Objective　To　explore　the　clinicopathological　characteristics　of　primary　bladder　mucosal-associated　lymphoid　tissue　extranodal　marginal　zone　lymphoma　(MALToma).　Methods　A　retrospective　case　series　study　was　conducted.　The　clinicopathological　data　of　9　primary　bladder　MALToma　patients　diagnosed　and　underwent　transurethral　resection　of　bladder　tumors　at　the　Fujian　Provincial　Hospital,　Zhangzhou　Municipal　Hospital,　Mindong　Hospital　of　Ningde　City,　Zhangzhou　Second　Hospital　and　Fuzhou　Taijiang　Hospital　from　December　2008　to　December　2021　were　collected.　Paraffin-embedded　surgical　specimens　were　collected　for　HE　staining,　immunohistochemical　staining　and　genetic　testing,　the　clinicopathological　characteristics　of　patients　were　summarized,　and　the　literature　was　reviewed.　Results　Of　the　9　cases,　8　were　female　and　1　was　male,　the　age　was　(59±　11)　years　old　(range:　39-74　years　old).　Two　cases　had　3　lesions,　3　cases　had　2　lesions,　and　4　cases　had　single　lesion.　The　maximum　diameter　of　the　mass　was　(3.2±1.9)　cm　(range:　0.3-7.0　cm).　The　follow-up　time　was　6-127　months,　4　cases　lost　to　follow-up,　4　cases　were　disease-free　survival,　and　1　case　was　survival　with　tumor.　Pathomorphologically,　the　bladder　tissue　consisted　of　diffusely　infiltrating　small-to-medium　sized　lymphocytes,　with　moderate　amounts　of　pale-staining　cytoplasm,　without　obvious　nucleoli,　some　of　them　were　translucent,　and　the　mitosis　was　rare.　Large　cell　proliferation　in　some　areas　was　observed　in　1　case,　with　prominent　nucleoli　and　mitotic　figures.　Tumor　cells　in　all　9　patients　expressed　CD20;　bcl-2,　CD43　and　CD38　were　positive　in　some　cells　in　4　cases,　and　CD138　was　positive　in　a　few　cells　in　2　cases;　κ　was　positive　in　4　cases,　and　scattered　positive　in　5　cases;　λ　was　positive　in　4　cases,　and　scattered　positive　in　5　cases.　B-cell　receptor　gene　clonal　rearrangement　was　positive　in　all　8　cases　who　underwent　the　assay.　No　break-apart　signal　was　observed　in　all　6　cases　who　underwent　the　fluorescence　in　situ　hybridization　assay　with　MALT1　gene　segregation　probe.　Conclusions　Primary　bladder　MALToma　is　a　rare　low-grade　B-cell　lymphoma　that　is　more　commonly　found　in　elderly　women.　There　is　no　abnormal　change　in　MALT1　gene.　©　2024　Chinese　Medical　Journals　Publishing　House　Co.Ltd.　All　rights　reserved.