【双语病例】髓质海绵肾（IVP、CT）鉴别诊断往期相关链接：【书摘】“肾皮/髓质钙质沉着症”的鉴别诊断History: A 75-year-old man with a chronic history of microhematuria was referred for a CT urogram by his urologist.病史：75岁男性，长期镜下血尿，泌尿外科医生建议其行CTU检查。
Scout, coronal precontrast, axial nephrographic/excretory phase images, and volume-rendered coronal reconstructions of the left and right kidneys are shown below.定位像、冠状平扫、轴位排泄期图像及左、右肾冠状VR重建如下所示。
Additional history: The patient has a prior history of microhematuria and kidney stones. Review of the PACS for prior imaging reveals an intravenous pyelogram (IVP) from 2005. Scout and postcontrast exposures are shown below.病史补充：患者之前患有镜下血尿及肾结石。
回顾PACS中2005年的静脉尿路造影（IVP）图像，腹部平片及造影后图像图像所示。
Findings 影像表现CT urogram (2017): Noncontrast images demonstrate multiple bilateral nonobstructing renal calculi, the largest measuring 6 mm in the right kidney. Some of the calcifications could represent nephrocalcinosis -- for example, those in the upper pole of the right kidney. The kidneys show symmetric enhancement without suspicious renal mass. Multiple bilateral exophytic simple renal cysts are noted, the largest in the midpole of the right kidney measuring 3.6 x 4.3 cm. There are additional subcentimeter low-attenuation lesions that are too small to characterize. There is a'paintbrush sign' appearance to the renal medullae in keeping with a history of medullary sponge kidney. There is mild bladder wall thickening and trabeculation that may be related to chronic outlet obstruction. Further evaluation is deferred to cystoscopy.CTU：CT平扫可见双肾多发非梗阻性肾结石，右肾最大者直径约6mm，其中一些钙化可能代表肾结石，例如，右肾上极的那些。
肾脏对称性强化，未见可疑肾肿物。
双肾可见多发单纯性肾囊肿，大者位于右肾中部，大小约3.6 x 4.3 cm；另可见不足1cm的低密度灶，其太小而不能显示。
肾髓质表现为“毛刷征”，符合髓质海绵肾。
膀胱壁轻度增厚并小梁形成，与慢性流出道梗阻有关。
进一步评估需膀胱镜检查。
IVP (2005): Preliminary scout images demonstrate a cluster of at least three radiopaque stones in the upper pole of the right kidney; the largest two stones in this cluster each measure 6 mm in diameter. In addition, there are probable clusters of smaller stones in the interpolar right kidney and right lower pole. Following the uneventful intravenous administration of 150 mL of nonionic contrast material, prompt nephrograms develop, which show the kidneys to be normal in size, shape, appearance, and internal architecture. There is diffuse bilateral tubular ectasia. Contrast is excreted promptly into otherwise normal-appearing pyelocalyceal systems. The calculi are no longer seen and likey reside in dilated tubules. The ureters are normal in course, caliber, and appearance. The urinary bladder has a mildly trabeculated appearance. There are two small urinary bladder diverticula: one of the bladder dome and one arising from the left lateral bladder wall. No filling defects are seen.IVP：预扫定位像可见右肾上极至少3个阳性结石，簇状分布，最大的两个直径约6mm。
另右肾中部及下极可见成簇的小结石。
静脉注射非离子型对比剂150ml，立即摄片，可见肾脏大小、形态、表现及内部结构正常，可见弥漫性双侧肾小管扩张，造影剂进入正常的肾盂肾盏系统。
钙化并未显示，可能在扩张的肾小管内。
输尿管走行、直径及表现正常，膀胱轻度小梁形成，可见两个小膀胱憩室，一个位于膀胱顶壁，一个位于左侧壁；未见充盈缺损。
Differential diagnosis•Medullary sponge kidney•Nephrocalcinosis•Renal cortical necrosis•Renal papillary necrosis•Renal tuberculosis•Oxalosis•Renal pyramid 'blush': Normal homogeneous enhancement of pyramids with no tubular dilation鉴别诊断：•髓质海绵肾•肾结石•肾皮质坏死•肾乳头坏死•肾结核•草酸盐沉着症•肾锥体充盈：肾锥体正常均匀强化，无肾小管扩张Diagnosis: Medullary sponge kidney最后诊断：髓质海绵肾Key pointsMedullary sponge kidney (MSK)Pathophysiology•Medullary sponge kidney refers to a sporadic condition in which the medullary and papillary portions of the collecting ducts are dysplastic and dilated and, in most cases, develop medullary nephrocalcinosis. Occasionally, it can be hereditary.•Patients are predisposed for urinary stasis and resulting urolithiasis.•As many as 33% to 50% of patients have hypercalcemia (i.e., hyperparathyroidism).•The etiology and pathogenesis are unknown.•On cross section, the kidney appears as a sponge and there are multiple cystic cavities in the renal pyramids.o Cysts contain yellow-brown fluid and desquamated cells or calcified material.o Calculi within cysts and their walls consist of calcium oxalate ± calcium phosphate.•The size and number of renal calcifications typically increase with time.•The condition may be bilateral (75%) or unilateral (25%), and it may involve a single pyramid or segment.•The prognosis with MSK is generally good and patients will typically lead a normal life unless complications ensue. Complications include infection, extensive calculus formation, renal insufficiency, and renal failure.病理生理髓质海绵肾（MSK）多散发，是指肾髓质及肾乳头部分的集合管发育不良并扩张，大部分情况下，可合并髓质肾结石。