11/99. Atypical carcinoid presenting as mesothelioma. Two patients presented with pleuritic pain and dyspnoe together with pleural thickening on the X-ray of the chest. In both a history of exposure to asbestos existed suggesting mesothelioma. A definite diagnosis could not be made and therefore therapy was symptomatic. autopsy revealed the unexpected diagnosis of atypical carcinoid of the lung. In one case, pleural spread of tumor was seen while in the other an extensive fibrotic pleural reaction existed. To our knowledge these cases represent the first examples of atypical carcinoid causing pseudomesothelioma. ( info) |
| OBJECTIVES: This study tested a new high-resolution computed tomography (HRCT) scoring method for asbestos-induced parenchymal changes in the lung. methods: HRCT scans of 602 asbestos-exposed workers and 49 referents were reviewed by 3 radiologists. Structured forms were filled out for a semiquantitative HRCT fibrosis score based on several specified parenchymal abnormalities scored separately. Observer agreement was studied with the use of the quadratic-weighted kappa (kappaqw). The HRCT fibrosis score (from 0 to V with definitions and index images given retrospectively) was compared with the radiographic classification of the International Labour Office (ILO) for the same patients. Receiver-operating characteristic (ROC) curves were computed to compare the tests for diagnosing asbestosis. RESULTS: Good inter- and intraobserver agreements were achieved (kappaqw = 0.64 and 0.72, respectively) as regards the HRCT fibrosis score. All the specified computed tomography findings explained 86% of the variance in the HRCT fibrosis score. Age and occupational group were significant predictors of fibrosis. The area under the roc curve was significantly greater for the HRCT fibrosis score (0.89) than for the ILO radiographic classification (0.76). The sensitivity (70%) and specificity (91%) of the HRCT fibrosis score (classes I/II-V representing asbestosis) were better than those of the classification published by the International Labour Office (51% and 89%, respectively, score > or = 1/0 representing asbestosis). CONCLUSIONS: The examined HRCT scoring method proved to be a simple, reliable, and reproducible method for classifying lung fibrosis and diagnosing asbestosis also in large populations with occupational disease, and it would be possible to use it as a part of an international classification. ( info) |
13/99. Computed tomography screening for lung cancer in asbestos-exposed workers. We conducted a computed tomography (CT) screening for lung cancer in a high-risk population. Six hundred and two workers (38-81 years, 97% smokers) with asbestos-related occupational disease were screened using spiral CT and chest radiography. The national cancer registry was checked for possible false negative cases. The screening detected 111 patients with non-calcified nodules >0.5 cm in diameter and 66 of them were referred for further hospital examination. We found five lung cancers (106 false positive cases) with a histological spectrum similar to the national, natural occurrence of the disease (two adeno, one squamous cell, one anaplastic and one metastatic carcinoma) and one peritoneal mesothelioma. Three cases were potentially operable (stage I-II). Unfortunately there was one false negative fine-needle aspiration biopsy (FNAB) with misinterpretation of the follow-up CT scan and another patient who refused further investigations after an inadequate FNAB. In the end only one patient with adenocarcinoma underwent surgery. After 3 years of follow-up two new lung cancers were reported to the cancer registry with no evidence of tumour in the retrospective analysis of the screening CT scan. The sensitivity of CT screening was 100%. CT was capable of detecting early lung cancer in asbestos-exposed patients with a lot of confusing pulmonary and pleural pathology. Due to the high number of positive findings attention should be paid to patient compliance and the follow-up protocols and patient selection in future screening programmes. ( info) |
14/99. Fatal asbestosis 50 years after brief high intensity exposure in a vermiculite expansion plant. The authors report the case of a 65-year-old accountant whose only asbestos exposure was during a summer job 50 years earlier in a california vermiculite expansion plant. Vermiculite is a silicate material that is useful in building and agriculture as a filler and insulating agent. He developed extensive fibrocalcific pleural plaques and end-stage pulmonary fibrosis, with rapidly progressive respiratory failure. Careful occupational and environmental history revealed no other source of asbestos exposure, and the initial clinical diagnosis was idiopathic pulmonary fibrosis; open lung biopsy shortly before his death confirmed asbestosis. Electron microscopic lung fiber burden analysis revealed over 8,000,000 asbestos fibers per gram dry lung, 68% of which were tremolite asbestos. Additional asbestiform fibers of composition not matching any of the standard asbestos varieties were also present at over 5,000,000 fibers per gram dry lung. Comparison analysis of a sample of Libby, montana, vermiculite showed a similar mix of asbestiform fibers including tremolite asbestos. This case analysis raises several concerns: risks of vermiculite induced disease among former workers of the more than 200 expansion plants throughout the united states; health effects of brief but very high-intensity exposures to asbestos; and possible health effects in end-users of consumer products containing vermiculite. ( info) |
