硬化性血管周上皮样细胞肿瘤

具有血管周上皮样细胞分化的肿瘤（PEComas）是间胚叶肿瘤的一个家族，包括血管肌脂肪瘤、肺透明细胞“糖”瘤、淋巴管肌瘤病和发生在软组织、内脏器官和皮肤的一组罕见病变。作者描述了一种特殊变异的PEComa，表现为广泛的间质透明变性，该特征先前在这些肿瘤中尚未描述过。     

腹膜后恶性血管周上皮样细胞肿瘤的临床病理分析

目的:探讨腹膜后血管周上皮样细胞肿瘤(perivascular epithelioid cell neoplasms,PEComas)的临床和病理学特点,提高对PEComas的认识和诊断水平。方法:对1例腹膜后恶性PEComas进行临床病理分析及免疫组织化学研究,并复习相关文献。结果:肿瘤组织主要由上皮样细胞构成,胞质丰富、透明或嗜酸性颗粒状,间质富于血管。免疫组织化学显示:肿瘤细胞平滑肌肌动蛋白、HMB45,melan A及Desmin阳性,上皮膜抗原和vimentin局灶阳性,CgA,Syn,S-100,CD117,CD34,细胞角蛋白,calretinin及inhibin均阴性。结论:腹膜后PEComas是一种非常罕见的肿瘤,具有独特的组织学和免疫组织化学特征,应与腹膜后其他上皮样细胞肿瘤进行鉴别。     

CD1a在具有血管周上皮样细胞分化的肿瘤中的表达

按照WHO肿瘤新分类，具有血管周上皮样细胞分化的肿瘤（PEComas）是由组织学和免疫组织化学上有独特表现的血管周上皮样细胞构成的间叶性肿瘤。一般来说，几乎所有PEComas的免疫组织化学标记均具有黑色素细胞[HMB-45和（或）melan A]和平滑肌细胞[SMA和（或）desmin]的标记呈阳性表达的现象。     

HMB-45在普通型子宫平滑肌肉瘤中的表达

子宫平滑肌肉瘤具有从高分化到低分化较宽的形态学谱系变化。在谱系的一端是分化好的肿瘤细胞，由梭形细胞组成，平滑肌细胞容易识别，细胞具有非典型性，核分裂象和凋亡增多。在谱系的另一端肿瘤分化差，除上述表现外，还有大量的间变和多核巨细胞。此外，一些平滑肌肿瘤由HMB-45阳性的上皮样透明细胞组成，称为血管周上皮样细胞肿瘤（PEComa）。     

子宫血管周上皮样细胞肿瘤临床病理观察

目的研究子宫血管周上皮样细胞肿瘤的病理学特征、诊断、鉴别诊断和生物学行为。方法对5例子宫血管周上皮样细胞肿瘤进行常规组织学和免疫组织化学（SP法）染色和观察,对患者进行随访,并复习相关文献。结果光镜下5例肿瘤均由透明或嗜酸细胞巢或宽窄不等的细胞索组成,间质有丰富的小血管和程度不等的透明变。免疫组织化学染色示5例瘤细胞均黑色素细胞标记阳性和程度不等的结蛋白和平滑肌肌动蛋白（SMA）阳性,CK和CD10阴性。5例患者现均存活。结论子宫血管周上皮样细胞肿瘤具有较特征性的组织病理及免疫组织化学特点,HMB45阳性对诊断有重要作用。该肿瘤分良性、恶性潜能不能确定和恶性三类,应与透明细胞癌和上皮样平滑肌肿瘤区别。     

4例胃肠道血管周上皮样细胞肿瘤临床病理学分析

目的 探讨胃肠道血管周上皮样细胞肿瘤(perivasculaRepithelioid cell tumor,PEComa)的临床及病理学特点.方法 回顾性复习4例胃肠道原发血管周上皮样细胞肿瘤的病理切片及临床资料,选取典型蜡块做相关的免疫组化染色,抗体包括黑色素相关抗原HMB45、melan-A、肌源性标记抗原SMA、desmin,以及vimentin、CgA、CK、S-100、CD117、CD34.结果 4例PEComas中男性3例,女性1例,年龄分别为36、38、42及45岁.其中2例位于升结肠,1例位于降结肠,1例位于乙状结肠.肿瘤大小4.5～10 cm,境界清楚,切面灰白色,质地均匀,局部可见出血.镜检:肿瘤细胞呈上皮样排列,细胞质丰富,透亮或嗜酸性颗粒状,细胞核空泡状,有明显的核仁,间质富于毛细血管、血窦以及厚壁血管.细胞异型性小,个别病例局部可见轻～中度异型性,分裂象0～3个/10 HPF.免疫组化结果 :肿瘤弥漫表达HMB45(4/4),弥漫或片状表达vimentin(4/4)、SMA(4/4)以及desmin(3/4).CgA、Syn、CK、S-100、CD117、CD10及CD34均阴性.4例患者行局部肠管及肿瘤切除,术后随访8、15、32及36个月均无复发和肿瘤转移.结论 胃肠道PEComa少见,为低度恶性潜能肿瘤,形态类似于软组织和其他部位的同类肿瘤,手术切除为首选治疗.     

