This is a case report of localized aggressive periodontitis associated with unusual gingival enlargement. There was difficulty both clinically and histologically in deciding whether the gingival enlargement was a pyogenic granuloma or a Kaposi sarcoma. The diagnosis of Kaposi sarcoma was eventually ruled out by the failure of immunohistopathological examination to demonstrate the presence of HHV-8 DNA markers, and by the clinical response of the lesions to antimicrobial agents. Once a definitive diagnosis was made, the patient was treated conventionally.