Purpose: The aim of this literature review and case report was to point out the relationship between Cowden Syndrome (CS) and severe periodontitis. CS is a rare autosomal dominant disorder characterised by skin and oral hamartomas, and is associated with an increased risk of cancer development. Case Report: The case of a 43-year old male patient affected by Cowden syndrome and presenting severe periodontitis was reported. Results: It can be suggested that the specific gingival morphology of the patient with CS might be a risk factor for the development of periodontal disease, as described in the present case report. Conclusion: Early diagnosis is crucial in patients affected by CS. The dentist may be the first to notice any atypical changes in the oral cavity and refer the patient for further examinations. Moreover, the mucosal and skin changes have a tendency to appear prior to the malignancies associated with the syndrome. This highlights the responsibility of the dentist in the early diagnosis of this progressive pathological syndrome. Schlagwörter: Cowden syndrome, multiple hamartoma syndrome, severe periodontal disease, severe periodontitis