Diagnosis of Splenic Marginal Zone Lymphoma by Ultrasound and Contrast- enhanced ultrasound: A Case Report and literature review

Background: Splenic marginal zone lymphoma (SMZL) is an extremely rare indolent B-cell lymphoma originating in the spleen, whose clinical detection is difficult. Ultrasound is one of the first methods of clinical routine spleen examination and regular review. Meanwhile, ultrasound contrast examination can clearly show the blood perfusion pattern of spleen tissues and lesions, and provide help for the differential diagnosis of spleen tumor lesions. The ultrasound and contrast-enhanced ultrasound manifestations of SMZL are rarely reported. Case presentation Patient, female, 65 years old，came to the hospital with an enlarged spleen. Laboratory examination in our hospital showed that the lymphocyte count was reduced to 0.54×109/L, the lymphocyte ratio was 0.153. Ultrasonographic findings showed that the spleen was enlarged, with diffuse thickening of parenchymal echo, uneven distribution, in the shape of zonal or grid. There was a mass at the hilum of the spleen. After the infusion of contrast agent Sonovue, the tumor regression was delayed and the overall enhancement pattern was slow in and fast out. Combined with contrast-enhanced ultrasound, the final diagnosis was spleen enlargement with splenic mass, lymphoma? On CT images, the spleen was enlarged and unevenly distributed, and two isodense enhanced foci were observed in the spleen. Pathological findings of bone marrow aspiration in patients: CD20(+), CD3(-), CD138(-), CD38(-) bone marrow hyperplasia was slightly reduced. The patient underwent laparoscopic splenectomy under general anesthesia. Postoperative gross observation showed that the spleen was enlarged and intact. A hard gray nodule with clear boundary was seen in the spleen. Light microscopy showed diffuse proliferation of tumor cells. Immunohistochemical: CD20 (air +), CD3 (-), the BCL - 2 (air +), the BCL - 6 (-), CD10 (-), CD43 (-), CyclinD1 (-), CD21 (-), CD23 (-), Ki67 (+ 8%). Combined with immunomarkers, it was considered as splenic marginal B-cell lymphoma. The tumor invaded two lymph nodes at the splenic hilum. Conclusion: SMZL is rare and difficult early diagnosis due to its insidious symptoms, slow progression. Ultrasound and contrast-enhanced ultrasound can improve the diagnostic rate of SMZL. In this case, ultrasound and contrast-enhanced ultrasound mode can provide reference for clinical ultrasonic diagnosis of SMZL.