Asbestos and onset of mesothelioma: case report

Abstract

L'asbesto (o amianto) è un minerale appartenente al gruppo dei silicati fibrosi. Fino al 1991,per le caratteristiche dell’amianto,cioè la notevole resistenza alle elevate temperature, la sua conformazione in fibre e il costo molto basso è stato utilizzato per produrre materiali in grado di resistere alle alte temperature. I silicati di amianto a matrice solida avevano trovato largo uso in edilizia, nell’ impiantistica resistente al calore, nelle tubature per acquedotti e fognature, nei pannelli e fogli per controsoffittature, negli intonaci e come materiale fonoassorbente. Anche nell’industria manifatturiera è stato largamente impiegato per la produzione di manufatti ed oggetti di uso domestico, come isolante termico per alte e le basse temperature,condotte antifiamma, per la produzione di elettrodomestici con utilizzo di alte temperature (stufe, phon, etc.), nei freni nelle frizioni, negli schermi parafiamma nelle guarnizioni, nella produzione di tessuti per indumenti in grado di proteggere dal calore (guanti, tute ignifughe) e di tessuti da arredo resistenti a temperature elevate. L’esposizione ad atmosfere contenenti amianto può essere causa di numerose patologie come l’asbestosi polmonare, i mesoteliomi e il carcinoma polmonare. Le forme più nocive di amianto sono gli anfiboli, fra questi la crocidolite è quella con maggior potenziale neoplastico. Tuttavia, la diagnosi di malattia professionale correlata ad amianto non è semplice né automatica, occorre rispettare una serie di criteri, verificando markers immunoistochimici, monitoraggi biologici ed ambientali, anche personali, per accertare una correlazione effettiva. Inoltre, le conoscenze riguardo alle patologie asbesto-correlate ed i criteri diagnostici si sono evoluti nel tempo, e considerando il periodo di latenza delle malattie, in particolare delle neoplasie, è difficile verificare l’esposizione pregressa dei pazienti che hanno manifestato clinicamente la malattia solo in tempi recenti, magari 10-20 anni dopo l’ultima supposta esposizione. Riportiamo due case report di mesotelioma maligno, di supposta origine professionale amianto-correlata, discutendone l’eziologia alla luce di un Asbestos and onset of mesothelioma: Case Report www.preventionandresearch.com 136 Apr-Jun 2013|P&R Scientific|Volume 3|N°2 excursus della letteratura. Per censire, analizzandola, tutta la conoscenza scientifica circa la relazione tra salute umana e asbesto, prodotta dall’inizio della storia dell’utilizzo industriale ad oggi, abbiamo consultato la letteratura in rete tramite motori di ricerca con utilizzazione di parole chiave. Sono state interrogate con questo sistema le principali banche di dati scientifici mondiali (Pubmed, Cochrane, Embase, Tripdatabase), sono state censite un totale di 13551 pubblicazioni per ricostruire come e quando sono state pubblicate informazioni sui danni attribuibili ad asbesto. Gli argomenti fondamentali censiti sono stati: “Amianto e danni alla salute”, “Amianto e Mesotelioma Maligno”. In base ai risultati appresi tramite la nostra ricerca, una volta applicati ai due casi in esame, abbiamo appurato che non vi è certezza della diagnosi di mesotelioma maligno attribuito ai due pazienti, in quanto non sono stati applicati rigorosamente i criteri diagnostici suggeriti dalla letteratura internazionale sia sul piano clinico che su quello istopatologico ed immuno-chimico. Background Asbestos is a mineral belonging to the group of fibrous silicates. Asbestos fibers can be found free or weakly bound to each other (friable asbestos) or strongly bound to each other in the case of asbestos in compact matrix. Due to its remarkable resistance to high temperatures, its conformation in fibers and its very low cost, it was used until in Italy 1991 to produce materials able of withstanding high temperatures. The silicates of asbestos in the solid matrix were widely used in construction, in resistant to heat plant engineering, in plumbing for aqueducts and sewers, in panels and sheets for ceilings, in plaster and as sound-absorbing material. It was also widely used in the manufacturing industry for its sound-absorbing characteristics and for the production of manufactured articles