Primary parenchymal squamous cell carcinoma of the kidney:A case report

BACKGROUND Primary squamous cell carcinoma(SCC)of the renal parenchyma is extremely rare,with only nine cases reported.CASE SUMMARY This study reports a 51-year-old man with primary SCC of the renal parenchyma.The patient was admitted with recurrent dull pain and discomfort in the right lumbar region,which had worsened over 2 weeks,accompanied by painful gross hematuria.SCC antigen(SCCA)levels were elevated,and imaging revealed a renal mass with associated calculi.The patient underwent laparoscopic unilateral nephrectomy and lymph node dissection.Postoperative pathology confirmed highly differentiated SCC with necrosis in the right renal parenchyma,with negative renal pelvis and ureter.The pathological stage was Pt3aN1M0.Four months after surgery,the tumor recurred with involvement of the liver,right psoas major muscle,and inferior vena cava.The patient refused chemotherapy and succumbed to the disease 6 months postoperatively due to disease progression.CONCLUSION We report a case of primary SCC of the renal parenchyma,a rare renal malignancy.The clinical symptoms,laboratory tests,and imaging findings are nonspecific,making accurate and timely diagnosis challenging.According to the literature,for patients with renal calculi accompanied by a renal mass,elevated serum SCCA levels,and magnetic resonance imaging showing cystic or cystic-solid masses within the kidney with pseudocapsules and heterogeneous mild enhancement,the possibility of this disease should be considered.

Advances of multidetector computed tomography in the characterization and staging of renal cell carcinoma

Renal cell carcinoma(RCC) accounts for approximately 90%-95% of kidney tumors. With the widespread use of cross-sectional imaging modalities, more than half of RCCs are detected incidentally, often diagnosed at an early stage. This may allow the planning of more conservative treatment strategies. Computed tomography(CT) is considered the examination of choice for thedetection and staging of RCC. Multidetector CT(MDCT) with the improvement of spatial resolution and the ability to obtain multiphase imaging, multiplanar and threedimensional reconstructions in any desired plane brought about further improvement in the evaluation of RCC. Differentiation of RCC from benign renal tumors based on MDCT features is improved. Tumor enhancement characteristics on MDCT have been found closely to correlate with the histologic subtype of RCC, the nuclear grade and the cytogenetic characteristics of clear cell RCC. Important information, including tumor size, localization, and organ involvement, presence and extent of venous thrombus, possible invasion of adjacent organs or lymph nodes, and presence of distant metastases are provided by MDCT examination. The preoperative evaluation of patients with RCC was improved by depicting the presence or absence of renal pseudocapsule and by assessing the possible neoplastic infiltration of the perirenal fat tissue and/or renal sinus fat compartment.

Perfusion computed tomography in renal cell carcinoma

Various imaging modalities are available for the diagnosis, staging and response evaluation of patients with renal cell carcinoma(RCC). While contrast enhanced computed tomography(CT) is used as the standard of imaging for size, morphological evaluation and response assessment in RCC, a new functional imaging technique like perfusion CT(p CT), goes down to the molecular level and provides new perspectives in imaging of RCC. p CT depicts regional tumor perfusion and vascular permeability which are indirect parameters of tumor angiogenesis and thereby provides vital information regarding tumor microenvironment. Also response evaluation using p CT may predate the size criteria used in Response Evaluation Criteria in Solid Tumors, as changes in the perfusion occurs earlier following tissue kinase inhibitors before any actual change in size. This may potentially help in predicting prognosis, better selection of therapy and more accurate and better response evaluation in patients with RCC. This article describes the techniques and role of p CT in staging and response assessment in patients with RCCs.

Erythrocytosis caused by giant chromophobe renal cell carcinoma:a case report indicating a 9.year misdiagnosis of polycythemia vera

Background:Erythrocytosis,a rare paraneoplastic syndrome,generally occurs in patients with clear cell renal cell carcinoma and has never been reported in patients with chromophobe renal cell carcinoma.Case presentation:We report a case of a young man suffering from a giant(22-cm) mass on his left kidney.Because of a history of polycythemia vera,the patient had been treated for the condition for 9 years.Radical nephrectomy was successfully performed,and the postoperative pathologic examination confirmed a diagnosis of chromophobe renal cell carcinoma.Unexpectedly,the symptom of erythrocytosis disappeared after the surgery.Further examination and analysis were performed,and we finally attributed his erythrocytosis to chromophobe renal cell carcinoma.Conclusions:Chromophobe renal cell carcinoma could cause erythrocytosis,but the clear-cut mechanism needs further research.Secondary erythrocytosis such as those related with renal tumors should be taken into consideration during the diagnosis of polycythemia vera.

