case
•男性，46岁，
•患者2周前在当地体检发现左肾占位
•患者自发病以来无尿频、尿急、尿痛、腰痛、发热等症状
•无体重变化，大小便正常，睡眠良好
镜检：瘤内为淋巴样细胞，体积较小，核类圆，排列密集，呈浸润性生长
结果：（左侧）肾脏恶性淋巴瘤（弥漫大B细胞型）
•Yasunaga[1]等提出肾脏原发性淋巴瘤诊断标准
–肾脏肿物经病理证实为淋巴瘤
–就诊时无淋巴结以及内脏器官等淋巴瘤肾外侵犯
–无白血病性血象以及骨髓抑制表现
多结节型 30-50%
•肿瘤细胞浸润后再增殖
•可形成单侧多个病灶或双侧病灶
•可位于肾皮质、髓质
•无包膜边界清，病灶呈圆形或类圆形，或融合状
•无论结节大小，占位效应不显著
CT表现
平扫：等、低、稍高密度，有时无法显示多发病灶；
增强：皮髓交界期轻度强化—-确定病变性质
实质期最佳时期—确定病变数目、形态、边界、均匀度
MR表现
T1WI：呈低信号、等信号或稍高信号;
T2WI：呈等或低信号;
肿瘤信号相对均匀、坏死少见，无包膜;
DWI：显著高信号（与水分子运动受限有关）;
增强：轻度强化
Figure1.Large B-cell lymphoma in a 41-year-old HIV-positive man. (a) Unenhanced CT scanof the midabdomen shows a soft-tissue mass (arrowhead) in the region of thegreat vessels, a finding that is suspicious for retroperitoneal adenopathy. Thekidneys do not demonstrate any abnormality in contour. (b) Contrast-enhanced CTscan of the midabdomen shows bilateral soft-tissue renal masses (arrows).Note that these masses do not deform the contour of the kidneys. The paraaorticretroperitoneal adenopathy (arrowhead) is much more clearly depicted than in a.
Figure2.High-grade B-cell lymphoma in a 38-year-old human immunodeficiency virus(HIV)–positive woman who presented with abdominal pain and distention. (a)Contrast material–enhanced CT scan of the midabdomen shows a very largesoft-tissue mass (arrows) infiltrating the mesenteryand omentumand displacing the small bowel and colon. (b) Contrast-enhanced CT scan showshypoenhancing soft-tissue masses (arrows) in both kidneys. Note also theretroperitoneal adenopathy (arrowhead). (c) Photomicrograph of a specimenobtained at fine-needle aspiration biopsy shows hypercellularity with a uniformpopulation of malignant lymphocytes. Numerous aptotic cells are also seen(×200HE)
Figure3.Magnetic resonance imaging of the kidneys. (A) T1-weighted imaging reveals twoslightly hypointense or isointense signal masses in the right kidney and onehypointense signal mass in the left kidney. (B) T2-weighted imaging revealshypointense signal in the bilateral renal masses shown in (A). (C)Contrast-enhanced T1-weighted imaging reveals poor enhancement of the bilateralrenal masses shown in (A).
单结节型 25-30%
肿瘤呈灶性增殖，一般形成单侧单发病灶
影像表现
平扫：等、低、稍高密度，境界欠清；
增强：强化方式多样，可为富血管、中等血供、少血供;
位于肾包膜下孤立结节可沿包膜浸润，形成包膜尾征
Figure4.Large B-cell lymphoma in a 72-year-old man with a history of prostate cancer.Contrast-en- hanced CT scan of the kidneys shows a well-defined expansile mass(arrow) in the left kidney. No other solid renal masses are seen, but the rightpsoas muscle (arrowhead) is enlarged. The diagnosis was established withUS-guided percutaneous biopsy of the renal mass.
