Abstract
INTRODUCTION: Kaposi sarcoma is an angioproliferative disorder that requires infection with human herpesvirus 8 (HHV-8) for its development. The majority of cases are associated with HIV infection or other immunocompromising conditions. Thymomas are occasionally associated to cytopenia, which may alter the patients' immune responses. METHODS: Case report using clinical records. RESULTS: Case report of a 46-year-old male patient diagnosed with thymoma and myasthenia gravis. The patient was referred to an otolaryngology consultation with complaints of facial pain in the right malar region, interpreted as an acute sinusitis. Following examination, an expansive maxillary sinus mass was found, and endoscopic surgery was undertaken. After careful investigation, it was diagnosed as a Kaposi sarcoma. CONCLUSIONS: It is thought to be the first described case of a maxillary sinus Kaposi sarcoma in an HIV-negative patient. Thus, this entity has to be considered in the differential diagnosis of sinus masses, even in non-HIV patients.