Diffuse Large B-cell Lymphoma (DLBCL) involving the Uterine Corpus presenting with Abnormal Uterine Bleeding: A Rare Case Report

Abstract Introduction/Objective Diffuse Large B-cell Lymphoma (DLBCL) is an aggressive type of non-Hodgkin lymphoma. Lymphomas affecting the female genital system are extremely rare, accounting for about 1% of extra-nodal lymphomas, with DLBCL being the most common type. We present a rare case of uterine lymphoma presenting with abnormal uterine bleeding. Methods/Case Report A 50-year-old female presented with abnormal uterine bleeding and fatigue for the past three weeks. Laboratory work-up showed hemoglobin level of 5.5 g/dL. Pelvic ultrasound revealed thickening of the endometrium and a 1.6 cm hypoechoic uterine lesion along with multiple enlarged bilateral adnexal lymph nodes. Histological examination of the endometrial biopsy demonstrated endometrial fragments with diffuse subepithelial proliferation of large, poorly differentiated cells with round nuclear contours, finely dispersed chromatin, relatively inconspicuous nucleoli and moderate amount of cytoplasm. Many scattered mitoses and apoptotic bodies were present. Primary set of immunohistochemical stains were performed to rule out primary uterine epithelial or mesenchymal tumors. The tumor cells were negative for pan-keratin, high and low molecular weight keratins and positive for CD45. Further work-up demonstrated CD20 positivity. It was diagnosed as DLBCL with a non-germinal center, double expressor phenotype and a high Ki-67 proliferation. Fluorescence in-situ hybridization studies were negative for MYC and BCL6 gene rearrangements and IGH-BCL2 translocation. Further radiological workup revealed diffuse lymphadenopathy with multiple pulmonary and renal nodules consistent with Stage IV DLBCL. She was treated with six cycles of R-CHOP regimen, and complete metabolic response was achieved. Results (if a Case Study enter NA) NA Conclusion Uterine lymphomas are very rare and on small biopsies may histologically mimic poorly differentiated uterine malignancies such as dedifferentiated/undifferentiated carcinomas. Adding lymphoma lineage markers to poorly differentiated tumors is recommended to avoid missing such a rare entity.