CD5-positive DLBCL diagnosed in a 74-year-old woman via uterine drainage fluid analysis

ObjectiveCases of diffuse large B-cell lymphoma (DLBCL) of the uterus co-expressing CD5 are exceedingly rare and diagnostically challenging due to its nonspecific clinical and radiological features, which often mimic other uterine malignancies. This study retrospectively analyzes the cytopathological and histopathological characteristics of this entity in uterine cavity drainage fluid to facilitate its recognition.MethodsWe analyzed a case of uterine CD5-positive DLBCL by collecting clinical data, imaging findings, cytology from uterine drainage fluid, and histology from endometrial curettage. A review of the pertinent literature on uterine DLBCL was also performed.ResultsA 74-year-old woman presented with a two-week history of abdominal distension and anorexia. Abdominal CT demonstrated uterine enlargement with a large fluid collection and multiple enlarged abdominal lymph nodes. Cytology of the uterine drainage fluid revealed numerous atypical lymphoid cells with large, hyperchromatic nuclei, scant basophilic cytoplasm, and a high nuclear-to-cytoplasmic ratio. Histology of the curettage specimens showed a diffuse infiltrate of large lymphocytes with necrosis. The tumor cells exhibited round, oval, or irregular nuclei, coarse chromatin, and prominent nucleoli. Immunohistochemically, the cells were positive for CD20, CD79α, CD19, PAX5, CD5, Bcl-6, and MUM1, and negative for CD3, CD10, Bcl-2, CD30 and Cyclin D1. In situ hybridization for Epstein-Barr virus-encoded small RNA (EBER) was negative. The Ki-67 proliferation index was 90%. These findings supported a diagnosis of CD5-positive DLBCL, non-germinal center B-cell subtype.ConclusionUterus DLBCL expressing CD5 is an exceedingly rare malignancy. Its diagnosis necessitates a comprehensive approach integrating clinical presentation, imaging, cytomorphology, and immunohistochemistry. Increased awareness of the cytological features of lymphoma in uterine drainage fluid is essential to prevent diagnostic oversight.