Epithelioid angiomyolipoma of kidney with atypical nuclear features and intranuclear inclusions on cytology

Described herein are the cytological findings of epithelioid angiomyolipoma (EAML) of the kidney with atypical nuclear features mistaken for renal cell carcinoma (RCC) in a 61‐year‐old male patient. Aspirates from this large renal mass were cellular and showed epithelioid cell clusters with focally crowded nuclei showing moderate anisonucleosis, small nucleoli, and prominent eosinophilic intranuclear inclusions. Failure to recognize the scanty adipose tissue component and preponderance of epithelioid cells with nuclear pleomorphism lead to a diagnosis of RCC on cytology. On histology, the tumor was essentially composed of epithelioid and spindle cells that showed the typical immunoprofile of an angiomyolipoma and only occasional foci of typical AML were seen. The hilar lymph node was involved in contiguity. However, in view of lack of obvious features of malignancy, the tumor was labeled as EAML with atypical features. Immunocytochemistry on the destained cytology aspirates revealed strong smooth muscle actin staining of all cells. To conclude, EAML can mimic a RCC. In such instances, lack of arborizing vasculature, absence of cytoplasmic fatty vacoulation, crowded nuclei with intranuclear inclusions, and lack of prominent nucleoli along with typical immunophenotype of EAML may assist in the cytology diagnosis. Diagn. Cytopathol. 2011;39:278–282. © 2010 Wiley‐Liss, Inc.     

肾脏上皮样型血管平滑肌脂肪瘤临床病理分析

目的 探讨肾脏上皮样型血管平滑肌脂肪瘤(EAML)的临床病理特点及诊断与鉴别诊断.方法 通过对3例EAML临床病理学观察与免疫组化标记及复习有关文献,讨论其组织学特征及临床生物学行为.结果 3例年龄分别为28、40和32岁,均有腰痛病史,其中1例伴有肉眼血尿,均无结节硬化症.眼观:肿瘤位于肾脏,直径大小分别为6 cm、8 cm和3 cm.3例境界清楚,例2伴囊性变.肿瘤无包膜,2例出血、坏死明显,质脆或韧.镜检:瘤细胞体积大或巨大,呈多边形,胞质丰富,嗜酸性或空泡状,核仁明显,可见核内包涵体,多核巨细胞散在其中.瘤细胞弥漫性或巢团状排列.2例瘤组织出血、坏死明显,呈浸润性边缘.3例未见典型AML图像.免疫组化染色显示瘤细胞HMB-45阳性,SMA和vimentin散在性阳性,CK、EMA和CD10均阴性.结论 EAML是一种单一方向分化的,含有大上皮样细胞的肿瘤,瘤细胞较为特异的表达HMB-45.辅以免疫组化可以与其它肾脏肿瘤相鉴别.     

Tuberous sclerosis and the relation with renal angiomyolipoma. A genetic study on the clinical aspects

Renal angiomyolipomas were present in 23 out of a series of 38 patients with proven tuberous sclerosis (60.5%). Multiplicity and bilateral localization of combined renal angiomyolipomas were important differences between this category and the isolated, usually solitary, angiomyolipomas. One of the parents of a patient with tuberous sclerosis had small renal angiomyolipomas without signs of tuberous sclerosis. This indicates that renal angiomyolipomas might be a forme fruste of tuberous sclerosis. Two patients with suspected isolated renal angiomyolipomas proved to have tuberous sclerosis. From this study we can conclude that multiple angiomyolipomas, or a combination of a single renal hamartoma with one of the signs suggestive of tuberous sclerosis, warrant a thorough examination to exclude tuberous sclerosis.     

Constant allelic alteration on chromosome 16p (TSC2 gene) in perivascular epithelioid cell tumour (PEComa): genetic evidence for the relationship of PEComa with angiomyolipoma

