Wood dust and nasal cancer risk. A review of the evidence from North America

In this article, biomedical literature assessing risks of nasal cancer and nonmalignant nasal pathology among woodworkers in North America is reviewed in detail and contrasted with experience from Europe and elsewhere. Exceptionally high rates of nasal adenocarcinoma have occurred among European hardwood furniture workers, but the epidemiologic evidence documents a disparity in findings between North America and Europe. Cohort studies of American wood-dust-exposed groups do not reveal excesses of nasal cancer, and wood-dust associations from US and Canadian case-control studies of nasal cancer tend not to be strong and differ across studies. Quantitative wood-dust exposure data are generally unavailable, but general dose information in European studies suggests that the excess risk of nasal cancer is associated with high levels of exposure. There is also an inconsistent association between wood-dust exposure per se and mucostasis or nasal histologic changes, and the mucostasis/metaplasia/dysplasia route to nasal cancer is still an unverified hypothesis. Considering the totality of evidence on the risk of cancer in exposed workers, it appears that wood-dust-related nasal adenocarcinoma essentially can be eliminated in Europe and its occurrence prevented in the United States if wood-dust exposures do not exceed an 8-hour time-weighted average 5 mg/m3 standard.

Green tea consumption and the risk of pancreatic and colorectal cancers

The effect of green tea drinking in reducing human cancer risk is unclear, though a protective effect has been reported in numerous animal studies and several epidemiologic investigations. Herein the hypothesis that green tea consumption may reduce the risk of cancers of the colon, rectum and pancreas is examined in a large population-based case-control study conducted in Shanghai, China. Newly diagnosed cancer cases (931 colon, 884 rectum and 451 pancreas) during 1990-1993 among residents 30-74 years of age were included. Controls (n = 1,552) were selected among Shanghai residents and frequency-matched to cases by gender and age. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of each cancer associated with green tea consumption were derived after adjustment for age, income, education and cigarette smoking. Additional adjustment for dietary items and body size was found to have minimal impact. An inverse association with each cancer was observed with increasing amount of green tea consumption, with the strongest trends for rectal and pancreatic cancers. For men, compared with non-regular tea drinkers, ORs among those in the highest tea consumption category (> or = 300 g/month) were 0.82 for colon cancer, 0.72 for rectal cancer and 0.63 for pancreatic cancer, with p values for trend being 0.38, 0.04 and 0.04, respectively. For women, the respective ORs for the highest consumption category (> or = 200 g/month) were 0.67, 0.57 and 0.53, with the respective p values for trend being 0.07, 0.001 and 0.008. Our findings provide further evidence that green tea drinking may lower the risk of colorectal and pancreatic cancers.

Use of low molecular weight heparin in postangioplasty management

The results of using low molecular weight heparin (LMWH) in postangioplasty management are examined. In comparison to intravenous unfractionated heparin, subcutaneous LMWH caused less groin complications and was simpler and cheaper to be administered by the medical personnel. The incidence of ischaemic complications after angioplasty including acute closure and myocardial infarction, however, remained similar and was not excessive. Subcutaneous administration of LMWH provides and alternative simple and cost-effective strategy for postangioplasty management.

Reproductive factors, oral contraceptive use, and risk of colorectal cancer

Multiparity and use of oral contraceptives are hypothesized to reduce risk of colorectal cancer. Among 57,529 women, 31-90 years of age, who volunteered for a nationwide breast cancer screening program from 1973 to 1980, we observed 154 pathologically confirmed cases of colon cancer and 49 cases of rectal cancer in up to 10 years of follow-up (388,555 person-years). Parity was not associated with risk of colorectal cancer [age-adjusted rate ratio for > or = 4 children vs no children = 1.0; 95% confidence interval (CI) = 0.72-1.5], although decreases in proximal colon cancer and increases in distal colon cancer were observed among parous women. The effect of parity did not vary by age at diagnosis. We found no strong or consistent association for age at menarche, age at first birth, or age at natural menopause. In addition, oral contraceptive use, reflecting mainly past use, was unrelated to risk of colorectal cancer (rate ratio = 1.0; 95% CI = 0.75-1.4). These findings do not corroborate the hypothesis that reproductive events or oral contraceptives influence the development of colorectal cancer.

