Primary extranodal marginal zone B-cell lymphoma in a macroscopically normal fallopian tube.

Primary extranodal marginal zone lymphomas (EMZL) of the fallopian tube are rare. The few published case reports suggest a causal relationship between chronic inflammation and tubal EMZL, with associated abnormal macroscopy noted intraoperatively. We present a woman in her 50s with postmenopausal bleeding and endometrial hyperplasia who underwent a laparoscopic total hysterectomy and bilateral salpingectomy. Macroscopy of the specimen was unremarkable. Microscopy of the right fallopian tube showed dense infiltrate of monomorphous lymphocytes with mild nuclear membrane irregularity. Immunohistochemical stains found a marked increase in CD20 B cells with Ki-67 <5%. Postoperative positron emission tomography was negative for multifocal involvement. This was consistent with a primary low-grade EMZL of the right fallopian tube. We present a case of a macroscopically normal primary tubal EMZL with no evidence of preceding antigenic stimulus, thus challenging its well-established role in the lymphomagenesis of EMZL.