Chromophobe renal cell carcinoma: Novel molecular insights and clinicopathologic updates

Chromophobe renal cell carcinoma(ChRCC)is the third most common renal cell carcinoma(RCC)subtype,which predominantly occurs in sporadic setting.ChRCCs are considered to originate from the intercalated cell of distal tubules with two main morphological variants,classic and eosinophilic.Most ChRCCs carry a favorable clinical outcome.Histology alone is limited in predicting the behavior of ChRCCs that do not have overtly aggressive morphologic findings such as necrosis and sarcomatoid features.Along with positive CD117 expression,classic ChRCCs generally express diffuse and uniform CK7,while eosinophilic variant demonstrates more heterogeneous CK7 expression(rare or patchy).Multiple losses of chromosomes 1,2,6,10,13,17,and 21 are considered to be the genetic hallmarks of classic and eosinophilic ChRCCs,while chromosomal gains are known to be associated with sarcomatoid ChRCCs.TP53 and PTEN are the two most frequently mutated genes in ChRCCs.The major challenge in the differential diagnosis of ChRCCs includes considerations around the eosinophilic variant(of ChRCCs),where it may share overlapping features with oncocytoma or other recent emergent oncocytic tumors.Most eosinophilic ChRCCs share expression of the recently described biomarkers,LINC01187 and FOXI1,with classic ChRCCs,however,a subset of eosinophilic-like ChRCCs with lower biomarker expression have been demonstrated to harbor MTOR gene mutations.Overall,the morphologic features of ChRCCs and genetic profile with combinations of chromosomal losses and gains suggest this tumor entity to represent a distinct,yet heterogeneous group of renal neoplasms.

Synchronous sporadic bilateral multiple chromophobe renal cell carcinoma accompanied by a clear cell carcinoma and a cyst: A case report

BACKGROUND Renal cell carcinomas are usually unilateral.However,they are bilateral in 2%to 4%of sporadic cases and is considerably more common in familial cases.Synchronous sporadic bilateral multiple chromophobe renal cell carcinoma(CHRCC)with different subtypes is rare.CASE SUMMARY In this case report,we describe a case of synchronous bilateral CHRCC with two histological variants,accompanied by a clear cell carcinoma and a cyst in a 50-year-old male.The patient underwent retroperitoneal laparoscopic bilateral nephron-sparing surgery and there was no serious postoperative renal dysfunction.CONCLUSION We report a rare case of synchronous bilateral CHRCC with two histological variants associated with a clear cell carcinoma and a cyst.

Synchronous bilateral multiple chromophobe cell renal carcinoma complicated with right kidney cyst: a case report

Synchronous bilateral multiple chromophobe cell renal carcinoma is rare; here we report a case diagnosed with bilateral renal multiple tumors complicated with a cyst in the right kidney. Retroperitoneal laparoscopic bilateral nephron sparing surgery was performed and there was no serious postoperative renal dysfunction. Pathological and immunohistochemical diagnoses of both tumors were chromophobe cell renal carcinoma. The patient has been doing well without any evidence of recurrence or metastasis for 6 months.

Kidney re-transplantation after living donor graft nephrectomy due to de novo chromophobe renal cell carcinoma:A case report

BACKGROUND There are few reported cases of allograft nephrectomy due to malignancy followed by successful renal re-transplantation two years later.In this paper,we report a patient who underwent kidney re-transplantation after living donor graft nephrectomy due to de novo chromophobe renal cell carcinoma(ChRCC)involving the allograft kidney.CASE SUMMARY A 34-year-old man underwent living kidney transplantation at the age of 22 years for end-stage renal disease.Maintenance immunosuppression consisted of tacrolimus,mycophenolate mofetil(MMF),and prednisone.Six years posttransplantation,at another hospital,ultrasonography revealed a small mass involving the upper pole of the graft.The patient declined further examination and treatment at this point.Seven years and three months post-transplantation,the patient experienced decreasing appetite,weight loss,gross hematuria,fatigue,and oliguria.Laboratory tests showed anemia(hemoglobin level was 53 g/L).Contrast-enhanced computed tomography revealed a large heterogeneous cysticsolid mass involving the upper pole of the renal allograft.Graft nephrectomy was performed and immunosuppressants were withdrawn.Histological and immunohistochemical features of the tumor were consistent with ChRCC.One year after allograft nephrectomy,low doses of tacrolimus and MMF were administered for preventing allosensitization.Two years after allograft nephrectomy,the patient underwent kidney re-transplantation.Graft function remained stable with no ChRCC recurrence in more than 2-years of follow-up.CONCLUSION De novo ChRCC in kidney graft generally has a good prognosis after graft nephrectomy and withdrawal of immunosuppression.Kidney re-transplantation could be a viable treatment.A 2-year malignancy-free period may be sufficient time before re-transplantation.