Mortality among benzene-exposed workers in China

A large cohort of 74,828 benzene-exposed and 35,805 nonexposed workers employed between 1972 and 1987 in 12 cities in China was followed to determine mortality from all causes. Benzene-exposed study subjects were employed in a variety of occupations including coating applications, and rubber, chemical, and shoe production. Mortality was slightly increased among workers with greater cumulative exposure to benzene (ptrend < 0.05), but this excess was largely due to cancer deaths (ptrend < 0.01). Deaths due to lymphatic and hematopoietic malignancies (ptrend = 0.01) and lung cancer (ptrend = 0.01) increased with increasing cumulative exposure to benzene. Investigations continue to relate benzene exposure to specific lymphatic and hematopoietic malignancies and other causes of death.

Indirect validation of benzene exposure assessment by association with benzene poisoning

We present a validation study of a quantitative retrospective exposure assessment method used in a follow-up study of workers exposed to benzene. Assessment of exposure to benzene was carried out in 672 factories in 12 cities in China. Historical exposure data were collected for 3179 unique job titles. The basic unit for exposure assessment was a factory/work unit/job title combination over seven periods between 1949 and 1987. A total of 18,435 exposure estimates was developed, using all available historical information, including 8477 monitoring data. Overall, 38% of the estimates were based on benzene monitoring data. The highest time-weighted average exposures were observed for the rubber industry (30.7 ppm) and for rubber glue applicators (52.6 ppm). Because of its recognized link with benzene exposure, the association between a clinical diagnosis of benzene poisoning and benzene exposure was evaluated to validate the assessment method that we used in the cohort study. Our confidence in the assessment method is supported by the observation of a strong positive trend between benzene poisoning and various measures, especially recent intensity of exposure to benzene.

An expanded cohort study of cancer among benzene-exposed workers in China. Benzene Study Group

An expanded cohort study of 74,828 benzene-exposed and 35,805 unexposed workers were followed during 1972 to 1987, based on a previous study in 12 cities in China. A small increase was observed in total cancer mortality among benzene-exposed compared with unexposed workers (relative risk [RR] = 1.2). Statistically significant excesses were noted for leukemia (RR = 2.3), malignant lymphoma (RR = 4.5), and lung cancer (RR = 1.4). When risks were evaluated by leukemia subtype, only acute myelogenous leukemia was significantly elevated (RR = 3.1), although nonsignificant excesses were also noted for chronic myelogenous leukemia (RR = 2.6) and acute lymphocytic leukemia (RR = 2.3). A significant excess was also found for aplastic anemia.

Tea and cancer: a review of the epidemiological evidence

Numerous recent reports of inhibition of carcinogenesis in experimental animals by tea or tea compounds raise the possibility that tea drinking may lower cancer risk in humans. Thus, studies around the world were reviewed to evaluate whether there is a consensus of epidemiologic evidence on the relation of tea drinking to cancer overall or to specific cancers. Ecological data suggest at most a modest benefit, since there is considerable international variation in tea consumption but generally small differences in cancer rates. More relevant case-control and cohort studies show mixed results. Detailed data from these studies on cancer risks according to amount and duration of tea intake are quite limited, and consistent dose-related patterns. have yet to emerge. Nevertheless, several investigations point to the possibility of lowered risks of digestive tract cancers among tea drinkers, especially those consuming green tea. Further research, particularly in population with wide ranges of tea consumption, is needed before definitive conclusions on tea's impact upon cancer risk can be reached.

