Massive epithelioid angiomyolipoma of the kidney in a young girl

We report the case of a huge right renal tumor in a 17-year-old girl. Absence of fat on preoperative magnetic resonance imaging suggested renal cell carcinoma, and surgery was performed. Pathologic evaluation with HMB-45 immunohistochemical staining confirmed the diagnosis of epithelioid angiomyolipoma. The tumor consisted predominantly of epithelioid cells, and it could easily be misidentified as a renal cell carcinoma due to the paucity of the fat component. Previous reports have suggested that epithelioid angiomyolipomas have the potential to be malignant, and thus regular postoperative surveillance is recommended. Our patient had no signs of recurrence at her most recent follow up, 12 months after surgery.     

Epithelioid angiomyolipoma of the kidney

Epithelioid angiomyolipoma is a recently recognized variant of angiomyolipoma, which is characterized by the presence of polygonal cells with densely eosinophilic cytoplasm and varying degrees of nuclear atypia. Only a relatively small number of cases of epithelioid angiomyolipoma of the kidney have been reported in the literature. We report a case of epithelioid angiomyolipoma of the kidney that occurred in a 38-year-old woman. The tumor was composed of diffuse sheets of epithelioid cells, adipocytes and only scattered thick-walled blood vessels. The epithelioid cells had pleomorphic and hyperchromatic nuclei with densely eosinophilic cytoplasm. Hemorrhage, necrotic foci and clusters of foamy macrophages were present. HMB-45, CD117 (c-kit) and CD68 were detected in the epithelioid cells. There was no expression of cytokeratin, epithelial membrane antigen or desmin. The patient showed no evidence of recurrence or metastatic disease 9 months after nephrectomy.     

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.     

Monotypic epithelioid angiomyolipoma of the kidney: A case report

A case of monotypic variant of epithelioid angiomyolipoma (AML) observed in a 62-year old woman is reported. The patient complained of abdominal fullness caused by a huge left renal mass without evidence of tuberous sclerosis complex. Imaging studies showed a left renal mass with an area showing hemorrhage and necrosis. The left renal mass, spleen and pancreatic tail were removed en bloc transabdominally. The resected tumor weighed 1200 g and showed focal necrosis and hemorrhage. Microscopically, the tumor was composed exclusively of atypical polygonal cells with copious eosinophilic cytoplasm, pleomorphic nuclei and prominent nucleoli. Tumor cells were considered to derive from perivascular epithelioid cells, and exhibited strong positive staining for HMB-45 and c-KIT, but were negative for epithelial, smooth muscle, and neural markers. As this tumor had none of the typical elements of classic AML, the final pathological diagnosis was monotypic epithelioid AML.     

Malignant hepatic angiomyolipoma: report of a case and review of literature

Hepatic angiomyolipoma, a constituent of the group of tumors showing differentiation resembling perivascular epithelioid cells, is primarily appreciated in its benign form. Regardless of their location, this family of tumors is characterized by the presence of mature adipocytes, blood vessels, and spindle-epithelioid cells. These tumors also possess similar immunohistochemical profiles, including positivity for melanocytic (HMB-45) and smooth muscle (smooth muscle actin) markers. Here, we present a case of malignant hepatic perivascular epithelioid cells that was initially confined to the liver, treated by resection, and subsequently recurred within and metastasized beyond the liver. We take this opportunity to report the fourth case of malignant hepatic angiomyolipoma (HAML) and review the literature. We will discuss the features that aid in distinguishing between benign and malignant HAML, and their similarities. In summary, the common features of both benign and malignant HAML include the following: the 3 basic histologic components of AML, expression of melanocytic and smooth muscle markers, invasion into adjacent normal parenchyma, and cytologic atypia. The unique features of malignant HAML are as follows: clinical evidence of aggressive behavior such as metastasis or death owing to disease, coagulative necrosis, and loss of CD 117 expression.     

The use of the Ki-67 marker in the pathological diagnosis of the epithelioid variant of renal angiomyolipoma

Objective:  Epithelioid angiomyolipoma (EAML) is a rare malignant variant of renal angiomyolipoma (AML). There were 34 cases of EAML reported in 25 studies (including this present study) over the past decade. About 68% were females and 32% males. The mean age was 40.1 years, 53% developed metastatic disease after nephrectomy, and eight patients had TSC. All cases are reported positive when stained with HMB-45 which also labels all classical AML. This study evaluates the use of Ki-67 (proliferation marker) in the pathological diagnosis of EAML and distinction from classical AML. Method:  Immunohistochemical reactions for Ki-67 were generated on multiple representative blocks of tissue obtained from two cases of HMB-45 positive EAML and four cases of classic AML and the percentage of positively staining cells estimated. Results:  Both cases of EAML were strongly positive for Ki-67 while all four classic AML were completely negative. Conclusion:  The Ki67 is a useful marker in which distinguishes the malignant epithelioid variant of AML from classic AML.     

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.     

