[Clinicopathologic characteristics and prognositic indicators of tonsillar mantle cell lymphoma]

Objective: To investigate clinicopathological features and prognosis of tonsillar mantle cell lymphoma(TMCL). Methods: Clinical data of 25 patients with TMCL at Beijing Friendship Hospital, Capital Medical University from 2002 to 2016 were included. All the cases were reviewed microscopically. Various immunohistochemical stains were performed using the MaxVision two-step method. IgH/CCND1 gene fusion was detected by fluorescent in situ hybridization(FISH). Additionally, randomly selected 40 cases of non-tonsil MCL of the same period were compared. Results: Among all mantle cell lymphomas (MCL), TMCL accounted for 5.6%(25/449). The median age of the patients was 60 years(range: 44-82 years) with a M∶F ratio of 5.3 to 1.0. The main symptoms were sore throat and foreign body sensation and patients usually presented with enlargement or mass of tonsil. At the early stage of the disease, 18 cases(72.0%) were clinically misdiagnosed as tonsillitis. Lymph node involvement was present in 76.0%(19/25) of the patients. There were 4 cases(16.0%)with current splenic involvement, 11 cases(44.0%) with pharyngeal focal recidivism, and 3 cases(12.0%) with involvement of other non-lymphoid organs. Morphologically, tonsillar architectures were effaced at various degrees. Eighteen MCL cases showed classical type and 7 cases were blastoid variant. All tumors were positive for CD20 and cyclin D1. 92.0%(23/25) tumors showed weakly positive or positive expression for CD5. FISH test that IgH/CCND1 gene fusion was positive in two CD5 negative classical cases. 18 patients(72.0%) had a median follow-up time of 26 months(range: 6-81 months). The difference of survival rate between stage Ⅰ-Ⅱ and stage Ⅲ-Ⅳ patients was not statistically significant(P>0.05). Compared with NTMCL, TMCL was found to have higher proportion of stage Ⅰ-Ⅱ disease (χ(2)=12.789, P<0.01), lower the proportion of non-lymphatic organ involvement (χ(2)=8.125, P<0.01), and better prognosis (χ(2)=4.351, P=0.037). Conclusion: The incidence of TMCL is low and prone to be misdiagnosed as tonsillitis. Patients with TMCL are more likely at stage Ⅰ-Ⅱ at presentation and the prognosis is better than that of NTMCL.