A CASE REPORT ON PRIMARY RENAL LYMPHOMA - A DIAGNOSTIC DILEMMA

Received 2024-02-26; Accepted 2024-08-04; Published 2025-01-02

Abstract

Primary Renal Lymphoma (PRL) is diagnosed when lymphoma affects the kidneys and there is no evidence of lymphatic manifestation outside the kidneys. PRL is very rare, with an incidence of less than 1%. This case report highlights Computed Tomography (CT) features of PRL in a 68-year-old female with histology-confirmed renal lymphoma. She presented with worsening left flank pain for two months, associated with constitutional symptoms. Abdominal examination reveals a tender mass in the left hypochondriac region, extending to the left lumbar region. Ultrasound revealed an irregular, solid hypoechoic lesion with cystic spaces in the left kidney. Multiphasic CT renal revealed a large ill-defined mass with poor enhancement in both corticomedullary and nephrographic phases, with no significant washout in the delayed phase. It has a low attenuation value of +30 to +50HU on non-enhanced CT and contains no calcification. Meanwhile, in other renal malignancies, particularly Renal Cell Carcinoma (RCC), a renal mass will exhibit significant enhancement with contrast washout in the delayed phase. RCC often demonstrates early infiltration into the Inferior Vena Cava (IVC). The patient is treated with chemotherapy, and a follow-up Positron Emission Tomography-Computed Tomography (PET-CT) presents a smaller left renal mass. In conclusion, a hypovascular renal mass on CT should raise the suspicion of a PRL, and early tissue diagnosis is important to avoid unnecessary nephrectomy.