(2)) in rats. Thirty-six Sprague-Dawley rats were used in the present experiment and divided into six groups: one group was orally given (1 ml) saline and served as a control group; two groups of rats were given either selenium (0.1 mg/kg) or garlic (63 mg/kg) alone, once daily an oral dose for 30 successive days; other two groups of rats were given either selenium or garlic alone, once daily a dose for 15 successive days prior to HgCl(2) injection and on the next 15 successive days simultaneously with HgCl(2) injection; and the last group of rats was injected ip with HgCl(2) for 15 days and at the end of the experiment (which lasted 30 days), blood samples for the biochemical analysis were obtained from all rats after being lightly anesthetized with ether, and specimens of kidney and liver were removed and prepared for histochemical study. Computer image analysis was applied to liver and kidney tissues to evaluate the DNA density and DNA ploidy pattern in different groups. The results revealed that the rats injected with HgCl(2) showed a significant increase in levels of blood urea nitrogen (BUN), serum creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST) by 29.3%, 62.5%, 29.46% and 30.61%, respectively, while alkaline phosphatase (ALP) showed a significant decrease by 22.6% as compared with saline control group. Rats that were given selenium in combination with the HgCl(2) injection showed a significant decrease in BUN, Serum creatinine, ALT and AST levels, while ALP was significantly increased as compared with HgCl(2) group. Also rats that were given garlic in combination with HgCl(2) injection showed a significant decrease in BUN, Serum creatinine, ALT and AST levels, although serum ALP level showed an increase as compared to HgCl(2) group. Rats that had been orally administered selenium or garlic alone did not show any significant changes in the serum level of BUN, Serum creatinine, ALT and AST but there was a significant decrease in ALP level as compared with saline control group. The cytometric results revealed that injection of HgCl(2) induced an increase in the DNA density in kidney tissues with an increase in aneuploid cells and decrease in diploid cells. However, DNA density decreased in liver tissues with mild decrease in diploid cells and little percentage of aneuploid cells. We can conclude that oral administration of either selenium or garlic produces a significant protection against liver and kidney damage induced by the HgCl(2) injection, but garlic appears to be more protective.

ALS and mercury intoxication: A relationship?

We report the case of an 81-year-old woman in whom clinical signs and features of electromyographic activity patterns were consistent with amyotrophic lateral sclerosis (ALS). Increased blood level and massive urinary excretion of mercury proved mercury intoxication. Despite a chelation treatment with Meso 2-3 dimercaptosuccininc acid (DMSA), she died after 17 months. The pathophysiology of sporadic ALS remains unclear. However, the role of environmental factors has been suggested. Among some environmental factors, exposure to heavy metals has been considered and ALS cases consecutive to occupational intoxication and accidental injection of mercury have been reported. Although no autopsy was performed, we discuss the role of mercury intoxication in the occurrence of ALS in our case, considering the results of experimental studies on the toxicity of mercury for motor neuron.

Effect of monothiol along with antioxidant against mercury-induced oxidative stress in rat

Efficacy of thiol chelators viz. N-acetyl cysteine and D-penicillamine (NAC and DPA) along with nutritional supplements viz. zinc acetate, sodium selenite and magnesium sulphate (Zn, Se and Mg) in the treatment of mercury intoxication was investigated in rats. This is of particular interest since high bonding affinity between mercuric ion and the thiol group exits. The mutual antagonism of mercury and selenium is one of the strongest examples of the interaction in the trace element field. Adult rats of Sprague-Dawley strain were administered a bolus dose of dimethyl mercury (10 mg/kg) orally. A significant rise in the aspartate aminotransferase, alanine aminotransferase, serum alkaline phosphatase, lactate dehydrogenase, gamma glutamyltranspeptidase, bilirubin and creatinine were observed. Single mercury exposure also resulted in a significant increase in lipid peroxides with a concomitant decrease in reduced glutathione level in liver, kidney and brain. A decrease in the enzymatic activities of acetyl cholinesterase in different regions of the brain was observed. These parameters were restored considerably with chelating agents along with nutritional supplementation, but NAC+Se and DPA+Mg offered significant protection in comparison with other combinations.

Elemental mercury poisoning probably causes cortical myoclonus

Mercury toxicity causes postural tremors, commonly referred to as "mercurial tremors," and cerebellar dysfunction. A 23-year woman, 2 years after injecting herself with elemental mercury developed disabling generalized myoclonus and ataxia. Electrophysiological studies confirmed the myoclonus was probably of cortical origin. Her deficits progressed over 2 years and improved after subcutaneous mercury deposits at the injection site were surgically cleared. Myoclonus of cortical origin has never been described in mercury poisoning. It is important to ask patients presenting with jerks about exposure to elemental mercury even if they have a progressive illness, as it is a potentially reversible condition as in our patient.

