The angiographic appearance of renal angiomyolipoma and problems of its preoperative diagnosis

The radiodiagnostic difficulties of renal hamartoma (renal angiomyolipoma) have been discussed in connection with the authors' two cases. In the first case a unifocal cystic renal angiomyolipoma without tuberous sclerosis caused retroperitoneal haematoma and acute symptoms. In the second case a preoperative tentative diagnosis of angiomyolipoma was made, however, the Pringle-type dermal lesions were only observed 6 months after surgery on control examination. The authors state that the radiographic functional findings vary depending on the tissue structure of the tumour. Differential diagnosis of cystic angiomyolipoma containing little fatty and angiomatous tissue is impossible, whereas for the hypervascular variant a tentative diagnosis can be established even in the case of unifocal hamartoma.     

Variants of renal angiomyolipoma closely simulating renal cell carcinoma: difficulties in the histological diagnosis

Renal angiomyolipoma is considered to be a benign renal tumor composed of atypical blood vessels, smooth muscles and fat cells. We report 2 cases of unilateral renal angiomyolipoma. In both cases, our preoperative diagnosis was renal cell carcinoma, because no low density area compatible with fat tissue was noted in the tumors on radiographic evaluation. Through histological examination, both tumors proved to be angiomyolipomas mainly composed of epithelioid cells in 1 case, and spindle-shaped smooth muscle cells mimicking a leiomyoma in the other case. Both patients are well showing no evidence of metastases 16 and 14 months after nephrectomy, respectively.     

MSCT对肾血管平滑肌脂肪瘤的诊断价值

目的：探讨多层螺旋CT（MSCT）在肾血管平滑肌脂肪瘤诊断中的价值。方法：对手术证实的38例肾血管平滑肌脂肪瘤的术前多层螺旋CT资料进行回顾性分析,并在工作站行MPR、MIP图像重建,分析肾血管平滑肌脂肪瘤的MSCT表现,并与手术病理结果对照。结果：38例肾血管平滑肌脂肪瘤中,CT诊断血管平滑肌脂肪瘤的病灶被手术病理证实正确诊断的有32例,另外6例被病理证实为上皮样血管平滑肌脂肪瘤的病灶,其中3例CT误诊为肾癌,后期的3例被正确诊断。总诊断准确率达92.1%（35/38）。32例的血管平滑肌脂肪瘤CT平扫呈等、低、高低混杂密度的,其中31例显示有脂肪密度,多期增强扫描该31例皮质期肿块呈均匀或不均匀强化,但低于肾皮髓质强化,脂肪、坏死囊变、出血区无强化,分泌期肿块持续强化;1例整个病灶显示为高密度出血灶,多期增强扫描无明显异常强化;6例上皮样血管平滑肌脂肪瘤CT平扫呈均匀等密度,多期增强扫描显示皮质期明显强化,分泌期强化减弱。MIP显示其中31例血管平滑肌脂肪瘤的肿内迂曲、增粗的血管,其中1例无明显增粗迂曲血管影;6例上皮样血管平滑肌脂肪瘤内显示细小血管。结论：多层螺旋CT及多期增强扫描能对术前正确诊断肾血管平滑肌脂肪瘤有重要价值,但对上皮样血管平滑肌脂肪瘤的诊断尚需结合临床和实验室检查,甚至需要穿刺活检。     

转移性恶性肾血管平滑肌脂肪瘤三例报告

目的 探讨转移性恶性肾血管平滑肌脂肪瘤(AML)的诊断和治疗. 方法转移性恶性AML患者3例.男1例,女2例.年龄分别为36、55和37岁.主诉为持续性患侧腰痛1～6个月.2例B超、CT检查发现患肾实性占位.1例B超见肾肿块内不均匀高回声光团,CT测得脂肪负值信号.2例行根治性肾切除术,1例行肾切除术.3例均未放化疗. 结果 肿块切面灰红、灰黄,质软.病理镜下观察:2例瘤细胞呈上皮样,核有异型,伴坏死;1例大多区域为梭形平滑肌,脂肪细胞和血管混杂生长,部分区域细胞呈上皮样.免疫组化结果 均为VM(+),HMIM5(+),Melan-A(+),S-100(-),CK(-).3例病理诊断均为恶性肾AML,2例为上皮样型,1例为经典型、部分上皮样型.1例术后7年出现肺转移,行肺叶切除加清扫,随访12年无瘤生存.1例术后6年复发,行肿块切除术;术后lO年发现肝、后腹膜转移,再行肿块部分切除,随访12年带瘤生存.1例术后4个月出现肝、后腹膜转移,行肿块部分切除,3个月后失访. 结论 恶性肾AML罕见,诊断依靠病理和免疫组化检查.治疗方法无特殊.     

