Abstract
Introduction: Cystic fibrosis (CF)—is the most common fatal autosomal recessive disease in Caucasians. A number of reports have described patients who do not meet diagnostic criteria for cystic fibrosis. Atypical or nonclassic CF is characterised by normal or borderline sweat test, pancreatic sufficiency and a monosymptomatic phenotype. For these reasons clinicians should remain alert to the possibility of the occurrence of CF. Case report: We described a case presentation of massive nasal polyposis and recurrent sinusitis leading to the diagnosis of cystic fibrosis in a 11-year-old male. Conclusion: Our study indicates that chronic sinusitis and/or polyposis should raise the clinicians suspicion of a potential presentation of undiagnosed CF and require further investigations.