Clinical features of hematopoietic malignancies and related disorders among benzene-exposed workers in China. Benzene Study Group

Previous occupational cohort studies of benzene-exposed workers have for the most part used only death certificates to validate diagnoses of workers developing leukemia and other hematopoietic and lymphoproliferative malignancies and related disorders (HLD). In a follow-up study of 74,828 benzene-exposed workers and a comparison group of 35,805 nonexposed workers from 12 cities in China, we sought to characterized clinicopathologically and to confirm diagnoses of all cases of HLD. Using medical records, laboratory hematology results, and histopathology, U.S. and Chinese expert hematopathologists, blinded to exposure status, carried out a detailed review using standardized evaluation forms. Key among the findings were a notable diversity of malignant and nonneoplastic hematopoietic and lymphoproliferative disorders, documentation of excess myelodysplastic syndromes among benzene workers, and widespread dyspoiesis involving all hematopoietic cell lines. As sophisticated clinicopathologic characterization and corresponding classification schemes for HLD become increasingly widespread, it is recommended that future epidemiologic investigations of benzene workers incorporate similarly detailed morphologic evaluation. In extending follow-up of this cohort of young workers, we will continue to use all available clinical, laboratory hematology, and pathology data as well as cytogenetic and biochemical markers to characterized various HLD outcomes. These careful surveillance mechanisms should also provide additional insight into carcinogenic mechanisms of benzene and allow comparison of the molecular pathogenesis of HLD induced by benzene versus chemotherapy, radiation, or other exposure.

Excess risk of primary liver cancer in patients with diabetes mellitus

BACKGROUND

Chronic infection with hepatitis B virus, alcohol consumption, and cirrhosis of the liver are recognized risk factors for primary liver cancer. A few, but not all, studies have suggested that diabetes mellitus also increases risk for this cancer.

PURPOSE

We conducted a population-based cohort study to analyze the risk of developing primary liver cancer and biliary tract (gallbladder, extrahepatic bile ducts, and ampulla of Vater) cancers among patients with diabetes.

METHODS

A cohort of 153 852 patients with a hospital discharge diagnosis of diabetes in the period from 1965 through 1983 was identified by use of the Swedish In-patient Register. Follow-up for these patients extended from the date of cohort entry through December 31, 1989. Incident cases of cancer during follow-up were identified through the Swedish Cancer Registry. To minimize the impact of selection bias, we excluded from the analysis patients who were diagnosed with liver and biliary tract cancers during the first year of follow-up. Standardized incidence ratios (SIRs) and their 95% confidence intervals (CIs) were computed by use of nationwide rates of liver and biliary tract cancers, adjusted for age, sex, and calendar year, for comparison.

RESULTS

During 1-24 years of follow-up, 819 incident cancers in the combined category of primary liver (n = 533) and biliary tract (n = 286) were identified in the cohort, yielding an overall SIR of 2.5 (95% CI = 2.3-2.6). The risk was higher in men (SIR = 3.2; 95% CI = 2.9-3.6) than in women (SIR = 2.0; 95% CI = 1.8-2.2). The incidence of primary liver cancer alone was increased fourfold (SIR = 4.1; 95% CI = 3.8-4.5); again, the risk was higher in men (SIR = 4.7; 95% CI = 4.2-5.2) than in women (SIR = 3.4; 95% CI = 2.9-3.9). Smaller increases in risk were seen for cancers of the gallbladder, the extrahepatic bile ducts, and the ampulla of Vater. After exclusion of diabetic patients with concomitant diseases that predispose to primary liver cancer, such as alcoholism, cirrhosis, and hepatitis, the persistence of an approximately threefold excess risk was observed.

CONCLUSIONS

Our findings suggest that patients with diabetes are at increased risk of developing primary liver cancer and perhaps cancers of the biliary tract. The mechanisms involved in the association of diabetes and liver cancer remain to be clarified. Additional studies are needed to determine whether patients with insulin-dependent diabetes mellitus and those with non-insulin-dependent diabetes mellitus differ in their risk for primary liver cancer or whether the risk is affected by the type of diabetes treatment.

Risk of colorectal cancer and other cancers in patients with gall stones

BACKGROUND

The occurrence of gall stones has repeatedly been associated with an increased risk for cancer of the colon, but risk associated with cholecystectomy remains unclear.

AIMS

To evaluate the hypothesis in a nationwide cohort of more than 40,000 gall stone patients with complete follow up including information of cholecystectomy and obesity.

PATIENTS

In the population based study described here, 42,098 patients with gall stones in 1977-1989 were identified in the Danish Hospital Discharge Register.