Angiomyolipoma of the kidney: report of three cases and a statistical study of 194 cases in Japan

Three cases of renal angiomyolipoma are reported. The first case was a 53-year-old female with the complaint of left flank pain. In both cases selective angiography revealed a renal tumor, and computerized tomography disclosed a renal mass with low density corresponding to the fat tissue. From several examinations these two cases were preoperatively diagnosed as renal angiomyolipoma and nephrectomy was performed. Histopathological diagnosis was renal angiomyolipoma. The third case was a 64-year-old female with the complaints of left flank pain and macrohematuria. In this case computerized tomography revealed a renal mass which did not have a low density area. The possibility of renal cell carcinoma was considered and nephrectomy was performed. Histological diagnosis was renal angiomyolipoma which was primarily composed of smooth muscle cells. The first case had a calcified lesion in the brain. But there was no evidence of tuberous sclerosis in the following two cases. Some problems in diagnosis and treatment of renal angiomyolipoma are presented, and a statistical study is made on 194 reported cases of renal angiomyolipoma in Japan.     

肾血管平滑肌脂肪瘤自发破裂出血的急诊处理(附24例报告)

目的 探讨肾血管平滑肌脂肪瘤自发破裂出血的急诊处理.方法 对24例肾血管平滑肌脂肪瘤自发破裂出血患者的临床资料及随访结果进行回顾性分析.术前均行B超和CT检查,22例诊断为肾血管平滑肌脂肪瘤自发破裂出血,2例未能排除肾癌出血.3例保守治疗,4例行选择性肾动脉栓塞术,17例急诊手术.结果 3例保守治疗患者中1例病情稳定,2例改行手术治疗.4例行肾动脉栓塞术患者栓塞成功,出血停止.4例行肾切除术,13例行保留肾单位手术,其中5例行后腹腔镜手术.术后病理诊断为肾血管平滑肌脂肪瘤并出血.随访3个月～6年,肿瘤无复发或转移.结论 B超和CT是诊断肾血管平滑肌脂肪瘤出血的重要手段.治疗可以选择保守治疗、肾动脉栓塞或者急诊手术.     

开放性冷循环射频消融治疗近肾门处肾错构瘤的临床疗效

目的：探讨开放性冷循环射频消融治疗近肾门处错构瘤的可行性及临床疗效。方法：对4例近肾门处错构瘤患者实施开放性错构瘤切除,肿瘤基地部行冷循环射频消融治疗。肿瘤位于左肾l例,右肾3例。肿瘤最大径5～8．5cm。术后采用CT、超声造影定期随访。结果：平均手术时间（95i20）min,平均出血量（100±28）ml,术中均未输血。术后疼痛3例,术后均有发热,体温（39．0±0．5）℃。术后6周,4个病灶均完全消融。术后有1例患者血红蛋白降低明显但未输血,术后血肌酐、红细胞沉降率较术前无明显变化;肿瘤较大者术后短期内肾小球滤过率减低。4例患者获得3个月后CT复查,4例病灶完全消融,随访时间2～18个月,未见肿瘤复发。结论：冷循环射频消融是一种安全有效的治疗新方法;采用开放性射频消融保留肾单位手术治疗近肾门处肾错构瘤是一种可供选择的方法,临床效果比较理想。     

Congenital seminal vesicle cyst and coexisting renal agenesis: laparoscopic approach

The diagnosis of angiomyolipoma can typically be made on the basis of characteristic computed tomography findings. Varying tissue compositions within an angiomyolipoma can create difficulty in pathologically differentiating benign from malignant lesions. Epithelioid angiomyolipoma is a variant of angiomyolipoma characterized by the presence of epithelioid cells. We report a case of two discrete contrast-enhancing lesions within an enlarging angiomyolipoma that radiographically mimicked malignant elements. This finding presented a diagnostic challenge in terms of selecting medical versus surgical intervention. Surgical excision of the lesions was performed and the pathologic examination revealed a benign angiomyolipoma with epithelioid features.     

