MALT Lymphoma of the Urinary Bladder Shows a Dramatic Female Predominance, Uneven Geographic Distribution, and Possible Infectious Etiology.

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) of the urinary bladder is an extremely rare entity accounting for 0.2% of all malignant urinary bladder neoplasms, and the diagnosis could be challenging. We present here a patient with urinary bladder MALT lymphoma and review of all published case reports in the literature. We summarized the reported immunophenotype of the neoplasm, ancillary studies, therapy, and follow-up for all 59 patients in the table. The median patients' age was 57 years-old (range, 17 to 88), with female predominance in 50 of 59 patients representing a 1:5.6 ratio. Geographical distribution of the reported patients was as follows: 22 from Asia, of which more than a half (16) originated from Japan; 28 from Europe, of which 19 reported from the United Kingdom, and 3 patients were reported from the United States (including our patient). Twenty-three (77%) of 30 patients, for whom their clinical presentation was recorded, had symptoms of cystitis; Escherichia coli was the most common pathogen. We concluded that a prominent female predominance, uneven geographic distribution of urinary bladder MALT lymphoma, and a success of antibacterial therapy in selected cases suggest the link between urinary tract infection and urinary bladder MALT lymphoma.