Clinical Background
Mesothelioma is a rare malignancy involving the serous lining of body cavities (pleura, peritoneum, pericardium or tunica vaginalis testis).
Epidemiology
- Incidence
- 2500-3000 new cases annually in the U.S.
- Occurrence is rising in males greater than or equal to 75 years old; however, it is not in males and females <75 years old (coincides with OSHA restrictions of permissible limits of asbestos exposure)
- Maximum lifetime risk in 1925-1929 birth cohort
- Age - peak age 40-60 years
- Gender - strong male predominance
Risk factors
- Asbestos exposure (amphiboles more carcinogenic than chrysotile fibers)
- 80% of mesothelioma cases occur in patients with history of asbestos exposure
- At-risk occupations include shipbuilding, construction, fireproofing, automobile brakes and clutches, ceiling tiles, boilers (especially in construction prior to 1970)
- Genetics
- Chromosome deletions (1p, 3p, 9p, 6q)
Clinical presentation
- Pleural
- Dyspnea, nonpleuritic chest pain, pleural effusion, cough, fatigue
- Peritoneal
- Abdominal pain, ascites
- Pericardial
- Chest pain, constrictive pericarditis
- Disease process is usually advanced at time of presentation
Pathophysiology
- 3 types of malignant mesothelioma
- Epithelial - 50%
- Sarcomatous - 15%
- Biphasic (or mixed) - 25%
- May be mistaken for adenocarcinoma
- Long latency period (>20 yrs) between asbestos exposure and development of mesothelioma
- Asbestos fibers are mutagenic and carcinogenic to several cells
- Commonly found in excised tumors
See Also