Differentiate Xp11.2 Translocation Renal Cell Carcinoma from Computed Tomography Images and Clinical Data with ResNet-18 CNN and XGBoost

This study aims to apply ResNet-18 convolutional neural network(CNN)and XGBoost to preoperative computed tomography(CT)images and clinical data for distinguishing Xp11.2 translocation renal cell carcinoma(Xp11.2 tRCC)from common subtypes of renal cell carcinoma(RCC)in order to provide patients with individualized treatment plans.Data from45 patients with Xp11.2 tRCC fromJanuary 2007 to December 2021 are collected.Clear cell RCC(ccRCC),papillary RCC(pRCC),or chromophobe RCC(chRCC)can be detected from each patient.CT images are acquired in the following three phases:unenhanced,corticomedullary,and nephrographic.A unified framework is proposed for the classification of renal masses.In this framework,ResNet-18 CNN is employed to classify renal cancers with CT images,while XGBoost is adopted with clinical data.Experiments demonstrate that,if applying ResNet-18 CNN or XGBoost singly,the latter outperforms the former,while the framework integrating both technologies performs similarly or better than urologists.Especially,the possibility of misclassifying Xp11.2 tRCC,pRCC,and chRCC as ccRCC by the proposed framework is much lower than urologists.

Review of renal cell carcinoma and its common subtypes in radiology

Representing 2%-3% of adult cancers, renal cell carcinoma(RCC) accounts for 90% of renal malignancies and is the most lethal neoplasm of the urologic system. Over the last 65 years, the incidence of RCC has increased at a rate of 2% per year. The increased incidence is at least partly due to improved tumor detection secondary to greater availability of high-resolution cross-sectional imaging modalities over the last few decades. Most RCCs are asymptomatic at discovery and are detected as unexpected findings on imaging performed for unrelated clinical indications. The 2004 World Health Organization Classification of adult renal tumors stratifies RCC into several distinct histologic subtypes of which clear cell, papillary and chromophobe tumors account for 70%, 10%-15%, and 5%, respectively. Knowledge of the RCC subtype is important because the various subtypes are associated with different biologic behavior, prognosis and treatment options. Furthermore, the common RCC subtypes can often be discriminated non-invasively based on gross morphologic imaging appearances, signal intensity on T2-weighted magnetic resonance images, and the degree of tumor enhancement on dynamic contrast-enhanced computed tomography or magnetic resonance imaging examinations. In this article, we review the incidence and survival data, risk factors, clinical and biochemical findings, imaging findings, staging, differential diagnosis, management options and posttreatment follow-up of RCC, with attention focused on the common subtypes.

Comparative study of helical CT with contrast-enhanced ultrasound of renal carcinoma

Objective: To investigate the efficiency of helical CT comparing with contrast-enhanced ultrasound, and to im- prove the diagnosis efficiency of renal cell carcinoma (RCC). Methods: Thirty RCCs confirmed pathologically were studied retrospectively. The un-enhanced CT scan and the triphasic enhanced helical CT scan were performed in all cases, the gray-scale US and angiosonography with SonoVue were performed in all cases meantime. Results: 22 cases (73.3%) were diagnosed correctly by helical CT alone before operation. 7 cases (23.3%) were suspected as RCC with helical CT. One case (3.3%) was misdiagnosed with helical CT. 25 cases (83.3%) were diagnosed correctly with contrast-enhanced ultrasound alone pre-operation. One case (3.3%) was suspected as RCC with angiosonography. Four cases (13.3%) were misdiagnosed with angiosonography alone. 29 cases (96.7%) were diagnosed correctly by helical CT combining with angiosonography before operation, one case (3.3%) was diagnosed as renal mass with both helical CT and angiosonography. Conclusion: Contrast-enhanced ultrasound is sensitive in detecting blood flow, it can detect the enhancement of the tumor which cannot be detected by helical CT. CT and angiosonography have strong complement each other in the diagnosis of RCC.