METHODS

These patients were linked to the Danish Cancer Registry to assess their risks for colorectal and other cancers during follow up to the end of 1992.

RESULTS

The analysis showed a modest increase in the number of cancers at all sites combined (n = 3940; RR, 1.07; 95% confidence intervals (CI), 1.0 to 1.1). A weak association was found for cancer of the colon (n = 360; RR, 1.09; 95% CI 1.0 to 1.2), which remained unchanged when analysed by sex, anatomical subsite, and duration of follow up. Multivariate analysis with adjustment for cholecystectomy and clinically defined obesity did not change these estimates to any significant extent. Excess risks were found for cancers of the pancreas and the small intestine. A non-significant increased risk for breast cancer was seen in women five years after initial discharge for gall stones.

CONCLUSION

A borderline significant association was seen between gall stones and cancer of the colon, and for cancer of pancreas and small intestine as well as for breast cancer in women.

Underreporting and misclassification of urinary tract cancer cases on death certificates

We compared the diagnoses for decreased cases with urinary tract cancer reported to the Surveillance, Epidemiology, and End Results (SEER) program with their underlying cause of death reported on death certificates. Deaths for a substantial proportion of cases were ascribed to noncancer causes (bladder, 48%; kidney, 28%; renal pelvis, 37%; and other urinary tract, 38%), which decreased with advancing stage at diagnosis and increased with length of survival. In general, cancer deaths were more likely to be recorded to the predominant subsite within an organ. Only 5.5% of renal pelvis cancer patients were recorded to have died of their illness, whereas 33.7% of their deaths were reported as due to kidney cancer. On the other hand, over 85% of urinary tract cancer deaths reported on the death certificates were confirmed by SEER diagnosis, although the extent of agreement varied by stage at diagnosis and age at death for kidney and renal pelvis cancers.

The risk of stomach cancer in patients with gastric or duodenal ulcer disease

BACKGROUND

Helicobacter pylori infection, now considered to be a cause of gastric cancer, is also strongly associated with gastric and duodenal ulcer disease. The discovery of these relations has brought the long-controversial connection between peptic ulcers and gastric cancer into focus.

METHODS

We estimated the risk of stomach cancer in a large cohort of hospitalized patients with gastric or duodenal ulcers, as recorded in the Swedish Inpatient Register between 1965 and 1983. Altogether, 57,936 patients were followed through 1989, for an average of 9.1 years. The standardized incidence ratio--the ratio of the observed number of cancers to the number expected on the basis of the incidence in the Swedish population at large--was used as a measure of relative risk.

RESULTS

After peaking in the first 3 years of follow-up, the standardized incidence ratio for gastric cancer among 29,287 patients with gastric ulcers leveled off at 1.8 (95 percent confidence interval, 1.6 to 2.0) and remained significantly increased throughout follow-up, which was as long as 24 years for some patients. Prepyloric ulcer, diagnosed in 8646 patients, was not associated with a significant excess risk (standardized incidence ratio, 1.2; 95 percent confidence interval, 0.8 to 1.6). In the cohort of patients with duodenal ulcers (24,456 patients), the incidence of gastric cancer was significantly lower than expected. After the second year of follow-up, the standardized incidence ratio was only 0.6 (95 percent confidence interval, 0.4 to 0.7) and remained stable thereafter.

CONCLUSIONS

Gastric ulcer disease and gastric cancer have etiologic factors in common. A likely cause of both is atrophic gastritis induced by H. pylori. By contrast, there appear to be factors associated with duodenal ulcer disease that protect against gastric cancer.

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China

BACKGROUND

The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach.

METHODS

Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers.

CONCLUSIONS

Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China

BACKGROUND

The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach.

METHODS

Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers.

