OBJECTIVE: To highlight the signs and symptoms of tonsillar lymphoma that usually presents insidiously. CASE REPORT: JFMS, a 57-year-old patient from Manaus, Amazonas, presented with swelling and pain in the left palatine tonsil for the past 2 months; the swelling had been biopsied earlier with a histopathological diagnosis of tonsillar granuloma lacking any features of malignancy. Tonsillar asymmetry was present; the left tonsil was larger than its counterpart and had a white lesion on it. CT scanning of the head and neck showed lymph node infarction on the left side without an increase in soft tissue in the peritonsillar site. Laboratory tests for granulomatous diseases and swabs for fungi yielded negative results. A second biopsy obtained for histopathological and immunohistochemical examination revealed atypical lymphoid hyperplasia with areas of superficial erosion; the final diagnosis was diffuse large B-cell lymphoma, stage II1. The patient underwent tonsillectomy after 6 months of combination chemotherapy; follow up till present date has not shown any recurrence and after 6 months was submitted at tonsillectomy staying in monitoring until now. CONCLUSION: The head and neck region is the second-most common site after the gastrointestinal tract to be affected by extranodal lymphomas. Approximately half of head and neck lymphomas involve the Waldeyer's ring; almost all of these are non-Hodgkin's lymphomas, and the commonest histological type is the diffuse large cell lymphoma. The stage of the disease influences treatment choice between stand-alone radiotherapy or radiotherapy with combination chemotherapy. Early diagnosis of lesions improves the prognosis by allowing the prompt institution of appropriate treatment.