Here, we present a case of primary endometrial lymphoma diagnosed in a 49-year-old postmenopausal female who was referred to hematology/oncology service for the evaluation of incidental findings of malignant-looking cells on a Pap smear followed by a cervical polyp biopsy that was suggestive of high-grade B-cell lymphoma (Ki-67: 80-90%) on routine screening. The gene discussed is MKI67; the disease is B-cell non-Hodgkin lymphoma.