Baboon syndrome induced by mercury - first case report in China

A case of mercury-induced baboon syndrome was reported. A 31-year-old woman presented with itching papules and vesicles in the right axilla, which extended to the left axilla, arms, fossa poplitea, buttocks, and groin. A mercury thermometer was broken 2 days before exanthema. Patch testing to ammoniated mercury, mercury, mercuric chloride, and mercurochrome were positive. Blood and urine mercury level was marginally normal, yet showed a descending trend over time.

Toxic effects seen in a herd of beef cattle following exposure to ash residues contaminated by lead and mercury

Lead poisoning was diagnosed in three cattle along with increased mercury levels in the liver and kidney tissues of two of these animals. The clinical signs were different in each case and included salivation, anorexia, delayed menace response, delayed withdrawal reflex, head pressing, localized muscle fasciculation, reduced tongue tone, ataxia, rumen atony and seizures. Blood lead concentration was increased in all three cases to 0.76, 0.37 and 0.454ppm. Post mortem changes characteristic of lead poisoning were only recognized in one case and included cerebro-cortical oedema, cortical neuronal necrosis and endothelial proliferation, especially at the tips of the cerebral gyri. The animals were poisoned by ingestion of lead-contaminated ash residues from a bonfire. The abnormal levels of mercury in the liver and kidney tissues of two animals may also be at least partly attributable to the intake of the metal in the ash residues. The levels of mercury in the three samples from the ash residue were relatively low (1.31, 0.7 and 2.1ppm).

Modulating effects of dietary fats on methylmercury toxicity and distribution in rats

Fish consumption is the most important source of human exposure to methylmercury (MeHg). Since fish is also a rich source of n-3 polyunsaturated fatty acids, this study was conducted to examine the effects of dietary fats on MeHg-induced acute toxicity in rats. Weanling male Sprague Dawley rats were administered semi-purified casein-based isocaloric diet containing soy oil, seal oil, docosahexaenoic acid (DHA), fish oil, or lard for 28 days. Rats were then gavaged with 0, 1, or 3 mg MeHg/kg body weight (BW) per day and fed the same diet for 14 consecutive days. On 43rd day of the experiment, rats were sacrificed and blood samples were collected and analyzed for hematology. Liver and spleen were removed, fixed, and examined for pathological changes. Blood, feces, liver, and brain were analyzed for total mercury and/or MeHg contents. Serum samples were analyzed for clinical markers of hepatic injury and immunoglobulin. Total mercury contents in all tissues measured increased with dose. Mercury excretion in feces increased with dose and duration of MeHg treatment. Both diets and MeHg showed significant effects and interacted significantly on many of the toxicological endpoints measured. Many of the effects of MeHg were diet-dependent. For example, in the rats fed the lard diet, 3mg MeHg/kg BW significantly increased relative liver and spleen weight as compared with vehicle control; whereas in rats fed the fish oil, soy oil, seal oil, or DHA, this effect of MeHg was less obvious or absent, suggesting a protective effect of these diets. MeHg at 3mg/kg BW significantly decreased serum albumin level in all except DHA dietary groups, implying a protection by the DHA diet on this parameter. Only in the lard dietary group, did 3mg MeHg/kg BW significantly increase serum bilirubin level, indicating an enhancing effect of this diet on MeHg toxicity. MeHg suppressed the adaptive immune system and stimulated the innate immune system in rats in a diet-dependent fashion. The seal oil diet provided more resistance, while the fish oil diet rendered greater sensitivity to these effects of MeHg on the immune system. These results imply significant modulating effects of dietary fats on MeHg toxicity which may translate into more severe or protective clinical outcomes. Therefore, dietary fats are important factors to be considered in the risk assessment of MeHg exposure.

[Long-term survival after a suicidal intravenous injection of mercury]

The authors present extraordinary autopsy findings, i.e. metallic mercury deposits within the cardiac muscle of a 28-year-old deceased of a male sex. Eleven years previously, the man had injected metallic mercury to the vein in the elbow region with a suicidal intent. Eighteen months later, during diagnostic management of dyspnea, metallic deposits in various internal organs had been revealed and a case history of the patient was published. Subsequently, the patient failed to report for follow-up examinations, and finally, committed suicide by hanging.