Perivascular epithelioid cell tumours (PEComas) are a family of tumours including classic angiomyolipoma, lymphangioleiomyomatosis, and clear epithelioid cell tumours reported under a variety of names such as epithelioid angiomyolipoma, pulmonary and extrapulmonary clear cell sugar tumour, and PEComa. Our previous comparative genomic hybridization study of PEComas demonstrated recurrent chromosomal aberrations including deletions on chromosome 16p, where the TSC2 gene is located. In this study, we focused on the alteration of chromosome 16p, including TSC2. We collected ten sporadic and two tuberous sclerosis complex-associated PEComas, as well as 14 sporadic classic hepatic and renal angiomyolipomas (AMLs) as controls. We used 16 microsatellite markers distributed along chromosome 16p to test for allelic imbalances on chromosome 16p and at TSC2, and two markers for TSC1. Furthermore, we carried out immunohistochemical staining for phospho-p706K, phospho-AKT, and phospho-S6 to evaluate the effect of TSC2 alterations on the mTOR signalling pathway. Loss of heterozygosity (LOH) was found in 11 PEComas and involved the region of the TSC2 locus in seven. Six classic angiomyolipomas had allelic changes at chromosome 16p. Microsatellite instability was detected in two PEComas. The incidence of genetic aberrations was significantly higher in the PEComa group. Only one PEComa showed LOH at the TSC1 locus. Eleven PEComas and 13 AMLs revealed elevated phospho-p70S6K accompanied by reduced phospho-AKT. Five PEComas and eight classic angiomyolipomas were positive for phospho-S6. The phosphorylation profile indicates functional activation of the mTOR pathway through a disrupted TSC1/2 complex. Our observations of frequent deletion of TSC2 and the mTOR signalling pathway provide evidence that the oncogenetic lineage of PEComa, as a distinct TSC2-linked neoplasm, is similar to that of angiomyolipoma.     

Renal angiomyolipomas: could the histology serve as a marker for tuberous sclerosis?

The histological features of 43 renal angiomyolipomas were studied in an attempt to evaluate whether the isolated forms and those that present as part of the tuberous sclerosis complex can be distinguished. In two patients the mass was classified as an angioleiomyoma, because no adipose tissue was present. All renal angiomyolipomas showed the same basic histological picture. The combined forms, however, showed additional features such as extension into pre-existent renal parenchyma, scattered foci of hamartomatous lesions, calcified spicules and tubular inclusions. The findings suggest that these features, in an otherwise classical angiomyolipoma, should alert the pathologist to the possibility of tuberous sclerosis.     

Renal cell carcinoma arising in a long pre-existing angiomyolipoma

Angiomyolipoma (AML) is a mixed mesenchymal tumor belonging to the family of perivascular epithelioid cell tumors. Concurrent development of AML and adult renal cell carcinoma (RCC) is very rare. Herein is presented a unique case in which RCC arose within a previously detected AML tumor mass. A 40-year-old woman had been diagnosed with AML of the right kidney. Fifteen years later, during a regular radiographic examination, a new lesion was detected at the lower pole of the right kidney adjacent to the previously described AML. Because RCC was clinically suspected, the patient underwent right nephrectomy. Macroscopically, the tumor had a yellowish, transparent, fatty area and an opaque yellowish area with cystic features. Microscopically, the former tumor, consisting of an admixture of mature adipose tissue with smooth muscle and vascular tissue, was diagnosed as AML. The latter tumor was diagnosed as RCC (clear cell type). RCC was not completely enclosed within the AML, but overlapped it. No fibrous capsule was found between these tumors. Although this situation is very rare, from a clinical and pathological point of view it is important to consider the possibility that RCC might arise within AML. The relationship between the two lesions is discussed with a review of the literature.     

上皮样血管平滑肌脂肪瘤的临床病理特征

目的:探讨上皮样血管平滑肌脂肪瘤(epithelioid angiomyolipoma,EAML)的临床病理学特征.方法:回顾性分析17例病理诊断为EAML的组织学形态、免疫组织化学特点、临床及随访资料.结果:男5例,女12例,年龄21~62(平均31.2)岁,其中14例发生于肾脏(3例伴有子宫平滑肌瘤,2例伴有宫内孕);2例发生于肝脏,1例发生于腹腔;肿瘤最大径3~15 cm,镜下瘤细胞呈上皮样巢、片状分布,可见围绕血管呈放射状排列的结构;细胞体积大,卵圆形、梭形,胞质丰富,异型明显,核分裂少见,其中2例伴有出血、坏死.免疫组织化学HMB-45,Melan-A,SMA阳性,vimentin,ER和PR表达率分别为41%(7/17),23%(4/17)以及35%(6/17).17例EAML均行肿瘤根治或肿瘤切除术,术后随访5~52个月,1例2年后肝肺转移死亡,其余16例均健在,无复发及转移.结论:EAML多发生于女性,可能与激素水平有关;肾脏最常见,其次为肝、腹腔;病理形态多样,免疫组织化学对其诊断有重要价值,手术效果好,有转移可能.     

