Angiomyolipoma of the bladder

Angiomyolipoma of the bladder is an extremely rare neoplasm. We report a case of a 55-year-old woman with an angiomyolipoma of the bladder visualized on pelvic sonogram as a 5 mm polyp in the floor of the bladder. The lesional tissue consisted of spindle cells, epithelioid cells, and adipocytes, with occasional thick-walled blood vessels. Immunohistochemical studies showed the spindle and epithelioid cells to be focally positive for HMB-45 and diffusely positive for actin and muscle cell antigen (HHF-35), which confirmed the diagnosis of angiomyolipoma. A review of the recent literature on the pathogenesis of angiomyolipoma follows.     

Angiomyolipoma of the anterior mediastinum

Angiomyolipoma is a benign tumor composed of varying proportions of smooth muscle cells, blood vessels, and adipose tissue that most commonly occurs in the kidney. Sporadic lesions and lesions arising in the setting of the tuberous sclerosis complex have been reported in extrarenal sites. We present the case of an incidentally discovered angiomyolipoma in the anterior mediastinum. Thymoma was suspected clinically, and the lesion was composed mainly of spindled-to-epithelioid cells arranged in a histologic pattern reminiscent of hemangiopericytoma, a pattern that has been described in thymoma. Immunohistochemical stains revealed positivity for smooth muscle actin and HMB-45, revealing the expression of smooth muscle and melanocytic markers characteristic of angiomyolipoma and other lesions in the PEComa family.     

Angiomyolipoma of the kidney--an immunohistochemical study

The study included 25 patients with angiomyolipoma of the kidney. None of them had any signs of tuberous sclerosis. Serious clinical complications such as massive hemorrhage (2/25) and hydronephrosis (2/25) were documented in four patients. Concomitant adenoma of the adrenal gland and renal cell carcinoma were found in one patient each. All tumors consisted of a differing mixture of mature adipose tissue, smooth muscle cells and blood vessels, with thickened walls devoid of elastic lamina. Immunohistochemically, the smooth muscle cells stained strongly with antibodies against vimentin, desmin and actin, as well as HMB-45 and NKI/C3. Immunohistochemical staining for NKI/C3 was stronger and more diffusely distributed. These two markers proved to be very useful in the diagnosis of angiomyolipoma, when only needle biopsy specimens are available.     

累及淋巴结的肾脏血管平滑肌脂肪瘤一例

患者男,33岁,乏力,低热1年,左侧腰部阵发性绞痛反复发作1个月于2002年4月5日入院,体检：无发热、发冷,夜间盗汗及尿频,尿急、尿痛、尿血等病史。B超,X线及CT检查均提示：左肾占位性病变,肾细胞癌可能性大。实验室检查无异常。专科检查：双肾区对称无隆起,左肾区叩击痛,左输尿管走行区轻度压痛,膀胱区隆起无压痛。临床诊断;左肾肿瘤。     

Angiomyolipoma of the Kidney with Lymph Node Involvement

A case of renal angiomyolipoma with regional lymph node involvement is added to 20 cases previously reported. This represents the 11th case reported in a non-tuberous sclerosis patient. The electron microscopic features of the tumor are discussed and correlated with the light microscopic findings.     

Angiomyolipoma of the kidney with lymph node involvement.

A case of renal angiomyolipoma with regional lymph node involvement is added to 20 cases previously reported. This represents the 11th case reported in a non-tuberous sclerosis patient. The electron microscopic features of the tumor are discussed and correlated with the light microscopic findings.     

Oncocytoma of the kidneys

Fourteen cases (4%) of renal oncocytoma have been detected in a retrospective and current analysis of 350 operative observations of renal carcinoma. Clinical and morphologic (macro-, microscopic, electron microscopic, and angiographic) characteristics of this tumor are described, the differential diagnostic criteria of oncocytoma and renal-cell carcinoma are discussed, as is the prognosis of this condition. The authors point to the possibility of oncocytoma growth into the renal capsule, of invasion into the intra- and extratumor veins, of metastases to the lymph nodes. They recommend distinguishing between well- and intermediately differentiated oncocytomas, for this factor determines the course and prognosis of the disease.     