Cutaneous poisoning syndromes in children: a review

PURPOSE OF REVIEW

The purpose of this article is to review cutaneous poisoning syndromes in the pediatric population and to describe the diagnostic and therapeutic challenges in the management of these conditions.

RECENT FINDINGS

In recent years, the American Academy of Pediatrics and the Center for Disease Control have been continuously monitoring the lowest blood levels of numerous elements and nutrients associated with the slightest degree of toxicity. This review will focus on the clinical presentation, recognition and management of poisoning with cutaneous manifestations such as carotenoderma, mercury, dioxin and arsenic poisoning.

SUMMARY

Despite numerous efforts of federal and local government agencies to decrease poisoning incidents among consumers, sporadic cases of cutaneous poisoning still arise. Pediatricians should be familiar with the clinical presentation of various toxic syndromes and, more importantly, be able to teach prevention during regular medical encounters.

Short-Interfering RNA-Mediated Silencing of Thioredoxin Reductase 1 Alters the Sensitivity of HeLa Cells toward Cadmium

The mammalian thioredoxin reductase (TrxR) is a selenocysteine-containing flavoprotein that regulates the thioredoxin system, one of the major systems that maintain the intracellular redox balance. We previously reported that cytosolic TrxR (TrxR1), one of three mammalian TrxR isozymes, was induced by treatment with cadmium. In the present study, to study the role of cadmium-induced TrxR1 in cellular defense, we silenced the expression of TrxR1 in HeLa cells by using small interfering RNA and examined the effect of TrxR1 silencing on the sensitivity of the cells toward cadmium. We found that the gene silencing of TrxR1 had a dual effect on cadmium-induced cell death, depending on the concentration of cadmium. The TrxR1 silencing increased the sensitivity toward a low dose (less than 10 microM) of cadmium but decreased the sensitivity toward a high dose of cadmium. These results suggested that TrxR1 might play an important role in the cellular defense system against cadmium in two ways. TrxR1 might rescue the cells from a low dose of cadmium-induced moderate injury, while it might promote the death of cells severely injured by a high dose of cadmium.

FT-IR Study of the influence of Tribulus terrestris on Mercury intoxicated mice, Mus musculus liver

FT-IR spectra of liver tissue isolated from mice, Mus musculus, have been recorded in the region of 4000 - 400 cm-1 for normal, mercury treated and recovery phase. In this study, the total protein content was found to be decreased in the liver tissues after treatment with median-lethal dose of mercuric chloride. The marked fall in the level of bio-chemical constituent in the tissue due to metal exposure indicates the rapid initiation of the breakdown of the bio-chemical constituents to meet the energy demand during toxic stress. During the recovery phase, the decreased levels of bio-chemical constituents are restored to near normal level. Methanol fractions of Tribulus terrestris fruit extract was administrated on mercury intoxicated mice for 15 days. After the administration, the mercury-intoxicated animals slowly recovered from the adverse effect of mercury poisoning with the help of plant bio-formulations. The results are discussed in detail.

Case report: subcutaneous elemental mercury injection--clinical observations and implications for tissue disposal from the histopathology laboratory

A 31-yr-old man presented to his general physician complaining of pain and swelling in the soft tissue of both hips. He initially denied knowledge of the etiology, but after elemental mercury droplets were expressed from the skin wounds by manual manipulation, he admitted that the source was self-administered sc injections. He did not provide a reason for this or give the time-frame of the injections. The areas of skin discoloration and soft tissue induration were completely excised and the wounds healed uneventfully. Blood levels of mercury declined gradually after excision. Examination of the resected skin and subcutis revealed subcutaneous abscesses containing droplets of elemental mercury, released easily when the abscesses were sectioned. Sections showed dark droplets of metallic mercury associated with necrosis and microabscess formation, with areas of foreign body giant cell reaction. Disposal of the residual tissues and mercury by incineration would release the volatile elemental mercury into the atmosphere, where it would subsequently be returned to earth in rain water, be converted to methyl mercury by microorganisms, and enter the food chain. The US Environmental Protection Agency has recommended caution in consuming foods containing methyl mercury and has provided guidelines for consuming foods believed to contain increased amounts of mercury. Mercury is readily available in the United States by over-the-counter sales to consumers, and in some cultures elemental mercury is used in ritualistic practices. Skin injection cases are infrequent, but histopathology laboratories should recognize this phenomenon and be prepared to dispose of Hg-contaminated tissues in an environmentally sound manner.