肝脏血管平滑肌脂肪瘤的诊断与治疗八例报告

目的 为提高对肝脏血管平滑肌脂肪瘤（angiomyolipoma,AML)的认识,作出正确诊断和治疗。方法 回顾分析8例肝AML的临床表现、影像学表现、病理学检查及外科治疗。结果 8例中术前做出正确诊断者仅1例,其中4例误诊为恶性肿瘤,8例均获得手术切除,术后恢复良好。结论 肝AML有其临床特点,CT或MRI亦具特异性。目前AML在术前常难做出正确诊断,与发病少、缺乏认识及影像学表现多样性有关。该病手术治疗效果好。     

A case of pararenal angiomyolipoma arising from an existing exophytic angiomyolipoma

A 52-year-old healthy woman with a congenital solitary right kidney presented with an incidentally found pararenal mass. Computed tomography and magnetic resonance imaging revealed an exophytic mass in the right kidney consistent with an angiomyolipoma and an additional enhancing pararenal mass that contained fatty elements. Differential diagnosis of the mass included liposarcoma and angiomyolipoma. Upon exploration, the exophytic angiomyolipoma was found to be contiguous with the pararenal mass via an isthmus of fatty tissue. Frozen sections were taken from both masses which confirmed that both were angiomyolipoma. This is the first case reported in the literature wherein an angiomyolipoma extended extrarenally and formed a significantly larger pararenal mass.     

Renal angiomyolipoma with malignant transformation, simultaneous occurrence with malignity and other complex clinical situations

Renal angiomyolipoma is a benign kidney tumor, which is characterized by the presence of mature or immature fat tissue, thick-walled blood vessels, and smooth muscles. However, there is a rare possibility of transformation to a malignancy. This transformation could be toward sarcoma. And also angiomyolipoma could be associated with renal adenocarcinoma in the same kidney. The aim of this study is to show the association of angiomyolipoma with complex clinical situations such as malign transformation, simultaneous occurrence with adenocarcinoma, bilateral tumors with tuberous sclerosis or Wunderlich Syndrome. Findings of clinical presentation, pathological evaluation, urography, ultrasonography, and computerized tomography of 19 patients who were diagnosed angiomyolipoma in our clinic during 1994–2003 were examined retrospectively. Our records indicated that radical nephrectomy was performed in three cases of angiomyolipoma in which the differential diagnosis from adenocarcinoma could not be made and in another case of angiomyolipoma, which was associated with adenocarcinoma. Simple nephrectomy was performed in four symptomatic angiomyolipoma cases with tumor size larger than 4 cm and partial nephrectomy in another case. In one case, renal angiomyolipoma was associated with adenocarcinoma in the same kidney. In one case, post-operative recurrence of angiomyolipoma developed 7 months after nephrectomy. This patient was diagnosed low-grade leiomyosarcoma. Angiomyolipoma is regarded as a benign tumor of the kidney; however, it may also show aggressive behaviors and rarely transform to sarcoma. It may also exist in the same kidney along with adenocarcinoma or sarcoma.     

肾上皮样血管平滑肌脂肪瘤诊治探讨

目的 提高肾上皮样血管平滑肌脂肪瘤(EAML)的诊治水平.方法 肾EAML患者5例.男3例,女2例.平均年龄46(26～64)岁.患侧腰部胀痛3例,体检偶然发现2例.肿瘤直径2.9～10.1 cm.B超和CT检查诊断为血管平滑肌脂肪瘤2例,肾癌、肾上腺肿瘤、肝癌各1例.行肾肿瘤剜除术3例,肾楔形切除术1例,肾切除术1例.结果 病理报告:肿瘤由不同比例的异常厚壁血管、平滑肌和脂肪组织构成.上皮样细胞胞质浓密嗜酸性或透亮,有嗜酸性颗粒,并有丰富的血管,上皮样细胞簇常围绕血管.组织学形态表现为圆形、多边形和梭形上皮样细胞灶性分布于脂肪瘤中,上皮样瘤细胞免疫组化标记SMA、Vimentin、HMB45表达阳性.5例病理诊断均为肾EAML.随访2～12个月,未见局部复发及远处转移.结果 肾EAML由厚壁血管、脂肪和平滑肌细胞混合组成,上皮样细胞簇常围绕血管.确诊依赖于临床、影像学及病理学检查相结合,免疫组织化学染色有助于诊断及鉴别诊断.早期诊断及完整切除肿瘤是治疗关键.     

