Morphology of Liver Damage Among Polyvinyl Chloride Production Workers. A Report on 51 Cases

Abstract

After previous reports on alterations of the liver among polyvinyl chloride production workers," ' we now have a survey of 51 patients who were exposed to vinyl chloride for different long periods and were controlled clinically and by biopsies in different intervals after the last exposure.In contrast to the impressive macroscopical and endoscopical findings, the histological alterations of the liver were, in most cases, rather discrete and unspecific. With the material at our disposal (51 cases) we were able to classify the histological findings into 5 groups (TABLE 1).First, there were degenerative changes of the liver parenchyma such as a hydropic degeneration of hepatocytes in increasing severity, e.g. , a toxic swelling of hepatocytes with granulary cytoplasm (cloudy swelling) progressing to vacuolar degeneration, occasionally even to a ballooning of the cells (FIGURE 1). Further, we found focal cytoplasmic degeneration sometimes mimicking Mallory bodies. Eosinophilic single cell necroses appeared in advanced cases (FIGURES 1 and 3a). These toxic lesions of the cytoplasm were localized in sharply delimited areas of the lobules (FIGURE 1). The pressure exerted by the areas of toxically swollen hepatocytes seems to cause some kind of pressure atrophy on the surrounding parenchyma.In about half of the cases we observed a slight to moderate disseminated fatty degeneration of medium to large sized fat vacuoles. The distribution pattern and the size of the fat vacuoles corresponded to the type of fatty change produced by different toxic injuries, alcohol being included. In no cases have TABLE 1 LIVER DAMAGE AFTER EXPOSURE TO VINYL CHLORIDE

Liver Angiosarcoma and Hemangiopericytoma after Occupational Exposure to Vinyl Chloride Monomer

“…The histologic finding of ASL in our patient ( Figure 1) shows large vascular spaces lined with atypical vascular epithelium and with polymorphism and hyperchromatism of cells. This is in complete agreement with the description of ASL in the literature (11,12). This patient's medical history is characteristic for at least two reasons: a) there was a relatively brief period of occupational exposure to VCM, and b) the tumor developed 15 years after the 4-year occupational exposure to high VCM concentrations, although after the exposure, the patient was transferred to a job where no VCM emissions occurred (transport worker).…”

“…Angiosarcoma is a rare tumor with an incidence of 1:7,000,000 inhabitants; a clear excess of cases in vinyl chloride workers reported by Lee Popper and colleagues (10-11) and Gedigt et al (12) (17)(18)(19)(20). The histologic finding of ASL in our patient ( Figure 1) shows large vascular spaces lined with atypical vascular epithelium and with polymorphism and hyperchromatism of cells.…”

Toxicant-associated Steatohepatitis

“…However, as early as 1975, it was recognized that “fatty changes” similar to those observed in ALD were present in about half of biopsied chemical workers with high cumulative exposures (Gedigk, Muller, and Bechtelsheimer 1975). In fact, in his final article addressing FHH and FMH, Hans Popper noted that these lesions were often obscured by “fatty infiltration and/or chronic disease (hepatitis/granuloma)” (Tamburro, Makk, and Popper 1984).…”

Liver angiosarcoma and hemangiopericytoma after occupational exposure to vinyl chloride monomer.

“…Gedigt et al (12) have undoubtedly provided the greatest contribution in the study of the histogenesis and pathohistology of ASL. The onset of angiosarcoma usually includes proliferation of sinusoidal cells and sinusoidal dilatation leading to atypical hyperplasia, whereas direct stimulation of hepatocytes with VCM leads to proliferation of hepatocytes, formation of regeneratory nodules, and development of hepatoma (12.…”