Abstract
BACKGROUND: Malignant mesothelioma is a rare, aggressive neoplasm arising from mesothelial cells of the pleura, peritoneum, pericardium, or tunica vaginalis. The primary risk factor is asbestos exposure, particularly occupational. Given its long latency period, the persistence of asbestos sources despite legislation, and recognition of other risk factors, new cases are expected to emerge annually. This study retrospectively analyses the incidence and characteristics of mesothelioma cases diagnosed over 36 years in a hospital in northern Portugal, along with a sociodemographic description of this population. METHODS: Patients diagnosed with mesothelioma (International Classification of Diseases for Oncology morphological code M-905x/3) were identified through the National Oncological Registry. Collected data included sex, age at diagnosis, year of diagnosis, tumor location, and histological subtype. Medical records were reviewed for relevant personal and occupational histories. RESULTS: A total of 82 patients were diagnosed with mesothelioma between 1988 and 2023: 11 cases up to 1999, 29 from 2000 to 2011, and 42 from 2012 to 2023. Of them, 69.51% (n = 57) were male, with a mean age at diagnosis of 67 ± 13 years [range: 28-85]. Diagnoses occurred in 12.20% (n = 10) younger than 50 years, 35.37% (n = 29) between 50-69, and 52.44% (n = 43) older than 70 years. Pleural involvement was observed in 86.59% (n = 71) and peritoneal in 13.41% (n = 11). Histological subtypes included epithelioid (34.15%; n = 28), biphasic (19.51%; n = 16), sarcomatoid (14.63%; n = 12), and unknown (31.71%; n = 26). Occupational history was identifiable in 40.24% (n = 33); 20 had probable asbestos exposure. Two cases were linked to nonoccupational causes. CONCLUSIONS: Despite asbestos bans, mesothelioma remains a public health concern due to its latency and persistent exposure sources. Cases in younger individuals or women highlight the need to investigate environmental contamination or alternative etiologies. Broader, prospective studies are needed to better understand the disease's evolution and determinants.