and household equipment, such as thermal insulation for high and low temperatures, flame retardant ducts, for the production of appliances with use of high temperatures (stoves, hair dryer, etc.), in the clutches brakes, in the baffle plate display screens in the seals, in the production of clothing protecting from heat (gloves, fireproof suits) and in furnishing resistant to elevated temperatures. The exposure to atmospheres containing asbestos can be the cause of several diseases such as pulmonary asbestosis, mesothelioma and lung cancer. The amphiboles are the most dangerous forms of asbestos and the crocidolite is the one with the most neoplastic potential. The inhalation of even a single asbestos fiber may induce the onset of malignant mesothelioma or other forms of lung cancer. Differently from other substances and dangerous preparations, there is no risk threshold below which the concentration of asbestos fibers in inspired air may be considered safe. Obviously prolonged exposure to asbestos fibers, or inhalation of large amounts, increases exponentially the chances of developing asbestos-related malignancies. Before the eighties, the risk of exposure to asbestos was only considered work-related, but today asbestos is considered as an environmental pollutant. In 1992 legislative decree 257 banned in Italy the use and the processing of asbestos and it gave the standards for decontamination of the areas affected by asbestos pollution. Case report We report here two cases of pleural mesothelioma. Case 1: Male, born in 1956, worked for 18 years on several ships as non-commissioned officier. In 2004 he underwent surgery for right pneumonectomy with partial pericardial and right hemidiaphragm resection and subsequent reconstruction through Goretex implants, followed by successive cycles of radiotherapy. In 2005 the patient presented with "anorexia, worsening dyspnea, and was operated again for mesothelioma, with laterocervical lymphadenopathy." The histopathological examination of biopsy material from laterocervical lymph node was so reported: "localization of malignancy with morphological features consistent with mesothelioma". Subsequently a right pleural effusion was found. After thoracentesis and cytologic evaluation of pleural fluid a pleural mesothelioma was once again confirmed. The definitive histological examination gives evidence of biphasic malignant mesothelioma infiltrating the lung, with lymph node micro metastasis pT3N1MX . Asbestos and onset of mesothelioma: Case Report www.preventionandresearch.com 137 Apr-Jun 2013|P&R Scientific|Volume 3|N°2 The patient's condition worsened, with the appearance of severe dyspnea and congestive cardio-circulatory followed by death on September 2005. From the autopsy: "The right parietal pleura is in part thickened and in part replaced by implants. Absence of the right lung. On the left lung the presence of tenacious adhesions is found. The left pleura appears thickened because of the presence of a neoformation of lipidic consistency, that presents in section large necrotic areas; the above lesion expatiates infiltrating diffusely chest wall, left lung, pericardium, diaphragm, up to the falciform ligament and retroperitoneum and incorporating the mediastinal organs (esophagus and trachea). Multiple samples of the lipidic neoformation have been withdrawn in the pleura, the pericardium and the left lung”. From the medical report of the histopathological examination of pleuro-pulmonary biopsy material taken during autopsy: “Fairly cellular neoformation interesting massively visceral and parietal pleura with invasion by contiguity of the soft tissues of the chest wall and the lung parenchyma and interesting diffusely pericardium with infiltration by contiguity of the subepicardial myocardium and aspects of vascular invasion. The neoformation is mainly composed of atypical elements variously twisted and arranged in corrugated, swirling structures, and included in a fibrous stroma. We proceeded to set up preparations of neoplastic tissue treated with immunochemical techniques, in order to highlight the possible mesothelial origin of the tumor". The following results have been achieved (Tab. 1): Table 1 Results of Case 1 neoplastic markers