Angiomyolipoma of the kidney. Immunoreactivity with HMB-45. Light- and electron-microscopic findings

Immunoreactivity with HMB-45 has recently been described in renal angiomyolipoma, a tumour of smooth muscle cells. HMB-45 is a monoclonal antibody that reacts specifically with melanosomes. In order to determine whether the tumour cells contain melanosomes and synthesize melanin, seven tumours were studied by light microscopy and immunohistochemically with the antibodies HMB-45, KP1 (CD68), PG-M1 (CD68), Ki-M1P, anti-lysozyme, anti-smooth-muscle actin, anti-vimentin, anti-S100 protein and KL1 (anti-keratin). Two tumours were also studied by electronmicroscopy and one by immuno-electronmicroscopy. Histochemical investigation for dopa oxidase was performed on cryostat sections. The tumours contained varying numbers of HMB-45-positive muscle cells. Reactivity was noted in lysosomal granules and rough endoplasmic reticulum. Typical premelanosomes were found in the tumour cells by electronmicroscopy. Groups of tumour cells stained for dopa oxidase. The tumour cells were not reactive for lysozyme, but reacted with KP1, PG-M1 and Ki-M1P. Immuno-electronmicrosopy showed that reactivity for KP1 was located within lysosomal granules. The findings show that the tumour cells of renal angiomyolipoma contain premelanosomes and that they are able to synthesize melanin, because they contain dopa oxidase. Immunoreactivity with KP1, PG-M1 and Ki-M1P can be attributed, in the absence of staining for lysozyme, to the large number of lysosomal granules. The tumour cells were not found to be related to macrophages or myeloid cells.     

Epithelioid angiomyolipoma of the liver with striking giant cell component: Fine‐needle aspiration biopsy findings of a rare neoplasm

Angiomyolipoma (AML) is a uncommon benign neoplasm of the liver with cyto‐ and histologic features similar to the more commonly encountered renal AML. Tumors composed predominantly of epithelioid cells have been referred to as epithelioid AML. Because most liver lesions are first evaluated by fine‐needle aspiration biopsy (FNAB), it is important to distinguish this variant of AML from more common hepatic neoplasms such as hepatocellular carcinoma (HCC) or metastatic tumors. Rare reports of epithelioid AML of the liver diagnosed by FNAB are in the literature. Here, we describe the cytologic findings of a unique case of epithelioid AML with numerous giant cells. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

肾上皮样血管平滑肌脂肪瘤肺转移1例报告并文献复习

目的：探讨肾上皮样血管平滑肌脂肪瘤病理特点及生物学行为。方法：对1例低热患者行肺肿块穿刺活检,然后行HE染色和免疫组织化学染色。复习肾肿瘤病理切片并进行文献复习。结果：穿刺活检病理分析：密集分布的上皮样细胞,细胞体积大,呈圆形、多边形;异型明显;无血管平滑肌脂肪瘤结构;免疫组织化学：人黑色素瘤蛋白阳性,平滑肌肌动蛋白阳性,上皮膜抗原阴性。病理诊断：左肺上皮样血管平滑肌脂肪瘤;考虑来源于肾。结论：上皮样血管平滑肌脂肪瘤是一种有恶性潜能的间叶性肿瘤,可以发生远处转移。     

肾脏不典型血管平滑肌脂肪瘤4例报道并文献复习

目的：探讨肾脏不典型血管平滑肌脂肪瘤（ａｔｙｐｉｃａｌ ａｎｇｉｏｍｙｏｌｉｐｏｍａ,ＡＡＭＬ）的临床病理特征。方法：收集４例曾误诊为肾肉瘤样癌或恶纤组的ＡＡＭＬ行光镜、免疫组化观察,并对其中１例和另３例典型ＡＭＬ作电镜观察。结果：ＡＡＭＬ具有以下的病理特点：①肉眼上切面呈棕褐色,可伴有坏死及出血;②光镜下表现为富细胞,主要由胞浆丰富嗜酸性的单核或多核多形性瘤巨细胞和梭形的肉瘤样细胞及胞浆透明成片     

The TSC-2 product tuberin is expressed in lymphangioleiomyomatosis and angiomyolipoma

