Abstract: Objective To analyze the clinical characteristics of mantle cell lymphoma(MCL)of the Waldeyer's ring. Methods A retrospective study of 4 patients with MCL in the Waldeyer's ring, treated in the department of otolaryngology, head and neck surgery of Peking University First Hospital between 2016 and 2019 were used in this review. Their clinical manifestations, histopathology, immunohistochemistry, cytogenetics, the treatment used, and prognosis were summarized and analyzed in combination with a literature review. Results MCL involving the Waldeyer's ring is extremely rare. The palatine tonsil is the most frequently involved site, followed by the nasopharynx and tongue base. They generally present with asymptomatic soft tissue swelling and typically lack the systemic B symptoms. When the tumor is large, there are corresponding obstruction symptoms. For MCL in the nasopharynx, the symptoms are a unilateral or bilateral nasal obstruction with or without ear fullness. For MCL in the palatine tonsil or tongue base, the most common symptoms were a sensation of fullness of the throat, difficulty swallowing, and not having clear speech because of the tumor in the oral cavity. Examination revealed soft tissue swelling of the nasopharynx, palatine tonsil or tongue base. MCL was diagnosed by examining the affected tissue obtained from a biopsy of the lymph node, tissue, bone marrow, or blood phenotype. MCLs have distinct immunophenotype expressing pan B-cell markers(CD 19, 20, and 22). Generally, the T-cell marker CD5 is also expressed, giving this tumor a characteristic profile. The most sensitive and specific marker for MCL is CyclinD1, of which almost all cases are moderately to strongly positive. MCL is characterized by a genetic profile of t(11;14)(q13;q32)in nearly all cases that can be evaluated by conventional cytogenetics and fluorescencein situ hybridization. MCL patients frequently present at an advanced disease stage with extranodal involvement, resulting in poor clinical outcomes due to frequent relapse and the aggressive course. Treatment options for MCL vary widely, with poor prognosis. Conclusions MCL may rarely occur in the Waldeyer's ring. It may be diagnostically challenging to differentiate from other lymphomas that may occur in this area. However, it exhibits some distinctive histological and immunohistochemistry traits which can help distinguish it. Due to the poor overall prognosis, early identification would be important in providing individualized treatment. Rituximab combined with chemotherapy and the use of new drugs such as ibrutinib can improve the prognosis of patients.

Key words: Waldeyer's ring, Mantle cell lymphoma, Non-Hodgkin's lymphoma