Primary tuberculosis of the cavum is a rare entity. It can occur at any age, especially between the second and ninth decade. We report the case of a 17-years-old patient with nasal obstruction and left laterocervical adenomegaly. A cervico-facial CT scan showed a suspicious looking tumor process of the nasopharynx. Histological analysis of the biopsies taken showed chronic granulomatous inflammation with necrosis and the absence of tuberculosis lesions in the usual sites, especially the lungs, led to the diagnosis of primary tuberculosis of the cavum. There was a good evolution on antituberculosis drugs. This unusual location can be a source of difficulties and delay in diagnosis, especially because of the clinical presentation, which suggests a nasopharyngeal tumour. In developing countries, where this disease remains relatively endemic, cross-sectional imaging techniques and histopathological analysis are of great interest for the management of patients.