Primary B-cell lymphoma of the uterine cervix: Presentation in Pap-test slide and cervical biopsy.

This case involved a 69-year-old female who presented with irritative urinary voiding. Imaging studies showed an 18-cm uterine mass centering on the cervix and extending into the bladder. The Pap test slide demonstrated necrotic background and degenerative changes in single and grouped atypical "small round blue cells" with high nuclear/cytoplasm ratio, scant cytoplasm, and hyperchromatic focally cleaved nuclei with occasional nuclear membrane "snout projections." Cervical biopsies showed similar findings. The tumor cells were positive for CD45, CD20, and PAX-5, and negative with epithelial, neuroendocrine, and muscle markers. A Ki-67 immunostain showed a markedly elevated proliferative index and the MUM1 stain was diffusely positive. Molecular study identified clonal immunoglobulin heavy chain gene rearrangement. Owing to its rarity, cervical lymphoma may sometimes be confused with other types of malignant neoplasms or inflammatory processes. Therefore, it is important to recognize the cytological features of cervical lymphomas and be aware of the potential diagnostic pitfalls for timely diagnosis and therapy. Diagn. Cytopathol. 2017;45:235-238.