Occupational cholangiocarcinoma diagnosed 18 years after the end of exposure to 1,2-dichloropropane and dichloromethane at a printing company: a case report

Early detection of occupational cholangiocarcinoma in a high-risk patient under intensive surveillance: a case study

BACKGROUND

Occupational cholangiocarcinoma is associated with exposure to organic solvents, such as dichloromethane (DCM) and 1,2-dichloropropane (DCP). This report describes a case of occupational cholangiocarcinoma detected through regularly imaging following the discovery of elevated serum γ-glutamyl trans peptidase (γ-GTP) levels revealed during regular checkup.

CASE PRESENTATION

A 43-year-old man who had been working in a printing company with 15 years of exposure to organic solvents presented to our hospital owing to abnormalities found during a routine checkup. Ultrasound (US) imaging revealed thickening of the gallbladder wall accompanied by gallstones, although in the blood tests, γ-GTP levels were within normal range. Given the high risk of cholangiocarcinoma development, the patient underwent regular monitoring with abdominal US and blood tests at a local doctor's office. At the age of 48, his serum γ-GTP level mildly elevated for the first time, prompting the initiation of semi-annual magnetic resonance cholangiopancreatography (MRCP). By the age of 50 years, dilation in B8 was detected, and one and a half years later, a tumor on the central side of the B8 dilation appeared. The patient was diagnosed with intrahepatic cholangiocarcinoma, which was treated with anterior sectionectomy. Pathological examination revealed an adenocarcinoma with a papillary glandular ductal structure at the root of the B8. In addition, biliary intraepithelial neoplasia (BilIN) and dysplasia have been identified around the tumor and periphery bile ducts and in noncancerous bile ducts. Postoperatively, the patient received 6 months of adjuvant chemotherapy with S-1monotherapy. Eight months after surgery, the patient remained under observation with no signs of recurrence.

CONCLUSIONS

We report a case of occupational cholangiocarcinoma detected during a prolonged period of regular follow-up after exposure to DCM and DCP. Given the delayed carcinogenesis process, occupational cholangiocarcinomas manifest long after exposure to organic solvents, therefore, ongoing screening is extremely important. Vigilance is essential to avoid underdiagnosis, particularly for individuals who are at an increased risk of developing this form of cancer. Continuous monitoring is key to the early detection and effective management of occupational cholangiocarcinoma.

Role of Nrf2 in 1,2-dichloropropane-induced cell proliferation and DNA damage in the mouse liver

1,2-Dichloropropane (1,2-DCP) is recognized as the causative chemical of occupational cholangiocarcinoma in printing workers in Japan. However, the cellular and molecular mechanisms of 1,2-DCP-induced carcinogenesis remains elusive. The present study investigated cellular proliferation, DNA damage, apoptosis, and expression of antioxidant and proinflammatory genes in the liver of mice exposed daily to 1,2-DCP for 5 weeks, and the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in these responses. Wild-type and Nrf2-knockout (Nrf2-/-) mice were administered 1,2-DCP by gastric gavage, and then the livers were collected for analysis. Immunohistochemistry for BrdU or Ki67 and TUNEL assay revealed that exposure to 1,2-DCP dose-dependently increased proliferative cholangiocytes, whereas decreased apoptotic cholangiocytes in wild-type mice but not in Nrf2-/- mice. Western blot and quantitative real-time PCR showed that exposure to 1,2-DCP increased the levels of DNA double-strand break marker γ-H2AX and mRNA expression levels of NQO1, xCT, GSTM1, and G6PD in the livers of wild-type mice in a dose-dependent manner, but no such changes were noted in Nrf2-/- mice. 1,2-DCP increased glutathione levels in the liver of both the wild-type and Nrf2-/- mice, suggesting that an Nrf2-independent mechanism contributes to 1,2-DCP-induced increase in glutathione level. In conclusion, the study demonstrated that exposure to 1,2-DCP induced proliferation but reduced apoptosis in cholangiocytes, and induced double-strand DNA breaks and upregulation of antioxidant genes in the liver in an Nrf2-dependent manner. The study suggests a role of Nrf2 in 1,2-DCP-induced cell proliferation, antiapoptotic effect, and DNA damage, which are recognized as key characteristics of carcinogens.