15/99. Papillary mesothelioma of the peritoneum in the absence of asbestos exposure. BACKGROUND: Malignant mesothelioma of the peritoneum is a very rare neoplasm, commonly associated with asbestos exposure and often rapidly fatal. Well Differentiated Papillary mesothelioma of the peritoneum (WDPMP) is regarded as a less aggressive variety of the tumor. Progressive ascites is often the only clinical manifestation of the disease and differentiation of WDPMP from benign mesothelial hyperplasia or adenocarcinoma is difficult. patients AND methods: Here we report the case of a 45-year-old patient who presented with ascites but without evidence of portal hypertension, liver disease or abdominal malignancy. On diagnostic laparoscopy small tumor nodules were found to cover the parietal peritoneum and the greater omentum and histopathologically corresponded to papillary mesothelial hyperplasia with minimal nuclear atypia. Histochemically biopsies were positive for Calretinin, Cytokeratins and Epithelial Membrane Antigen (EMA). Based on these findings the diagnosis of WDPMP was made and the patient was closely followed without primary cytostatic therapy. CONCLUSIONS: Progressive ascites was the only clinical symptom in this patient, while liver disease, portal hypertension and gastrointestinal malignancies were ruled out by clinical, laboratory and imaging techniques. Laparoscopic biopsy revealed WDPMP to be the underlying disease. Immunocytochemistry is required to establish the diagnosis of this rare malignant disorder which is even more uncommon in the absence of a history of asbestos exposure. Due to the indolent course of WDPMP therapy should only be initiated when signs of rapid tumor progression become apparent. ( info) |
16/99. Environmental sample correlation with clinical and historical data in a friction product exposure. Asbestos has been widely used in the past as a component in friction products. A unique setting of dust exposure to such products occurs when individuals are involved with refabrication of the worn components. It is of interest whether asbestos fibers are released from friction materials in the use phase and the postlife phase or if the mineral fibers are converted to a nonasbestos form. In the present study, an individual whose primary work activity had centered on clutch refabrication was evaluated for possible dust-related diseases. Tissue analysis revealed the presence of large numbers of asbestos fibers as well as ferruginous bodies. These particulates were characterized as to composition as well as dimensions. Clutches of the type typically used by this individual were obtained and material was rinsed from their surface for comparative purposes. Materials that were freed from the surface and reviewed by analytical transmission electron microscopy were clearly identifiable as chrysotile asbestos. The composition of the clutch material was compared with the components found in the patient's lung tissue. The conclusion from this comparison was that individuals exposed to friction materials under similar circumstances should use appropriate caution. Appreciable exposure to asbestos can occur and this exposure can be sufficiently high to result in disease. ( info) |
| By the use of transmission electron microscopy (TEM) and energy dispersion spectrometry the amount (mean value mean = 191 /- 94 fibers/mg of tissue) and the type (chrysotile and tremolite) of asbestos fibers have been determined in tissue samples of four bladder cancer patients affected by pulmonary asbestosis, working in the same plant producing asbestos-cement pipes and boards. Similar measurements were carried out on samples of bladder cancers of eight control patients not professionally exposed to asbestos. Only five of them also revealed chrysotile fibers (mean = 151 /- 196 fibers/mg of tissue). The paucity of the study and control cases and the small quantitative difference between them regarding the presence of infraneoplastic asbestos fibers does not consent us to hypothesize a causal relationship between tumor and occupational exposure. ( info) |
18/99. Asbestos-related pleural thickenings in Japanese sake brewers. Asbestos was long used as an additive material for the filtration of many kinds of alcoholic beverages. There has been, however, only one case report of a distiller in italy showing pleural thickenings and lung parenchymal fibrosis due to exposure to asbestos. We report a retired Japanese sake brewer who showed bilateral calcified pleural plaques on chest X-ray films. x-ray diffraction analysis and energy disperse X-ray microanalysis demonstrated the additive material used for sake filtration to be almost pure chrysotile. Furthermore, 17 cases showing probably asbestos-related pleural thickenings were found on examination of 235 chest X-ray films of male workers at different sake breweries. These findings indicate that Japanese sake brewers should be listed as workers at possible risk of asbestos-related health problems. ( info) |
19/99. Oxalate deposition on asbestos bodies. We report on a deposition of oxalate crystals on ferruginous bodies after occupational exposure to asbestos demonstrated in 3 patients. We investigated the mechanism and possible significance of this deposition by testing the hypothesis that oxalate generated through nonenzymatic oxidation of ascorbate by asbestos-associated iron accounts for the deposition of the crystal on a ferruginous body. Crocidolite asbestos (1000 microg/mL) was incubated with 500 micromol H(2)O(2) and 500 micromol ascorbate for 24 hours at 22 degrees C. The dependence of oxalate generation on iron-catalyzed oxidant production was tested with the both the metal chelator deferoxamine and the radical scavenger dimethylthiourea. Incubation of crocidolite, H(2)O(2), and ascorbate in vitro generated approximately 42 nmol of oxalate in 24 hours. Oxalate generation was diminished significantly by the inclusion of either deferoxamine or dimethylthiourea in the reaction mixture. Incubation of asbestos bodies and uncoated fibers isolated from human lung with 500 micromol H(2)O(2) and 500 micromol ascorbate for 24 hours at 22 degrees C resulted in the generation of numerous oxalate crystals. We conclude that iron-catalyzed production of oxalate from ascorbate can account for the deposition of this crystal on ferruginous bodies. ( info) |
20/99. Peritoneal mesothelioma after environmental asbestos exposure. mesothelioma are primary malignant neoplasms of the serous membranes. They usually involve the pleura and rarely the pericardium, the peritoneum and the tunica vaginalis testis. About 90% are associated with exposure to asbestos. The exposure is generally occupational, an environmental inhalation of asbestos and asbestiform fibers in areas in turkey has been observed and presents a major health problem. This report of a patient from Anatolia with peritoneal mesothelioma after environmental exposure outlines the importance of considering this pathology in the differential diagnosis of a Turkish patient presenting with ascites. ( info) |