AIMS: Lymphangioleiomyomatosis is categorized by proliferation of abnormal smooth muscle cells (LAM cells) in the lungs and lymphatics and the presence of angiomyolipomas. Recently mutations in the tuberous sclerosis complex-2 gene (TSC-2) have been described in LAM cells and angiomyolipomas. The TSC-2 protein tuberin is a tumour suppressor and its loss may result in cellular proliferation. We used immunohistochemistry to test the hypothesis that uncontrolled cellular proliferation in lymphangioleiomyomatosis is the result of reduced tuberin protein expression. METHODS AND RESULTS: Tissue from normal lung, normal kidney, lymphangioleiomyomatosis and angiomyolipomas was immunostained with three separate anti-tuberin antibodies. Tuberin staining in normal tissues was similar to that previously described. Surprisingly, tuberin was strongly expressed in the LAM cells of all cases of lymphangioleiomyomatosis and angiomyolipoma at a greater level than in normal smooth muscle cells. The perivascular cells of angiomyolipomas, however, did not stain for tuberin. CONCLUSIONS: Our results suggest that a loss of tuberin protein in LAM cells is not the cause of the cellular proliferation seen in lymphangioleiomyomatosis. Lymphangioleiomyomatosis may result either from the expression of a mutant tuberin with abnormal function, as a result of mutations in functionally related proteins, or from more than one mechanism.     

Primary monotypic epithelioid angiomyolipoma of bone

AIMS: Monotypic epithelioid angiomyolipoma is a distinct and definable variant of angiomyolipoma, composed of monomorphous epithelioid cells that show HMB45 immunoreactivity. Angiomyolipoma, including its morphological variants, belongs to the family of perivascular epithelioid cell tumour. METHODS AND RESULTS: The tumour was examined using immunohistochemical staining and by transmission electron microscopy. Neoplastic cells showed a cytoplasmic granular positivity for HMB45. CONCLUSIONS: Extrarenal angiomyolipomas are rare and, to the best of our knowledge, this is the first reported case of a primary monotypic epithelioid angiomyolipoma of bone in a patient without evidence of tuberous sclerosis.     

Renal epithelioid angiomyolipoma: a study of six cases and a meta-analytic study. Development of criteria for screening the entity with prognostic significance

Aims:  Renal epithelioid angiomyolipoma (EAML) is only described in case reports or in multi-institutional small series. The aim was to report cases seen at our institution and to perform a meta-analysis based on a literature review.
Methods and results:  Six EAML cases seen at our institution were reviewed and a meta-analysis performed using cases retrieved from a literature review. There were a total of 69 cases for review. The male:female ratio was 1:3. In the absence of areas of typical AML, useful features in distinguishing EAML from epithelial renal neoplasms include: extreme degree of cytological atypia, histiocytoid appearance, presence of melanocytic pigments, solid architecture with the absence of frequent areas of alveolar pattern, tubulo-papillary formation and scarring. A fatal outcome, distant or lymph node metastasis, venous invasion and local recurrence were considered as adverse events and occurred in 40% of cases over a period of follow-up of 3–60 months (mean 22.5 ± 18 months). Tumours with an unfavourable outcome showing marked cytological atypia and extensive tumour necrosis were larger (135 ± 43 mm) than those with a favourable outcome (79 ± 50 mm) ( P  < 0.002), and predominantly occurred in men.
Conclusions:  Renal neoplasms with certain unusual features should be investigated immunohistochemically to rule out the possibility of EAML. The frequency of adverse outcome is lower in EAML than in renal cell carcinoma.     

Lymphangiomyomatosis and angiomyolipoma: closely related entities characterized by hamartomatous proliferation of HMB-45-positive smooth muscle

Angiomyolipoma is a hamartomatous condition which can occur as a component of the tuberous sclerosis complex. Lymphangiomyomatosis, another hamartomatous lesion occurring predominantly in the lungs, has long been suspected to be related to angiomyolipoma and tuberous sclerosis because of occasional clinical associations. We undertook this study to provide further support for the close relationship between these two entities. Five cases of lymphangiomyomatosis and 20 case of angiomyolipoma were retrieved for histological review and immunohistochemical studies. The antibodies used were anti-muscle specific actin (HHF-35), anti-desmin (D33) and antimelanoma (HMB-45). Lesions featuring smooth muscle proliferation were used as controls. The proliferated smooth muscle cells in both lymphangiomyomatosis and angiomyolipoma were much plumper and paler or even clear, when compared with the deeply eosinophilic cytoplasm of the normal spindly smooth muscle cells and those of leiomyomas. Their nuclei were round to oval and pale rather than elongated and dark. Cells with bizarre nuclei were commoner in angiomyolipoma (18/20 cases) than lymphangiomyomatosis (1/5). In 12 cases of angiomyolipoma there were foci indistinguishable from lymphangiomyomatosis, i.e. plump spindle cells arranged in short fascicles around ramifying endothelium-lined spaces. All five cases of lymphangiomyomatosis stained for muscle-specific actin, desmin and HMB-45. For angiomyolipomas, the positivity rates for these markers were: 20/20, 17/20 and 18/20, respectively, including one case that was negative for both desmin and HMB-45. The various smooth muscle proliferations and tumours selected as controls were uniformly HMB-45 negative. The distinctive cytological features, morphological overlap and immunophenotypic profile all support a close relationship between lymphangiomyomatosis and angiomyolipoma, which probably represent different morphological manifestations of hamartomatous proliferation of a peculiar form of HMB-45-positive smooth muscle.     