Rapidly growing renal angiomyolipoma during pregnancy with tumor thrombus into the inferior vena cava: a case report

A case of renal angiomyolipoma rapidly growing during pregnancy with tumor thrombus into the inferior vena cava is reported. Angiomyolipoma in a 31-year-old woman was incidentally found by ultrasonography. CT scan revealed a fat-containing tumor in the right kidney with 4 cm in diameter. The patient was followed at outpatient clinic without any treatment. Fifteen months later, the post-delivery follow-up CT scan showed that tumor size had grown up to 11 cm in diameter. Although laparoscopic right nephrectomy was tried, open transperitoneal right nephrectomy was performed because the tumor thrombus extending into the inferior vena cava was found during the laparoscopic procedure. Pathological diagnosis was angiomyolipoma of the kidney. There are several reports that indicate angiomyolipoma grows rapidly during pregnancy. Our case demonstrates that careful follow-up is required for angiomyolipoma in women with possible conception and delivery.     

Malignant transformation of renal angiomyolipoma: a case report

We report a case of renal angiomyolipoma (AML) with malignant transformation. A 28-year-old woman developed large bilateral renal masses 5 months before admission to our hospital. She was diagnosed with tuberous sclerosis when she was 4 years old. Total nephrectomy of the left kidney was performed, but she died during the operation. Although the focal region of the resected tumor had the appearance of a classic AML, most of the lesion showed a diffuse proliferation of atypical epithelioid cells resembling that in renal cell carcinoma. The epithelioid cells had extremely pleomorphic and hyperchromatic nuclei with frequent mitotic figures, including atypical forms. Immunohistochemical analysis revealed that the atypical epithelioid cells and the typical AML lesions were both positive for HMB-45 but that the former were negative for epithelial and myogenic markers. The smooth muscle cells and thick-walled vessels were focally positive for muscle-specific actins. Furthermore, the atypical epithelioid cells were immunoreactive for p53, whereas the foci of the typical AML were negative. Examination of the microdissected paraffin-embedded tissues revealed p53 mutations in the malignant epithelioid areas in AML but not in the renal parenchyma or typical AML areas. In this case it is proposed that p53 mutation may play an important role in malignant transformation of renal AML.     

肾血管平滑肌脂肪瘤自发性破裂(附23例报告)

目的 探讨肾血管平滑肌脂肪瘤(RAML)自发性破裂的临床表现、诊断和治疗。方法 肾血管平滑肌脂肪瘤自发破裂23例，临床表现突发腰腹疼痛者21例，腰部酸胀者2例；其中伴血尿3例、恶心呕吐2例、休克3例、发热1例。23例B超检查，确诊13例；CT检查21例，确诊16例。结果 术前确诊RAML者16例，术中冰冻切片确诊2例，误诊为肾癌者4例、肾感染性病变者1例。行肾切除10例，肾部分切除和肿瘤剜除术各6例，数字减影血管造影(DSA)加栓塞术1例。结论 RAML自发性破裂后常改变临床症状和影像学特征，导致误诊和肾切除，综合分析临床表现和影像学资料可以提高术前确诊率，术中冰冻切片可以避免不必要的肾切除。     

Malignant-like angiomyolipoma of the liver: report of one case and review of the literature

Frequently found in kidney, angiomyolipoma is a rare mesenchymal tumor when diagnosed in the liver and usually benign composed of proliferative blood vessels, fatty tissue and smooth muscle. We report the case of a 67-year-old woman who underwent a left hepatectomy for a 4th segment tumor unidentified after imaging and fine needle biopsy. Final anatomopathologic examination revealed an epithelio?d hepatic angiomyolipoma with signs of malignant behaviour as vascular and lymphatics embolus and invaded left portal vein thrombosis. During the subsequent 24-month follow-up, no recurrence was observed. A review of the literature found only two cases of malignant hepatic angiomyolipoma with fatal issue, however, their incidence must be underrated because of their scarcity and the difficulty of their diagnosis, which needs immunohistochemical confirmation with HMB 45 in particularly. Advances in imaging and anatomopathology in particular with the concept of PEComa (Perivascular-Epithelio?d Cell) as the unifying feature should lead to the recognition of the various variant patterns and cell types. The latter which are important for a correct diagnosis, in order to obtain reliable data about frequency, possible malignant behaviour and therefore consensus management for hepatic angiomyolipoma.     