CONCLUSIONS

Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

Anthropometric and reproductive factors and the risk of pancreatic cancer: a case-control study in Shanghai, China

To examine the possible role of body size and reproductive factors in pancreatic cancer, data were analyzed from a population-based case-control study conducted in Shanghai, China. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990, and June 30, 1993. Deceased cases (19%) were excluded from the study. Controls (n = 1,552) were randomly selected from permanent Shanghai residents and frequency-matched to cases by gender and age. Information on body size and reproductive and other possible risk factors was collected through personal interviews. After adjustment for age, income, smoking and other confounders, a positive dose-response relation between body mass index and risk of pancreatic cancer was observed in both sexes. Among women, the risk of pancreatic cancer was significantly associated with number of pregnancies and live births. Compared with 0-2 pregnancies or live births, the odds ratio (OR) for 8 or more pregnancies was 1.90, while that for 5 or more births was 1.88. A modest elevation in risk, independent of parity, was associated with early age at first birth. Risk increased over 40% among women with a first birth at or before age 19 years relative to those at age 26 years or older. Ever use of oral contraceptives was associated with excess risk, though based on small numbers of users. Our findings suggest that, in Shanghai, obesity, gravidity, parity and perhaps use of oral contraceptives are associated with moderate increases in risk of pancreatic cancer, indicating that hormonal determinants deserve further investigation.

Biliary tract cancers among textile and other workers in Shanghai, China

Using occupational data for more than 500 patients with cancers of the biliary tract (CBT) diagnosed between 1980 and 1984 in Shanghai, and employment information from the 1982 census for the Shanghai population, the associations between CBT and occupational categories were examined by standardized incidence ratios (SIR). Compared to the general population, risk was elevated by nearly 40% among textile workers (SIR for women = 137, 95% CI = 106-175 and SIR for men = 137, 95% CI = 76-217), consistent with other investigations linking CBT to textile work. Increased risks were observed also among waiters/ waitresses, male sanitation personnel and chemical workers, and female janitor and similar workers. Although causal inferences cannot be firmly drawn, our findings add to the limited evidence linking CBT to occupational exposures, especially in the textile industry.

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China

BACKGROUND

The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach.

METHODS

Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers.

CONCLUSIONS

Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

Anthropometric and reproductive factors and the risk of pancreatic cancer: a case-control study in Shanghai, China

To examine the possible role of body size and reproductive factors in pancreatic cancer, data were analyzed from a population-based case-control study conducted in Shanghai, China. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990, and June 30, 1993. Deceased cases (19%) were excluded from the study. Controls (n = 1,552) were randomly selected from permanent Shanghai residents and frequency-matched to cases by gender and age. Information on body size and reproductive and other possible risk factors was collected through personal interviews. After adjustment for age, income, smoking and other confounders, a positive dose-response relation between body mass index and risk of pancreatic cancer was observed in both sexes. Among women, the risk of pancreatic cancer was significantly associated with number of pregnancies and live births. Compared with 0-2 pregnancies or live births, the odds ratio (OR) for 8 or more pregnancies was 1.90, while that for 5 or more births was 1.88. A modest elevation in risk, independent of parity, was associated with early age at first birth. Risk increased over 40% among women with a first birth at or before age 19 years relative to those at age 26 years or older. Ever use of oral contraceptives was associated with excess risk, though based on small numbers of users. Our findings suggest that, in Shanghai, obesity, gravidity, parity and perhaps use of oral contraceptives are associated with moderate increases in risk of pancreatic cancer, indicating that hormonal determinants deserve further investigation.

Balloon mitral commissurotomy in a patient with situs inversus and dextrocardia

A patient with situs inversus and dextrocardia in whom a successful balloon mitral commissurotomy for symptomatic rheumatic mitral stenosis was performed after appropriate modifications in the technique of transseptal catheterization is described.

Massive cerebral infarction: a potential fatal complication of plaque fissuring of lipid-rich atheromas of the carotid artery. Case reports

The authors report 2 patients who died of massive cerebral infarction secondary to plaque fissuring of and hemorrhage into their carotid atheromas, resulting in overlying thrombosis and total occlustion of the internal carotid arteries. In both cases, the atheromas caused more than 75% reduction in luminal size of the carotid artery. In addition, they were rich in lipid content, which accounted for more than 40% of the cross-sectional area of the atheromatous plaques. It is postulated that high-grade stenotic carotid atheromatous plaques with a high lipid content are at an increased risk of giving rise to subsequent neurologic complications, including massive cerebral infarction, as exemplified by the present 2 reported cases.