Differentiation of Renal Oncocytoma and Renal Clear Cell Carcinoma Using Relative CT Enhancement Ratio

Background：The difference between renal oncocytomas （RO） and renal clear cell carcinomas （RCCs） presents the greatest diagnostic challenge.The aim of this study was to retrospectively determine ifRO and RCCs could be differentiated on computed tomography （CT） images on the basis of their enhancement patterns with a new enhancement correcting method.Methods：Forty-six patients with a solitary renal mass who underwent total or partial nephrectomy were included in this study.Fourteen of those were RO and 32 were RCCs.All patients were examined with contrast-enhanced CT.The pattern and degree of enhancement were evaluated.We selected the area that demonstrated the greatest degree of enhancement of the renal lesion in the corticomedullary nephrographic and excretory phase images.Regions of interest （ROI） were also placed in adjacent normal renal cortex for normalization.We used the values of the normal renal cortex that were measured at the same time as divisors.The ratios of lesion-to-renal cortex enhancement were calculated for all three phases.The Student＆#39;s t-test and Pearson＆#39;s Chi-square test were used for statistical analyses.Results：All RCCs masses showed contrast that appeared to be better enhanced than RO on all contrast-enhanced phases of CT imaging,but there was no significant difference in absolute attenuation values between these two diseases （P 〉 0.05）.The ratio of lesion-to-cortex attenuation in the corticomedullary phase showed significantly different values between RO and RCCs.The degree of contrast enhancement in RCCs was equal to or greater than that of the normal renal cortex,but it was less than that of the normal cortex in RO in the corticomedullary phase.The ratio of lesion-to-cortex attenuation in the corticomedullary phase was higher than the cut off value of 1.0 in most RCCs （84%,27/32） and lower than 1.0 in most RO （93%,13/14） （P 〈 0.05）.In the nephrographic phase,the ratio of lesion-to-cortex attenuation was higher than that in the corticomedullary phase in most RO （71%,10/14）,showing a prolonged enhancement pattern; and was lower than that in most RCCs （97%,31/32）,showing an early washout pattern （P 〈 0.05）.In the differentiation of RO from RCCs,the sensitivity was 93%,specificity 84%,positive predictive value 72%,negative predictive value 84%,and accuracy for RO was 87,if the ratio of lesion-to-cortex attenuation in a cortex phase was lower than the cutoff value of 1.0.The sensitivity was 71%,specificity was 97%,positive predictive value was 91%,negative predictive value was 91%,and accuracy for RO was 89%,if the ratio of lesion-to-cortex attenuation in nephrographic phase was higher than that in the corticomedullary phase.Conclusions：The ratios of renal lesion-to-cortex attenuation ratios may be helpful in differentiating RO from RCCs.

Contrast enhanced ultrasound of renal masses

Contrast enhanced ultrasound(CEUS) has gained clinical importance over the last years for the characterization of hepatic masses.Its role in extrahepatic indications has been investigated repeatedly but has been less comprehensively studied.Currently more than 50% of renal masses are incidentally diagnosed,mostly by B-mode ultrasound.The method of choice for characterization of renal lesions is contrast enhanced computed tomography(CECT).In the case of cystic lesions CECT refers to the Bosniak classification for cystic lesions to assess the risk of malignant behavior.The majority of masses are renal cell carcinoma,but the exact proportion is controversial.Disadvantages of CECT are a significant risk for patients with impaired renal function,allergic reactions and hyperthyroidism due to iodinated contrast agents.Several studies concerning CEUS for the characterization of both solid and cystic renal lesions have been published,but prospective multicenter studies are missing,the presented data being mainly descriptive.The aim of the this manuscript is to review the current literature for CEUS in renal masses,to summarize the available data and focus on possible concepts for studies in the future.

Chromophobe renal cell carcinoma： clinicopathologic features and outcomes of 16 cases

Chromophobe renal cell carcinoma （CRCC） is a distinctive, but not rare, malignant renal neoplasm.Series studies have revealed that the incidence of CRCC is between 3.6% and 10.4% of all kidney neoplasms. In China, the first CRCC case was described by our hospital in 1998; there have since been only a few case reports of CRCC in China and very few instances of long-term follow-up. To our knowledge, there is little information available regarding the clinical outcomes of patients with CRCC. In order to analyze the clinical and pathologic characteristics of CRCC and the prognosis in Chinese patients, we reviewed retrospectively the clinical data from cases of CRCC treated recently in our hospital.