Renal replacement lipomatosis

We report a relatively rare case of renal replacement lipomatosis presenting as a renal mass. Computed tomography revealed a predominantly low-density and roundish mass, with an irregular renal parenchyma, high-density calcification, and abundant low-density fat. The differential diagnosis before surgery was squamous cell carcinoma, teratoma, or angiomyolipoma of the kidney. The case was initially misdiagnosed, because we had no experience with this disease. After mass exploration, histological examination confirmed the diagnosis of renal replacement lipomatosis. The patient was free from signs of recurrence 10 months after the operation.     

RENAL ANGIOMYOLIPOMA IN CHILDREN: DIAGNOSTIC DIFFICULTY IN 3 PATIENTS

Purpose

Because angiomyolipoma is less common in children than in adults, its diagnosis can be difficult. We present 3 cases of pediatric angiomyolipoma in which diagnostic problems resulted due to the presenting characteristics.

Materials and Methods

We report on 3 children with unilateral renal angiomyolipoma. Computerized tomography (CT) and ultrasonography revealed 3 large renal masses, 20, 7 and 8 cm. in diameter, respectively. A correct diagnosis was not made preoperatively in any case by CT, ultrasound or fine needle biopsy. Wilms tumor was suspected in the first patient who received preoperative chemotherapy. Imaging was inconclusive in the other 2 cases.

Results

All patients underwent surgical exploration and subsequent nephrectomy due to the large size of the tumor. At followup 33, 23 and 13 months postoperatively all children were well without signs of recurrence.

Conclusions

It has been reported that the demonstration of fat on renal ultrasound and CT can diagnose angiomyolipoma in 95% of the cases. Most radiologists rely solely on CT demonstration of lipid density in the renal mass to diagnose angiomyolipoma but the identification at imaging of lipid tissue may be difficult in small tumors. In our cases the fat content of the tumors was less than 10% despite the large size. This low fat content results in misdiagnosis, since fatty tissue is also present in other renal tumors, such as lipoma, liposarcoma, teratoma and Wilms tumors. We recommend conservative surgery when tumor size permits in pediatric patients with angiomyolipoma to avoid chemotherapy.     

Diagnosis and treatment of renal angiomyolipoma

We have hitherto reported 6 cases of renal angiomyolipoma. Recently, we encountered two more such cases. Case 1 is a 34-year-old woman with fever as the chief complaint. DIP revealed a tumor mass in the right upper pelvic pole. This mass showed a strong echo level on ECHO and adipose tissue of low density on CT scan. Therefore, the patient was diagnosed as having renal angiomyolipoma. Since liposarcoma was not ruled out by the examination of frozen sections during operation, nephrectomy was performed. Case 2 is a 40-year-old woman. Diagnosed as having bilateral renal angiomyolipoma, she underwent right nephrectomy 14 years ago. Two years ago, she had heavy hematuria, and had embolization of the left renal artery. She has had no bleeding since the embolization. We are of the view that ECHO and CT can are very useful for diagnosis of renal angiomyolipoma, and embolization for heavy hematuria, a complication, should be performed first of all.     

A case report of spontaneous rupture of renal cell carcinoma difficult to be distinguished from angiomyolipoma

A 56-year-old woman was admitted with right flank pain as the chief complaint without any trauma. Abdominal and chest computed tomography (CT scan) demonstrated with low-density area in a retroperitoneal hematoma suspected of spontaneous rupture of angiomyolipoma and hematothorax. Superselective transarterial embolization and drainage of the thoracic cavity were performed. Three months later a right renal tumor in perirenal hematoma was revealed by abdominal CT scan and suspected renal cell carcinoma. Right nephrectomy was performed. Histopathology revealed renal cell carcinoma. Including this case, 31 cases of spontaneous rupture of renal cell carcinoma have been reported in the Japanese literature.