Perirenal Mass: An Unusual Presentation of Primary Renal Lymphoma

Abstract

Primary renal lymphoma (PRL) is a rare type of Non-Hodgkin's Lymphoma (NHL), with B cell lymphoma being the most common subtype, to date; no more than 100 cases of PRL have been described and less commonly, when the involvement of perirenal space is isolated, without any renal parenchymal infiltration or contiguous abdominal adenopathy. In this article, we report a case of non-Hodgkin’s lymphoma (NHL) in 65-year-old man, presented initially for flank pain, fever and unintentional weight loss associated with dysuria and pollakiuria. Abdominal ultrasound revealed a hyperechoic masse of the left perinephric space without focal lesions in the kidneys. The CT scan confirmed the solid character of the perirenal abnormality. No intra or retroperitoneal lymphadenopathy was noted. Biopsy of the left perirenal mass using local anesthesia was performed under ultrasound guidance. The histopathological report was compatible with non-Hodgkin’s lymphoma and FDG PET-SCAN confirmed the primary localization of renal lymphoma in the left perinephric space. The aim of this work is to report a new case of primary renal lymphoma, as one of neoplasic causes of perirenal masses, describe the spectrum of imaging findings of these entities and discuss how to differentiate it from other causes of perirenal masses.