The renal parenchymal stone: a benign calcified renal mass

Five patients are described, each with a densely calcified solitary mass in a peripheral location in the kidney. There was exophytic projection of the calcification in 4 cases. Three lesions were so completely calcified as to be regarded as stones. The bulk of the lesion was calcified in the 2 other cases, in which the noncalcified portion was either avascular or hypovascular. In no case was there evidence of a soft-tissue mass extending beyond the confines of the calcification. Pathologic correlation in 1 case showed only calcification in association with some renal scarring, and in a second case demonstrated an old organized and calcified abscess. Long-term follow-up in the other 3 cases has demonstrated complete stability without evidence of tumor. All cases are believed to represent examples of calcified renal parenchymal scars, resulting from old granulomatous disease, renal abscess, or hematoma. We propose that these lesions be regarded as solitary renal parenchymal stones without malignant potential, rather than calcified masses. The significance of the findings for patient management are discussed.     

Pleural calcification: a type of "metastatic calcification" in chronic renal failure

Pulmonary calcifications associated with chronic renal failure are rare conditions. However, a few such cases have been reported in the literature, and they were regarded as a sign of secondary hyperparathyroidism. Pleural calcification induced by secondary hyperparathyroidism has not been reported in the literature. We report four cases of slow-growing pleural calcification which are considered to have been induced by hyperparathyroidism, in patients undergoing maintenance haemodialysis for chronic renal failure. CT scan was useful for the detection of calcified lesions in the pleura.     

A case of septic pulmonary embolism associated with renal abscess mimicking pulmonary metastases of renal malignancy

We report the case of a 46-year-old woman with acute febrile symptom who had multiple pulmonary nodules and a renal mass. She underwent ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to find a hidden malignancy and the cause of her fever. FDG PET/CT images demonstrated a renal mass and multiple lung nodules with intense FDG uptake, which was suspicious of a renal malignancy with multiple pulmonary metastatic lesions. CT-guided biopsies of the pulmonary and renal lesions only showed chronic inflammatory infiltrates without evidence of malignancy. She was diagnosed with septic pulmonary embolism from a renal abscess. One month after antibiotic treatment, the follow-up chest and abdomen CT showed improvement of the lung and renal lesions. This is the first case demonstrating the FDG PET/CT finding of septic pulmonary embolism associated with renal abscess in the published literature.     

Malacoplakia of the urinary tract with renal parenchymal involvement

Malacoplakia is a distinct pathologic lesion usually involving the urinary bladder. The lesions consist of smooth, yellowish brown plaques in the mucosa varying from 0.1 to 0.3 cm in diameter. The lesion was first described by Michaelis and Gutmann in 1902, and was subsequently named malacoplakia (“soft plaque”) by von Hansemann in 1903. This report describes a case of renal parenchymal malacoplakia presenting on excretory urography as a cystic renal mass associated with malacoplakia involving the ureter and bladder. The usual urographic differential diagnoses of a cystic renal mass include cystic renal cell carcinoma, mutilocular cyst, benign cystic nephroma, hemorrhagic cyst, hematoma, and renal abscess. In patients, especially females, with a renal mass associated with a history of repeated urinary tract infections, altered immune syndromes, abnormal cystoscopic findings, or filling defects in the collecting system or urter, renal parenchymal malacoplakia should be included in the differential diagnosis.     

Computed tomography of renal lymphoma

The CT studies of 29 patients with renal or perirenal lymphoma were retrospectively reviewed. Four patterns of disease were identified. Seventeen of 29 patients (59%) had bilateral renal masses. Only seven of these patients had associated enlarged retroperitoneal lymph nodes. Eight patients (28%) had single renal or perirenal lesions adjacent to or contiguous with bulky retroperitoneal lymphadenopathy. Three patients had infiltration of the perirenal space without significant renal parenchymal involvement, and one patient had a solitary renal mass. No patients in this series had diffuse involvement of the kidney without a focal mass. Renal involvement with lymphoma should be considered in any patient who develops multiple homogeneous solid renal or perirenal masses, even in the absence of other retroperitoneal disease.     

The radiologic and clinical aspects of calcified hypernephroma.

The radiologic, pathologic, and clinical findings were reviewed in 18 patients with calcified hypernephroma and 6 with calcified benign renal lesions. Our results suggest: (a) that the pattern of calcification in a renal parenchymal lesion is of little assistance in diagnosis; in this series, many hypernephromas had peripheral curvilinear calcifications, and most benign renal lesions had internal amorphous calcifications; (b) that no distinct angiographic pattern exists in calcified hypernephroma, and a spectrum ranging from avascular to hypervascular may be identified; and (c) that these tumors may behave more benignly than uncalcified hypernephroma (5-year survival 78%).     