Renal epithelioid angiomyolipoma with malignant behavior

The patient was a 22-year-old woman with a history of tuberous sclerosis who complained of abdominal distention. Computed tomography showed bilateral renal masses with minimal fat tissue that were unlike classical angiomyolipoma (AML), as well as enlargement of the paraaortic lymph nodes, pleural effusion, and ascites, similar to other advanced malignant neoplasms such as renal cell carcinoma and renal sarcoma. We performed a left nephrectomy to relieve the symptoms. A pathological examination revealed that the tumor was composed of polygonal epithelioid cells positive for both αSMA and HMB-45, as well as spindle-shaped cells, while immunoreactivity proved the tumor to be an eAML, a subtype of AML with malignant potential. Although the patient was scheduled for postoperative adjuvant chemotherapy, her condition worsened and she died on postoperative day 24 before receiving chemotherapy. We discuss this case with reference to previous reports.     

Malignant transformation of renal angiomyolipoma

In the present paper, two cases of malignant transformation of renal angiomyolipoma without tuberous sclerosis are reported. Pathological examination revealed that, in both cases, in addition to the areas affected by typical angiomyolipoma, there were areas that contained elevated numbers of perivascular epithelioid cells with prominent nuclear pleomorphism. Immunohistochemical examination revealed that both cases were negative for keratin and epithelial membrane antigen, but were positive for the melanogenesis-related marker HMB-45. Metastatic diseases appeared 40 months after radical nephrectomy in the first case and 18 months in the second case.     

Role of mammalian target of rapamycin inhibitor in the treatment of metastatic epithelioid angiomyolipoma: A case report

Epithelioid angiomyolipoma has malignant potential; however, no effective therapy has been established for advanced cases. A 50‐year‐old woman with a history of right nephrectomy for epithelioid angiomyolipoma was referred to our institution. Computed tomography and magnetic resonance imaging showed multiple tumors in her lung, liver and pelvic cavity. The liver and pelvic tumor specimens obtained by needle biopsy confirmed the diagnosis of epithelioid angiomyolipoma recurrence. The patient was treated with everolimus (10 mg/day). Three months later, pulmonary lesions disappeared; liver and pelvic tumors significantly shrank in size, but the pelvic tumor gradually enlarged again. We carried out surgical resection of the residual liver and pelvic cavity tumors. Although the mammalian target of rapamycin inhibitor seems to be effective for treating epithelioid angiomyolipoma, its long‐term effects remain unknown. Thus, aggressive administration of a multidisciplinary treatment including molecular target therapy and surgical resection is required to improve the prognosis of epithelioid angiomyolipoma.     

Renal angiomyolipoma: a clinicopathologic, immunohistochemical, and follow-up study of 46 cases.

We reviewed 46 cases of renal angiomyolipoma covering the period from 1977 to 1997. Eight cases were associated with tuberous sclerosis and one with lymphangiomyomatosis. Histologically, the lesions were most often classic with the three usual components, i.e., mature adipose tissue, thick-walled blood vessels, and smooth muscle. Seven cases were particularly misleading: three cases were entirely adipose mimicking liposarcoma: two cases had an exclusively smooth-muscle component, one mimicking lymphangiomyomatosis and one with epithelioid cells; another case had a monophasic epithelioid pleomorphic component ("REON": renal epithelioid oxyphilic neoplasm) and proved to be fatal; and another case was associated with collecting duct carcinoma. The immunohistochemical profile showed the coexpression of alpha-smooth-muscle actin and HMB45. Our study is the first to show positivity of estrogen and progesteron receptors or both in more than 25% of cases. Of 35 cases with follow-up information, only one patient died of malignant spread of angiomyolipoma.     

Perivascular epithelioid cell tumor ('PEComa') of the uterus: a subset of HMB-45-positive epithelioid mesenchymal neoplasms with an uncertain relationship to pure smooth muscle tumors.

The family of lesions thought to be composed at least in part of perivascular epithelioid cells, characterized as HMB-45-positive epithelioid cells with clear to eosinophilic granular cytoplasm and a propensity for a perivascular distribution, includes some forms of angiomyolipoma and lymphangioleiomyomatosis, as well as clear cell "sugar" tumor (CC-SUGAR). When composed predominantly or exclusively of epithelioid cells, it has been suggested that these lesions be classified as "perivascular epithelioid cell tumors" (PEComa). Four cases of uterine PEComa have been described in the literature, three of which exhibited aggressive behavior. We report the clinical, histologic, and immunohistochemical features of eight more examples of uterine PEComa. Patients ranged in age from 40 to 75 years (mean 54 years). Most patients presented because of abnormal uterine bleeding, and grossly a mass was present in the uterine corpus. Morphologically, the tumors could be divided into two groups (A and B). Group A tumors demonstrated a tongue-like growth pattern similar to that seen in low-grade endometrial stromal sarcoma and were composed of cells that tended to have abundant clear to eosinophilic pale granular cytoplasm, diffuse HMB-45 expression, and focal muscle marker expression. Group B tumors were composed of epithelioid cells with less prominent clear cell features, smaller numbers of which were HMB-45-positive. They also featured extensive muscle marker expression and a lesser degree of the endometrial stromal sarcoma growth pattern seen in group A tumors. Two of the four patients with group B tumors had pelvic lymph nodes involved by lymphangioleiomyomatosis, and one of these patients had the tuberous sclerosis complex. Seven of the eight patients with PEComas were treated by hysterectomy. All eight patients are alive and well, although follow-up of >2 years was available only for two patients. Uterine epithelioid smooth muscle tumors and low-grade endometrial stromal sarcomas were compared with the PEComas. Group A PEComas, group B PEComas, and epithelioid smooth muscle tumors were all parts of a continuous histologic spectrum, with group A PEComa at one end of the spectrum and epithelioid smooth muscle tumors at the other, while group B tumors shared features of both. PEComa was histologically and immunohistochemically distinct from endometrial stromal sarcoma. Our data and a review of the literature indicate that PEComa is a subset of HMB-45-positive epithelioid mesenchymal tumors of the uterus with an uncertain relationship to pure smooth muscle tumors. Although none of the patients in this study experienced recurrence during a short follow-up period, some reported in the literature have had recurrences; consequently, we think uterine PEComa should be considered a tumor of uncertain malignant potential until long-term outcome data for a larger number of patients become available.     