Multidetector computed tomography features of pancreatic metastases from leiomyosarcoma: Experience at a tertiary cancer center

AIM: To describe the multidetector computed tomography features of pancreatic metastasis from leiomyosarcoma(LMS).METHODS: Between January 1995 and December 2012, 13 consecutive patients(11 women, 2 men; mean age of 57 years; range, 38-78 years) with pancreatic metastases from LMS were included in our study. Imaging features including location, number, largest dimension, tumor attenuation and enhancement characteristics, presence of necrosis, pancreatic ductal dilatation, common bile duct(CBD) dilatation, presence of pancreatitis, and atrophy were documented.RESULTS: The most common site of origin of the pancreatic metastases from LMS was uterus(38.5%), followed by retroperitoneum(30.8%) and extremity(23.1%). None of the patients in our study had pancreas as the first site of metastasis. All patients developed pancreatic metastases at a median interval of 24 mo. Pancreatic metastases from LMS were solitary in 8/13 patients and multiple in 5/13 patients, had no predilection for any part of the pancreas, were hypovascular on arterial phase in 10/13 patients and associated with pancreatic duct dilatation in 3/13 patients. None had CBD dilatation. None of the pancreatic metastases in LMS cohort caused pancreatitis, and atrophy. Median duration of follow-up was 19 mo for LMS cohort during which two patients underwent resection of metastasis(median survival 45 mo) while the remaining underwent systemic therapy(median survival 13 mo).CONCLUSION: Pancreatic metastases from LMS are often solitary and hypovascular masses and less commonly associated with pancreatic ductal dilatation, CBD dilatation, pancreatitis or pancreatic atrophy. Surgical resection of solitary LMS pancreatic metastasis can be considered due to the long survival of these patients.

The value of sestamibi single-photon emission computed tomography/computed tomography in differentiating and staging renal cell carcinomas:A systematic review

Misdiagnosis of benign renal neoplasms can lead to unnecessary surgical resections,which increases the risk of other morbid and mortality.Therefore,it is crucial to find a diagnostic modality for differentiation between benign and malignant renal masses.In the current study,we summarized published pieces of evidence concerning the use of technetium-99m(^(99m)Tc)-sestamibi single-photon emission computed tomography/computed tomography(SPECT/CT)as a promising diagnostic nuclear imaging modality for the differentiation of renal neoplasms.The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement for Systematic Reviews and Meta-Analyses.We conducted a systematic electronic database search for suitable studies from inception till February 20,2020 in 9 databases.The risk of bias was assessed for the included studies using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.We identified 9373 records after exclusion of 8978 duplicates using EndNote software.Title and abstract screening resulted in 761 records for further full-text screening.Finally,four studies were included with total sample size of 80 patients.The overall risk of bias was low to moderate.The results of all the included studies supported using^(99m)Tc-sestamibi SPECT/CT for the differentiation between benign and malignant renal neoplasms.The use of^(99m)Tc-sestamibi SPECT/CT could be a rapid,less invasive,promising diagnostic modality for histological diagnosis and staging of renal neoplasm,as well as monitoring post-therapy tumor's response.However,more studies with large sample sizes are essential to confirm the reliability and accuracy of this modality for usage.

Fat Poor Renal Angiomyolipoma Showing Collapsed Shape: A Case Report

Fat-poor renal angiomyolipoma (fpAML) and renal cell carcinoma (RCC) are difficult to differentiate and misdiagnosis can lead to unnecessary nephrectomy. We experienced a case showing a “collapsed shape” which reflected a fpAML tissue type. A renal tumor was incidentally discovered in a 42-year-old female during an abdominal ultrasound. RCC was suspected according to CT and MRI imaging results, and a partial nephrectomy was performed. However, the pathologic diagnosis was fpAML. Upon reevaluation of preoperative images, morphological change to the tumor due to contact with surrounding tissues: the collapsed shape was observed and could be identified by CT, which is the gold standard test for differentiating renal tumors. In cases where the collapsed shape is observed in a renal tumor, fpAML should be considered.