Calcified renal metastases: their etiology, pathogenesis, computed tomographic aspects and differential diagnosis

PURPOSE: To describe CT findings of calcified renal metastases focusing on differential diagnosis problems. MATERIAL AND METHODS: We retrospectively reviewed abdominal CT scans of 8000 patients with tumor, performed from 1984 to 1998. Among the 58 renal metastases, 9 showed a calcific component. We evaluated the location, morphostructural pattern, histology of the primary lesion, the synchronous or metachronous character and the type of treatment. All the lesions were pathologically proved. RESULTS: The primary histotype of the 9 metastases was as follows: 4 mucin-producing adenocarcinomas of the large bowel, 1 gastric mucinous adenocarcinoma, 1 chondrosarcoma, 1 osteosarcoma, 1 melanoma, 1 papillary thyroid carcinoma. In all the cases the renal metastasis was unilateral and unifocal. Granular multiple calcifications were demonstrated within the metastases of mucin-producing adenocarcinoma of the large bowel (3), within the metastasis of chondrosarcoma (1) and of melanoma (1). Diffuse "star-like" calcifications were demonstrated in renal metastases of mucin-producing adenocarcinoma of the large bowel and of gastric mucinous adenocarcinoma (1). Peripheral "egg-shell" calcifications were demonstrated in renal metastasis from papillary thyroid carcinoma (1). Completely calcified monofocal calcification was demonstrated in renal metastasis from osteosarcoma (1). DISCUSSION AND CONCLUSIONS: Calcified renal metastases are rare lesions related to specific oncotypes. The differential diagnosis (carcinoma with calcifications, osteosarcoma, chondrosarcoma, nephrocalcinosis, granulomatosis, hydatidosis etc.) is particularly difficult because of the aspecificity of the morphostructural pattern. Diagnosis is based on a history of specific oncotypes (papillary and mucin-secreting carcinomas, osteosarcoma and chondrosarcoma), but in most cases it requires pathologic confirmation.     

CT of parapelvic cystic renal cell carcinoma.

Parapelvic renal cysts are benign ubiquitous lesions of the renal sinus frequently demonstrated on CT and ultrasonography. Occasionally a renal parenchymal mass will grow so that its epicenter is within the renal sinus. We report two cases of surgically proven cystic renal cell carcinoma centered in the renal sinus with no apparent connection to the renal parenchyma. Cystic renal cell carcinoma must be excluded whenever a parapelvic cyst with atypical features is encountered on cross-sectional imaging studies.     

肾占位性病变的CT鉴别诊断

目的：分析肾占位性病变的CT表现，探讨CT对该类疾病的鉴别诊断价值。方法：对手术／病例证实的28例肾占位性病变进行回顾性分析，所有病例均行平扫和增强扫描。结果：肾恶性肿瘤21例(75％)，其中肾癌(RCC)16例，CT表现为肾实质内形态不规则的低密度软组织肿块，增强后不强化或轻度强化；肾盂癌2例，CT表现为肾盂内软组织肿块影，增强后不强化或轻度强化。肾母细胞瘤(Wilms瘤)3例，CT表现为较大不规则的分叶肿块，增强后不强化；肾良性肿瘤3例(11％)，均为肾血管平滑肌脂肪瘤(ALL)，2两例CT表现为多种不同成分的混杂密度肿块，1例表现为均匀等密度肿块，增强后软组织部分强化，而脂肪成分不强化。其它4例(14％)，3例肾囊肿，CT表现为典型的边界清楚的囊性病灶，增强后未见强化：1例肾脓肿，CT表现为实质性与囊性混杂密度的肿块，增强后实质性部分有轻度强化，囊性部分不强化。结论：CT平扫及增强扫描，以及诊断过程中密切结合病史，对肾占位性病变有重要的鉴别诊断价值。     

螺旋CT在小肾癌诊断中的价值

目的评价螺旋CT多期扫描在小肾癌诊断中的价值。方法收集经手术病理证实的小肾癌14例,分析其螺旋CT平扫、皮质期、实质期及肾盂期的表现。结果CT平扫病灶呈等密度7例,稍低密度5例,稍高密度1例,1例为囊实性肿块,其中2例伴斑点状钙化。增强扫描皮质期12例呈明显强化,2例呈轻中度强化。肾实质期肿瘤密度迅速减退,肾盂期肿瘤密度进一步减退。结论小肾癌螺旋CT增强多期扫描征象有一定特征性,对小肾癌的诊断有重要价值。     

螺旋CT扫描在小肾癌诊断中的应用价值(附14例报告)