Sclerosing variant of epithelioid angiomyolipoma

Presented herein are two unusual epithelioid angiomyolipomas (AML) displaying prominent stromal sclerosis. Both patients were middle-aged women without a clinical history of tuberous sclerosis. One patient (case 1) had a 2 cm lesion arising in the renal cortex, and another (case 2) had a pararenal retroperitoneal tumor measuring 13 cm. Both tumors were composed of sheets or nests of polygonal epithelioid or short spindle cells having uniform round to oval nuclei and eosinophilic cytoplasm with cords of hyalinized sclerotic stroma between them. The tumor in case 2 had small areas of mature-looking fat cells. Immunohistochemically, epithelioid tumor cells were diffusely positive for actins and desmin in both cases, and melanoma antigen recognized by T cells (MART)-1 was positive in patient 2. Scattered HMB-45-immunoreactive cells were identified in the sclerotic cords of both tumors, but epithelioid tumor cells were essentially negative for HMB-45. The characteristic clinicopathological and immunohistochemical features of the present cases are analogous to a subset of epithelioid AML or sclerosing perivascular epithelioid cell tumors previously reported.     

上皮样血管平滑肌脂肪瘤7例临床病理分析

目的回顾分析上皮样血管平滑肌脂肪瘤(epithelioid angiomyolipoma,EAML)的形态学特点、免疫表型、诊断及鉴别诊断、临床特点及预后,加深对EAML的认识,提高诊断的准确性。方法观察7例EAML的病理形态学、免疫表型及临床特征。结果 7例EAML形态相似,肿瘤细胞体积大,呈卵圆形、梭形或多边形,胞质丰富,嗜酸性,细胞核大,大小不一,核仁明显,可见多核及巨核瘤细胞,有少数核分裂象,呈巢、片状分布,部分围绕血管呈袖套状。免疫表型:肿瘤细胞HMB-45、Melan-A、vimentin、SMA均弥漫阳性,EMA、CK、CD10均阴性。7例EAML均行肿瘤根治性手术或肿瘤切除术,术后随访3~56个月,除1例因有高度恶性十二指肠间质瘤病史于3个月后死于恶性间质瘤进展外,其余6例均健在,多次复查B超、CT等均无复发、转移。结论 EAML是具有恶性潜能的间叶源性肿瘤,病理形态学上易误诊为恶性肿瘤,免疫组化对鉴别诊断有重要的意义,目前手术治疗是主要方法,有复发或转移可能。     

Unilateral cystic disease of the neonatal kidney: a rare presentation of tuberous sclerosis

Two renal lesions have been described in tuberous sclerosis, angiomyolipomas and cysts. We report a newborn male infant in whom massive cystic enlargement of one kidney was the first manifestation of the disease.     

肝脏单形性上皮样血管平滑肌脂肪瘤

目的：探讨肝脏单形性上皮样血管平滑肌脂肪瘤的临床病理学特征及诊断、鉴别诊断要点。方法：对1例单形性上皮样血管平滑肌脂肪瘤进行临床病理学分析及免疫组织化学研究。结果：肝脏单形性上皮样血管平滑肌脂肪瘤临床多无症状,光镜下单形性上皮样血管平滑肌脂肪瘤由形态多样的上皮样细胞构成,胞质透明或嗜酸,无脂肪组织及异常血管;免疫表型;HMB45阳性,SMA及vimentin部分阳性,desmin少数阳性,S－100蛋白弱阳性,cytokeratin及AFP阴性,CD34血管内皮细胞阳性。结论：肝脏单形性上皮样血管平滑肌脂肪瘤是极为罕见的间叶性肿瘤,组织起源至今不明,其诊断及鉴别诊断主要依靠病理组织学及免疫组织化学。