unilateral lower extremity swelling as an unusual presentation of non-hodgkin’s b-cell lymphoma

Non-hodgkin’s b-cell lymphoma is a hematological condition with different types based on clinical presentation, pathological features, and therapeutic response, like diffuse large b-cell lymphoma (dlbcl), follicular lymphoma, and chronic lymphocytic leukemia (cll). we report a 33-year-old male presented with a complaint of unilateral leg swelling, firstly supposed to be a deep vein thrombosis (dvt); however, in multiple doppler ultrasonography, dvt was ruled out. the patient’s precise history revealed a swollen mass in the left knee region for two months that slowly enlarged and was confirmed with a physical examination. doppler ultrasonography of the lower extremities conducted in our center presented no sign of deep vein thrombosis; however, it demonstrated some complex conglomerate lymph nodes in the left inguinal compressing the ipsilateral femoral and iliac vein. it also revealed bulky adenopathy, with a 95×65 mm left knee mass. the performed biopsy reported the existence of malignant lymphoma, suggesting the existence of dlbcl. consequently, he was referred to a hematology/oncology department for appropriate treatment. this unusual presentation of dlbcl and the importance of noticing an accurate history taking and physical examination, instead of conducting unnecessary paraclinical tests (several doppler ultrasonography in this case), have led us to report this case.