[Sino-nasal inverted papillomas and occupational etiology]

The sino-nasal inverted papilloma is a rare benign tumour with certain aggressive features because of frequent relapses and the high probability of malignant degeneration. For these reasons, several studies have been made to evaluate the efficacy of the different courses of treatment, but only afew studies have been carried out to establish the etiology of this tumour, which is still uncertain. Although it is believed that viral infection, chronic inflammation and cigarette smoking can play an important etiological role, it has recently been suggested that occupational risk factors, such as those involved in malignant epithelial sino-nasal cancer (SNC), can also be involved in causing sino-nasal inverted papilloma. A group of 70 patients was examined who have been diagnosed with inverted papilloma from 1991 to 2003; the occupational history, collected via the standardized questionnaire, showed that risk factors like wood and leather dusts, chromium and nickel vapours or fumes and formaldehyde were associated with only 5% of all cases. This proportion is much lower than that established for SNC in several epidemiological studies. Although occupational environmental pollution can be a source of chronic sino-nasal mucosa irritation, on the basis of our results we believe that a causal relationship between exposure to occupational risk factors and inverted papilloma is not likely, differently from the suggestions made in other studies. Consequently, an epidemiological surveillance of inverted papilloma as a "sentinel" tumour, as has been proposed in Italy for SNC, is not considered necessary. Among the possible non-occupational risk factors we observed that 75% of the male patients were smokers and 40% of all patients suffered from chronic sinusitis and sino-nasal polyps. Lastly, among the 70 cases of inverted papilloma, we observed 5 with malignant degeneration.