Development of intraductal papillary neoplasm of the bile duct in patients with occupational cholangiocarcinoma

This study aimed to investigate the clinicopathological findings of intraductal papillary neoplasm of the bile duct (IPNB) in patients with occupational cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane to elucidate the development of IPNB to cholangiocarcinoma. The clinicopathological findings of 17 IPNB lesions according to the size (1.5-20 mm in diameter) and their comparison between type 1 (n = 9) and type 2 IPNBs (n = 8) were investigated. An IPNB of <5 mm in size was classified as micro IPNB (n = 7), while those ≥5 mm in size were classified as ordinary IPNB (n = 10). Both types 1 and 2 IPNBs were observed in micro IPNB, and their proportions were not different between micro and ordinary IPNBs. The clinicopathological characteristics of types 1 and 2 IPNBs were fundamentally similar to those previously reported. IPNB with invasive carcinoma was only found in ordinary IPNB although the proportions of low-grade and high-grade epithelium were not different between micro IPNB and ordinary IPNB. All IPNB exhibited γH2AX and S100P, indicating the occurrence of DNA injury and malignant transformation in micro and ordinary IPNBs. These results indicate that the carcinogens may induce micro IPNB with types 1 or 2 at the initiation and then develop ordinary IPNB with types 1 or 2, subsequently, progressing to IPNB with invasive carcinoma in patients with occupational cholangiocarcinoma.

The Proportion of Occupationally Related Cholangiocarcinoma: A Tertiary Hospital Study in Northeastern Thailand

Simple Summary

Northeastern Thailand has the world’s highest incidence rate of cholangiocarcinoma (CCA), whereas a consequence, approximately 14,000 patients die annually. In most cases, the causal factors are identified, but, for some, they remain unknown. Legally imported industrial chemicals such as 1,2-dichloropropane (1,2-DCP), dichloromethane (DCM), and asbestos fibers are defined as occupational causes of CCA. An investigation into these vis-à-vis the diagnosis of occupationally related CCA in Thailand has not been conducted, but is important for understanding the potential magnitude of the problem. The current study found that the proportion of occupationally related CCA was approximately 5.5%, as well as a lower proportion of occupational history taken by treating physicians. Improving physician skills and developing an assistive tool for exploring occupational history might improve the documentation of work-related conditions.

Abstract

Northeastern Thailand registers the highest worldwide incidence of cholangiocarcinoma (CCA). Most of the cases are associated with liver flukes, while unknown causes comprise approximately 10–30% of cases, and these could be due to occupational exposures. Our aim was to determine the magnitude of occupational causes of CCA in a tertiary hospital in northeastern Thailand. We conducted a cross-sectional study with a sample of 220 patients between March and November 2021. Descriptive statistics were used to analyze the findings. Clinical information and telephone interviews were used to explore significant occupational histories. An occupational consensus meeting was held with two occupational physicians, an industrial hygienist, and a hepatobiliary surgeon to decide on the final diagnosis. The response rate was 90.9% (200/220). Based on the medical records and telephone interviews, researchers found that 11 participants had significant exposure. After occupational consensus, it was agreed that the eleven had possible occupational causes, 5.5% (11/200)–54.5% (6/11) being due to asbestos fibers, 45.5% (5/11) due to dichloromethane, and 9.1% (1/11) due to 1,2-dichloropropane. Only 4% (8/200) had occupational histories collected by their treating physicians. Taken together, occupationally related CCA appears to have been underestimated, so improving occupational history taking is needed to properly identify and classify work-related CCA—both for patient treatment and occupational hazard prevention.

Multiple cholangiocarcinomas in the intrahepatic and extrahepatic biliary tree due to dichloromethane exposure: a case report

Background

An outbreak of cholangiocarcinoma in Japan has led to widespread concern among workers in printing plants. In March 2013, the Japanese Ministry of Health, Labour and Welfare, confirmed a causal relationship between cholangiocarcinoma and long-term exposure to dichloromethane (DCM) and 1,2-dichloropropane (DCP), which were widely used in printing plants. We herein report a rare case of successful radical resection of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts caused by past exposure to DCM.

Case presentation

A 54-year-old man developed brown urine 22 years after his last exposure to DCP and DCM. He had an 11-year history of working at a printing plant from the age of 21 to 31 years and dealt with organic solvents during his employment. Enhanced computed tomography revealed a thickened distal bile duct wall with upstream biliary dilatation and multiple intrahepatic cholangiocarcinomas located in liver segments III, VI, and VIII. Biopsy of the distal bile duct wall revealed adenocarcinoma, and a diagnosis of distal cholangiocarcinoma was made. Tumor marker levels were within the reference range (carcinoembryonic antigen, 3.3 ng/mL; carbohydrate antigen 19-9, 25.4 U/mL; SPAN-1, 13 U/mL; and DUPAN-2, 33 U/mL). The multiple intrahepatic and extrahepatic bile duct cancers were treated by subtotal stomach-preserving pancreatoduodenectomy and partial hepatectomy of segments III, VI, and VIII. Pathological examination of the surgical specimens revealed multiple cholangiocarcinomas with well-differentiated adenocarcinoma in the biliary tree. The patient was still alive without recurrence 17 months after the operation.

Conclusions

We experienced a rare case of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts that developed 22 years after the patient’s last exposure to DCP and DCM. Long-term and careful follow-up is required for workers with an occupational history of exposure to organic solvents because of the risk of development of cholangiocarcinoma.