青年(18~40岁)非透明细胞型肾恶性肿瘤患者的临床病理特点及预后

目的分析总结单中心青年(18~40岁)非透明细胞型肾恶性肿瘤手术患者的临床、病理特征及预后,为同类患者的诊治提供参考。方法回顾性分析2012年1月—2022年8月于北京大学第三医院泌尿外科收治的113例青年非透明细胞型肾恶性肿瘤手术患者的病例资料,其中男性57例(50.4%),女性56例(49.6%);平均发病年龄(31.6±5.8)岁;左侧57例(50.4%)、右侧56例(49.6%)。青年肾恶性肿瘤手术患者约占同期所有年龄段肾恶性肿瘤手术患者总数的12.4%,其中青年非透明细胞型肾恶性肿瘤手术患者占同期青年肾恶性肿瘤手术患者总数的34.8%。结果102例(90.3%)患者行微创手术(腹腔镜或机器人辅助),另外11例(9.7%)行开放手术;肾部分切除术55例(48.7%),根治性肾切除术58例(51.3%),肾癌瘤栓患者11例(9.7%)。手术均顺利完成,围手术期无严重并发症发生。病理类型包括肾嫌色细胞癌32例(28.3%)、MiT家族易位性肾细胞癌25例(22.1%)、乳头状肾细胞癌20例(17.7%)、3种病理亚型合计占总体的68.1%。术后随访46(2~115)个月,8例(7.8%,8/102)出现肿瘤转移,2例死亡。结论青年非透明细胞型肾恶性肿瘤相对少见,病理类型以嫌色细胞癌为主,微创手术仍是该类肾恶性肿瘤患者的主要治疗方式,多数病理类型远期预后较好,合并瘤栓患者转移风险高、预后较差。

MSCT对乏脂肾血管平滑肌脂肪瘤与非透明细胞肾癌的鉴别诊断

目的分析乏脂肾血管平滑肌脂肪瘤(乏脂AML)与非透明细胞肾癌(肾乳头状细胞癌、嫌色细胞癌)的CT特征,提高病变的鉴别诊断效能。方法回顾性分析经手术病理证实乏脂AML19例、肾乳头状细胞癌(PRCC)16例及肾嫌色细胞癌(ChRCC)22例。测量肿瘤四期(平扫期、皮髓质期、实质期及排泄期)相同ROI的CT值及健侧肾皮质CT值,计算肿瘤强化百分比、多期相净增值、相对强化比并进行统计学分析。结果乏脂AML在平扫期及皮髓质期CT值高于PRCC与ChRCC的CT值,差异均有统计学意义(均P<0.05),在实质期及排泄期,乏脂AML与两者比较差异无统计学意义(均P>0.05)。乏脂AML在皮髓质期、实质期和排泄期的强化百分比高于PRCC、ChRCC,差异均有统计学意义(均P<0.05)。乏脂AML与PRCC、ChRCC在皮髓质期及实质期多期相净增值、相对强化比的差异均有统计学意义(均P<0.05),在排泄期差异无统计学意义(P>0.05)。结论乏脂AML与非透明细胞癌平扫及增强扫描有其特征性CT表现,强化百分比、多期相净增值、相对强化比可进一步提高AML与非透明细胞肾癌的诊断及鉴别诊断能力。

低级别嗜酸性肾肿瘤3例报告并文献复习

目的总结3例低级别嗜酸性肾肿瘤(LOT)患者的临床信息、影像学表现、病理表现及预后,提高临床对该疾病的认识。方法回顾性分析北京大学第三医院2020年2月—2022年9月收治的3例LOT患者的临床资料、影像学表现、病理资料及术后随访情况。结果3例确诊为LOT的患者均为男性,年龄51~70岁,肿瘤最大径14~21 mm,均为单发。患者均无特殊临床表现,计算机断层扫描示类圆形等密度影。3例患者均行保留肾单位的肿瘤切除术。大体标本的切面为棕黄色或棕色,肿瘤呈实性或部分区域囊实性。HE染色可见细胞质呈均匀的嗜酸性,细胞核呈圆形或椭圆形,局部可能有细微的核周空晕。免疫组化示CK7(+)、CD117(-)。病例2行基因检测提示可能具有临床意义的体细胞变异1个(结节性硬化症2基因)。术后随访时间12~23个月,随访期间肿瘤均未复发。结论LOT在临床症状与影像学上无明显特征,在组织形态学上表现出与肾嗜酸细胞瘤和肾嫌色细胞癌杂合性或交界性的特征,生物学行为呈惰性表现,行保留肾单位的肿瘤切除术,患者预后良好。