An Electron Microscopic Study of Hepatic Angiomyolipoma

Three cases of hepatic angiomyolipoma, each composed of an intimate mixture of numerous abnormal blood vessels and various-sized fat, spindle and/or epithelioid cells, are presented along with the findings of an electron microscopic study. The spindle cells were confirmed to be smooth muscle by immunohistochemical staining for des-min and by their ultrastructural characteristics. The mature fat cells, smooth muscle cells, immature short spindle cells apparently intermediate or transitional between the former two cell types, and the epithelioid cells were observed adjacent to the endothelial cells. Ultra-structurally, the epithelioid cells were characterized by unusual cytoplasmic organelles such as myofilaments having focal densities and dense attachments, numerous large electron-dense bodies, and a large number of glycogen particles and lipid droplets. Therefore, it is considered that the immature short spindle and epithelioid cells in hepatic angiomyolipoma might be primitive mesenchymal cells having an ability to differentiate toward both smooth muscle and fat cells. Acta Pathol Jpn 39 : 743-749, 1989.     

Angiomyolipoma with epithelial cysts of the kidney in a man

Angiomyolipoma (AML) is a well-characterized tumor composed of vascular, smooth muscle and adipose elements. Recently, AML with epithelial cysts (AMLEC) has been described as a cystic variant of AML. Herein is reported an AMLEC in a 55-year-old man, and to the authors' knowledge this is the first case report of AMLEC in Japan. He was referred to hospital because of microhematuria. A left renal tumor was noted and partial nephrectomy was performed. Histology indicated that the tumor was composed of epithelial cysts, compact subepithelial stroma and muscle-predominant AML. Immunohistochemically, the subepithelial compact stroma and muscle-predominant AML were positive for HMB-45, estrogen receptor (ER), progesterone receptor (PR), CD10, smooth-muscle actin and desmin. Epithelial cysts were positive for pancytokeratin but negative for HMB-45, ER and PR. This tumor was diagnosed as AMLEC, mainly based on the immunohistochemical result that subepithelial compact stroma and muscle-predominant AML were positive for HMB-45. The patient was alive with no evidence of recurrence at 2 years postoperatively. This case was very interesting because it suggests that AMLEC should enter into the differential diagnosis of adult renal neoplasms.     

肾血管平滑肌脂肪瘤的综合影像学诊断评价与病理

目的 结合手术病理结果,评价肾血管平滑肌脂肪瘤的影像学诊断.材料和方法 收治15例RAL患者其中11例经手术病理证实,4例由CT确诊.分析其腹平片、肾盂造影、B超、CT和病理资料,评价不同影像手段对本病诊断的价值和限度.结果 膜部平片和肾盂造影无特征性;B超典型表现为强回声光团,当肿瘤内含脂肪细胞较少或合并出血时可呈不典型的混合型或低回声型;CT发现肿块内脂肪低密度和低CT值为本病的特征.当表现为软组织密度时难与肾癌鉴别.结论 RAL的影像学表现与肿瘤的病理特点密切相关.B超和CT具有定性作用.不典型者仍须进一步检查.     

Angiomyolipoma of the large intestine: report of a case.

A case of an angiomyolipoma of the large intestine occurring in a 55-year-old man without evidence of tuberous sclerosis is reported. Endoscopically, the lesion resembled a sessile adenomatous polyp. The tumor measured 1 cm. Histologic examination revealed a lesion composed predominantly of spindle and epithelioid cells with significant nuclear atypia. Mitoses were rare. The tumor was strongly positive for HMB-45, CD68, vimentin, desmin, and smooth muscle actin. Rare scattered cells reacted with CD34. No residual tumor was found in the resected colon.