目的探讨螺旋CT多期扫描在小肾癌诊断中的价值。方法收集经手术病理证实的小肾癌14例,行螺旋CT平扫和皮质期、实质期及肾盂期增强扫描,分析其表现。结果CT平扫病灶呈等密度9例,稍低密度4例,稍高密度1例,2例为囊实性肿块,其中1例伴斑点状钙化。增强扫描皮质期11例呈明显强化,3例呈轻中度强化。肾实质期肿瘤密度迅速减退,肾盂期肿瘤密度进一步减退。结论小肾癌螺旋CT增强多期扫描征象有一定的特征性,对小肾癌的诊断有重要价值。     

原发性乳腺淋巴瘤的CT及MR表现

目的探讨原发性乳腺淋巴瘤的CT及MR特征,提高对本病影像学表现的认识。方法回顾性分析经病理证实的14例原发性乳腺淋巴瘤患者的CT及MR资料,年龄32～77岁,中位年龄54岁。所有患者皆行CT增强扫描,其中6例行MR检查。结果14例病灶大小2．2～11．5cm。所有病变密度或信号均匀,未见毛刺及钙化。其主要有三种表现：①单发结节或肿块型：占64．3％（9/14）。增强CT除1例呈环形伴结节样强化外,其他皆均匀中等度强化。乳头未见凹陷,皮肤未见增厚,乳后间隙未见侵犯。MRI脂肪抑制T。wI表现为稍高信号,DWl显示扩散明显受限,ADC值显著降低,约0．45×10^-3m㎡/s～0．73×10^-3m㎡/s,时间～信号曲线均呈平台型（Ⅱ型）曲线;②多发肿块型：占14．3％（2/14）。病灶直径较大,为数个结节融合所致。密度信号改变同单发结节或肿块型相似,但占位效应明显,乳后问隙狭窄;③弥漫型：占21．4％（3/14）。病灶直径巨大,范围广泛,可累及两个乳腺象限至整个乳腺,占位效应最明显。病灶强化不均匀,MR脂肪抑制T2WI见高信号分隔,增强后分隔明显强化,可伴有乳后间隙受侵,皮肤广泛增厚,但乳头未见凹陷。结论原发性乳腺淋巴瘤的影像学表现具有一定的特征性。当出现乳腺内无毛刺及钙化的结节、肿块,MRIT2WI脂肪抑制序列呈稍高信号,ADC值显著降低、或伴一侧乳腺皮肤广泛增厚而无乳头凹陷,应考虑原发性乳腺淋巴瘤可能。     

CT and MRI in fat-containing papillary renal cell carcinoma

We present a case, pathologically proven, of a patient with multiple papillary renal cell carcinoma (PRCC) with bilateral and synchronous affectation. CT showed fatty tissue inside one of the lesions and numerous calcified lesions. The study with MR demonstrated multiple and hypointense lesions in T2 and contrast enhancement in T1. Our observations confirm that the presence of multiple lesions with fat and calcified deposits and poor contrast enhancement should be diagnosed as PRCC, rather than renal clear cell carcinoma (RCCC) or renal angiomyolipoma.     

肾结核的多层螺旋CT动态增强影像特征

目的分析肾结核多层螺旋CT动态增强的影像表现,并提高其诊断水平。方法 20例肾结核(累及双肾10例)患者均经多层螺旋CT平扫及3期增强扫描(皮质期、实质期、肾盂期)。结果在20例的30个病肾中,肾实质密度不均匀29个肾,不同形态钙化15个肾,集合系统不成比例扩张积液14个肾,呈"花瓣"状排列10个肾,合并输尿管上段管壁增厚5个肾,对侧肾积水3个肾,肾脏形态改变28个肾,肾皮质变薄26个肾。3期动态增强扫描显示皮质期及实质期强化程度减低密度不均匀15个肾,肾盂、肾盏、脓腔壁环状强化10个肾。肾盂期,9个肾无造影剂进入集合系统及脓腔,6个肾造影剂进入肾盂、肾盏、脓腔。结论肾结核多层螺旋CT的影像表现多种多样,多层螺旋CT能很好地显示结核病变部位、范围及双肾功能情况,可为临床准确诊断提供重要依据。     