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.     

Hepatic angiomyolipoma developing during the follow-up of ulcerative colitis: Report of a case and review of the literature

Hepatic angiomyolipoma is a rare tumor composed of spindle-shaped and epithelioid smooth muscle cells, adipose tissue, and proliferating blood vessels. We report the first documented case of this tumor developing in a patient with ulcerative colitis. A solitary tumor (7.5×7.5×7cm) was detected in the left lateral segment of the liver and a left hepatic lobectomy was performed. The diagnosis of angiomyolipoma was confirmed by a pathological examination. We also review the literature on previously reported cases of hepatic angiomyolipoma.     

Primary malignant melanoma of the anterior mediastinum in a child

Primary malignant melanoma of the mediastinum is extremely rare. We report a case not previously reported of primary malignant melanoma located in the mediastinum in a 11-year-old boy. The tumor could not be completely resected as a result of extensive invasion of the large blood vessels. Histologically, the tumor was heavily pigmented and composed of vague fascicles of spindle cells intermingled with epithelioid cells. Immunohistochemical analysis showed vimentin, S-100 protein, Melan-A, and HMB-45 immunoreactivity in most of the tumor cells. Nearly 50% of the tumor cells were also positive for p53. It is suggested that primary malignant melanoma of the anterior mediastinum may have a histogenetic relationship to the recently described aggregates of nevus cells in the thymus or mediastinal lymph nodes.     

PEComa in the rectum: A case report and review of the literature on epithelioid angiomyolipoma

Introduction and importancePerivascular epithelioid cell tumor (PEComa), especially angiomyolipoma (AML) is a rare mesenchymal tumor in wide array of anatomic locations such as the kidney, lung, uterus, and gastrointestinal tract. AML is commonly found in the kidneys and classified as a classic AML or epithelioid AML. We report a case of epithelioid AML diagnosed in the rectum, treated by robot assisted low anterior resection.Presentation of caseA 45-year-old woman was referred to our hospital because when an intramural rectal mass was detected on a colonoscopic examination performed during a regular health checkup. Colonoscopic examination revealed an intramural mass, 2 cm in diameter, bulging in the rectal wall, 6 cm from the anal verge. Based on abdominal and pelvic computed tomography images and magnetic resonance imaging findings, the patient was suspected of having gastrointestinal stromal tumor of the rectum. The patient was treated by robot assisted low anterior resection under the diagnosis of GIST. The patient improved without any postoperative complication and was diagnosed as epithelioid AML, a type of PEComa.DiscussionAML diagnosed in gastrointestinal tract is very rare and among them, epithelioid AML has possibility of malignancy. However, confirmed diagnosis before surgical resection is difficult because PEComa shows nonspecific imaging characteristics. Treatment of choice of epithelioid angiomyolipoma is surgical resection.ConclusionBecause epithelioid AML has the potential for malignancy, clinicians must be aware of the knowledge of the characteristics and natural history of epithelioid AML.     

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.     

Epithelioid angiomyolipoma : a case report

A 63-year-old woman with a right renal tumor diagnosed by ultrasound, consulted our hospital in October 2008. The findings of her physical examination were unremarkable. The results of urinalysis and other routine blood tests were normal. The urinary cytology was negative for malignant cells. Dynamic computed tomography showed a right renal mass (diameter, 7.5 cm), which was enhanced in the early phase and washed out in the late phase. We initially thought that the patient had renal cell carcinoma. Therefore, laparoscopic right nephrectomy was performed in October 2008. The tumor section was found to be encapsulated, and focal hemorrhage and necrosis were observed. Histological examination of the tumor by hematoxylin-eosin staining revealed that it contained polygonal cells, eosinophilic cytoplasm and large nuclei. Immunohistochemical staining of anticytokeratin antibodies AE1/AE3 and CAM5.2 (markers for renal cell carcinoma) was negative. However, immunohistochemical staining of HMB-45, a marker for melanoma, was positive. The patient was finally diagnosed with epithelioid angiomyolipoma. She did not show any evidence of tumor recurrence for 25 months after the surgery.