•腹膜后巨大软组织肿块侵犯附近肾脏，包绕肾门和肾血管
影像表现
平扫：形态不规则，实变、坏死、囊变、出血少见；
肾脏病灶与腹膜后肿块可分开也可融合；
增强：轻中度强化;
动态增强呈进行性延迟强化，肿瘤内依稀可分辨肾门，肾门血
管走形、形态正常
Figure5.Low-grade B-cell lymphoma in a 60-year-old man. The patient underwent abdominalCT for necrotizing pancreatitis. (a) Venous phase contrast-enhanced CT scanshows a large soft-tissue mass (arrow) infiltrating the retroperitoneum,encasing the left renal vessels, and extending into the perinephric space. Notethe fluid collection (arrowhead) in the pancreatic bed, a finding that isconsistent with the patient’s history of pancreatitis. (b)Excretory phase contrast-enhanced CT scan shows a pararenal mass (arrow) withsoft-tissue attenuation. Note also the absence of hydronephrosis. Althoughpancreatitis commonly affects the perirenal and pararenal spaces, the soft-tissueattenuation of the mass in this case led to the correct diagnosis of lymphoma.The diagnosis was confirmed with US-guided biopsy。
Figure 6. Large B-cell lymphoma in a 52-year-old man with a history of chronic lymphocytic leukemia.Contrast-enhanced CT scan shows bulky retroperitoneal adenopathy (black arrows). A soft-tissue mass (white arrow) is seen in the right renal sinus fat and the perinephric space. Note the delayed enhancement of the right kidney.
肾周型 少见
•肿瘤沿着肾周筋膜生长;
•可侵犯或不侵犯肾脏皮质
CT表现
平扫：淋巴瘤主要位于肾脏周围，形成肿块或不规则软组织肿块，肾
脏被肿瘤“封入”；
增强：可侵犯或不侵犯肾脏皮质，增强有助于鉴别两者关系
Figure 7. Perinephric disease in a 66-year-old man with an incidental finding of a left renal mass. (a) Unenhanced CT scan shows marked enlargement of the left kidney (arrows). Left paraaortic lymph nodes (arrowhead) are seen encasing the left renal vein. (b) Corticomedullary phase contrast-enhanced CT scan shows a large hypovascular mass (arrows) located primarily in the perinephric space. The mass appears to invade the left renal parenchyma. (c) Photomicrograph of a specimen obtained at core biopsy shows numerous lymphocytes with focal nuclear crush artifact infiltrating dense fibrous tissue (arrow) (×100; HE).
Note that there is no significant enhancement delay in the left renal parenchyma relative to the right kidney. Arrowhead indicates paraaortic lymph nodes encasing the left renal vein.
Figure 8. B-cell lymphoma in a 62-year-old man with a history of follicular lymphoma. Routine follow-up CT was performed. (a) Portal venous phase contrast-enhanced CT scan shows a mildly enhancing mass (arrow) in the right anterior pararenal space. The mass represented a new finding. (b) Portal venous phase contrast-enhanced CT scan shows stranding in the mesenteric fat (arrows), a finding that suggests a “misty mesentery.” This finding was also new. US-guided biopsy of the perirenal mass demonstrated aggressive B-cell lymphoma.
•肿瘤细胞沿着沿着肾脏间质组织支架呈浸润性生长;
•肾脏体积增大但形态正常;
CT表现
平扫：肾脏体积弥漫性增大，但形态正常，密度减低；
增强：轻中度不均匀强化
MR表现
T1WI：呈低信号、等信号或稍高信号;
T2WI：呈等或低信号;
增强：增强早期肾皮质相对正常，肾皮髓交界相延迟，后期皮髓交界
相消失，肾脏轮廓增大
Figure 9. Primary renal lymphoma in a 41-year-old HIV-positive man who presented with renal failure. Nephrographic phase contrast-enhanced CT scan of the kidneys shows bilateral renal enlargement. Heterogeneously decreased enhancement of the renal parenchyma is also seen. The diagnosis of Burkitt-like lymphoma was established with renal biopsy.
Figure 10. Infiltrative renal lymphoma in a 44-year-old woman. Cont|rast-enhanced CT scan shows the kidneys as diffusely enlarged and replaced by tumor.The lobulated appearance of the tumor reflects the transition to a more focal expansile mass as it compresses and destroys renal parenchyma.
