Introduction: Among ovarian pathologies, lymphomas represent 1.5%, and all histologies immunophenotipe B non Hodgkin lymphoma corresponds 0.5%. Clinical case: We present a case in which the patient had no symptoms; incidentally, in a gynecological control, clinical detected adnexal mass, and the patient was submitted to a laparotomy. Pathology Department performed immunohistochemistry test and reported lymphoma. Studies were supplemented to define whether it was a primary or a secondary ovarian lymphoma and to discard immunosuppressive diseases. The patient received chemotherapy R-CHOP protocol (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). The answer was sadisfactoria and controls was planned. Conclusions: In the differential diagnosis of ovarian mass, rapid growth should be suspected in a lymphoproliferative entity, because in early stages the prognosis is better; besides, lymphomas are chemosensitive and the use of monoclonal antibodies has improved survival.