Cryptococcus meningoencephalitis in AIDS: parenchymal and meningeal forms

CT and MRI in one case of Cryptococcus neoformans infection showed contrast-enhancing parenchymal lesions resembling granulomata or abscesses. After an initial phase without contrast enhancement, the full extent of the lesions was visible within 2 weeks of presentation. The enhancing masses were assumed to represent intracerebral cryptococcomas. Despite evidence of massive meningeal infection on cerebrospinal fluid (CSF) examination, no radiological signs of meningitis, invasion of the Virchow-Robin spaces or ventriculitis could be demonstrated. With antimycotic treatment the contrast enhancement disappeared and cystic, partly calcified lesions remained. Recurrence of meningeal infection without radiological correlates was apparent in this stage. In a second case of proven cryptococcus meningitis, dilation of Virchow-Robin spaces or cysts in the adjacent parenchyma were the main abnormalities on MRI. Enhancing masses were not detected. These cases may represent two different reactions of the immunocompromised hosts to infection with C. neoformans: widening of the perivascular spaces as a correlate of the more typical meningeal infection and enhancing parenchymal lesions as a sign of further invasion from the CSF spaces. Enhancement of cryptococcomas, indicating an inflammatory response in the surrounding brain, is not typical in patients with impairment of immune function. Received: 11 March 1998 Accepted: 19 June 1998     

MR imaging of calcified intracranial lesions

Fifty calcified intracranial lesions diagnosed with computed tomography (CT) were evaluated with magnetic resonance (MR) using a spin-echo sequence. MR images demonstrated 41 of 50 lesions seen as calcified on CT scans, among them 29 of 30 cerebral neoplasms and all ten arteriovenous malformations. The presence of calcification was suspected prospectively in about 60% of calcified lesions but was also suspected in 45% of uncalcified lesions (reviewed as control cases). No fine calcifications and only 25% of punctate calcifications were disclosed on MR images. In the nine lesions undetected by MR, calcification was the only abnormal CT finding. The findings of calcification on MR images were nonspecific, ranging from signal void or signal dampening on all sequences to no alteration of signal intensity. The most common finding of calcification was a focus of signal diminution, rather than signal void, as commonly reported.     

Renal cell carcinoma containing macroscopic fat on CT mimics an angiomyolipoma due to bone metaplasia without macroscopic calcification

We report a case of renal cell carcinoma (RCC) containing foci of macroscopic fat, which were pathologically proven to be areas of osseous metaplasia. The macroscopic fat was not associated with calcification on the pre-operative CT scan. To our knowledge, there are no reported cases of RCC that contain osseous metaplasia without evidence of macroscopic calcification on CT. The finding is significant because standard imaging practice is to classify a renal mass containing intratumoral macroscopic fat that is not associated with calcification, ossification or invasion of perirenal or hilar fat as an angiomyolipoma.     

Retroperitoneal abscess caused by dropped renal stones

Staghorn calculi account for about 4% of presenting renal stones in developed countries, are source of recurrent urinary tract infection, and may be eventually treated by surgical stone removal. A 55-year-old female with a history of staghorn renal calculi and recurrent urinary tract infections presented with a left flank and lower abdominal pain following recent left robotic partial nephrectomy and nephrolithotomy. Contrast-enhanced computed tomography (CT) of the abdomen demonstrated a large left-sided retroperitoneal fluid collection with a few dropped renal stones in the dependent portion of the collection. The patient treated with early percutaneous drainage of the collection and antibiotic treatment and responded well clinically. The clinical and imaging presentation of a rare case of retroperitoneal abscess formation caused by dropped renal stones is described in this study. Imaging, particularly ultrasound and CT, plays a key role in detecting the dropped renal stones and can help with differential diagnosis and treatment plans.     

Renal involvement in multifocal osteosarcoma

A rare case of multifocal osteosarcoma metastatic to kidney, lung and lymph nodes is presented. Radiological findings included multiple foci of sclerotic lesions involving the axial and peripheral skeleton, a heterogeneous renal mass with areas of calcification, multiple pulmonary metastases with pneumothorax, and partially calcified enlarged mediastinal and abdominal lymph nodes.     

Observations on the growth of renal neoplasms

A retrospective review of the imaging results of 11 patients with 13 solid renal parenchymal neoplasms was performed, allowing analysis of the linear growth rates of these tumors. The study sample included seven pathologically proved renal adenocarcinomas and six lesions that were indicative of a neoplasm radiologically (enhancing parenchymal mass on computed tomographic [CT] scans with documented interval growth), which were followed up for 2-7.8 years. Variable interval tumor growth was demonstrated in every case except one and ranged from 0 to 1.6 cm/y, with an overall mean linear growth rate of approximately 0.5 cm/y. Ten of 11 "small renal neoplasms" (less than or equal to 3.0 cm in diameter) displayed interval growth, with five ultimately measuring greater than 3.0 cm (size range, 3.5-7.0 cm). While the results are preliminary and reflect observations on a very small study sample, it was noted that five of the seven pathologically proved adenocarcinomas appeared homogeneous and well marginated, and all were low-grade, low-stage carcinomas. These grew more slowly and were generally smaller at initial presentation than higher-grade lesions, which demonstrated a more heterogeneous appearance on CT scans.