RESUMEN
OBJECTIVES: The aim of this review is to focus on the possibility of patients with squamous cell carcinoma to develop a second primary disease such as DLBCL, perhaps because of the irradiation of the head and neck area. MATERIALS AND METHODS: A case of an 89-year-old man is reported, who initially underwent surgical and complementary treatment for neck squamous cell carcinoma of occult primary and later for tonsillar diffuse large B-cell non-Hodgkin lymphoma. RESULTS: The second primary was considered a recurrence in the neck of the original cancer of unknown primary, so a new surgical management was decided. The final pathology report described a diffuse large B-cell non-Hodgkin lymphoma. CONCLUSIONS: The importance of maintaining follow-ups for patients with occult primary cancers who are at an elevated risk of developing a metastasis or a second primary carcinoma outbreak is highlighted.