子宫血管周上皮样细胞肿瘤3例临床病理分析

目的探讨子宫血管周上皮样细胞肿瘤(perivascular epithelioid cell tumor,PEComa)的临床病理特征、诊断及鉴别诊断等。方法采用免疫组化EnVision两步法对3例子宫PEComa进行检测,并复习相关文献。结果3例肿瘤由梭形细胞和上皮样细胞构成,胞质透明至嗜酸性,间质血管丰富,其中1例肿瘤细胞异型性显著,并见出血、坏死。免疫表型:3例HMB-45阳性,2例SMA、Caldesmon阳性,Melan-A、TFE-3、desmin、CD10、CD117和S-100蛋白均阴性,Ki-67增殖指数5%~30%。随访4~55个月,患者均存活。结论子宫PEComa是一种少见的间叶源性肿瘤,结合组织学形态及免疫表型可辅助诊断。     

硬化型上皮样血管肌脂肪瘤

作者报道了2例罕见的上皮样血管肌脂肪瘤（AML），具有显著的硬化间质。2例中年女性患者，无结节性硬化症临床病史。例1发生在肾皮质，直径2cm，例2为肾旁腹膜后肿瘤，直径13cm。2个肿瘤由片状或巢状多角形上皮样或短梭形细胞组成，一致的圆形至卵圆形核，胞质嗜酸性，其间伴有束状透明变性的硬化性间质。例2肿瘤内有小区域看似成熟的脂肪细胞。免疫组化显示2例上皮样肿瘤细胞actin和desmin广泛阳性，MART-1阳性，2例硬化性间质束内有散在HMB-45阳性的细胞。而上皮样肿瘤细胞HMB-45实质上是阴性。作为上皮样血管肌脂肪瘤的亚型或硬化性血管周上皮样细胞肿瘤。作者报道的2例临床病理和免疫组化特征是相似的。     

血管周上皮样细胞分化肿瘤的研究进展

血管周上皮样细胞分化的肿瘤(neoplasms with perlvascular epithelioid cell differentiation,PEComa)是一组较少见组织学和免疫表型上具有血管周上皮样细胞特征的间叶肿瘤,瘤细胞胞质透明或嗜酸性颗粒状,免疫组化检测表达黑色素瘤抗体HMB45、Melan—A(A103)及肌源性抗体SMA。包括肝肾血管平滑肌脂肪瘤(angiomyolipoma,AML)、肺的透明细胞“糖”瘤(clear cell“sugar”tunlour of the hmg．CCST)、     

恶性血管周上皮样细胞肿瘤2例并文献复习

目的 探讨恶性血管周上皮样细胞肿瘤(malignant perivascular epitheliod cell tumor,PEComa)的临床、病理特征及鉴别诊断.方法 对2例恶性PEComa进行临床、病理形态学、免疫表型及电镜观察,并复习相关文献.结果 镜下见肿瘤组织由梭形细胞及上皮样细胞构成,细胞异型性明显,细胞胞质透明或嗜酸,细胞核大,有核仁,瘤细胞由纤细的纤维结缔组织及薄壁血管将其分隔成巢状、腺泡状、片状结构,部分区域可见多核瘤巨细胞伴肿瘤坏死,核分裂多见.免疫表型:肿瘤细胞表达HMB-45、S-100、SMA及desmin;电镜下见肿瘤细胞胞质内可见高电子密度核心的内分泌小体和少许不成熟的黑色素小体.结论 恶性PEComa罕见,病理形态多样,熟悉其临床、病理形态、免疫表型及电镜下改变,有助于临床、病理医师对其正确诊断及鉴别诊断.     

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.     

Ultrasound‐guided fine needle aspiration cytology in the diagnosis of hepatic and pancreatic perivascular epithelioid cell tumors: A case series

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors that can affect any part of the body. They can be sporadic or arise in the setting of tuberous sclerosis (TSC). In this article, we report a series of three hepatic and two pancreatic PEComas diagnosed preoperatively with ultrasound‐guided fine needle aspiration (FNA). All patients were female (age range 28‐70), had no personal history of TSC and presented with a single, localized painless mass. Rapid on‐site evaluation (ROSE) of cytologic samples was performed for all cases to evaluate for cellular content and adequacy of specimens. Direct smears and cell block preparations revealed a proliferation of medium to large polygonal epithelioid cells, with abundant eosinophilic and vacuolated cytoplasm, arranged in sheets and nests. On immunohistochemistry (IHC), neoplastic cells showed co‐expression of melanocytic and smooth muscle markers and a diagnosis of PEComa was rendered. PEComas of the pancreas and liver are rare neoplasms, but should always be considered when examining “clear cell” neoplasms, especially in young female patients. If good quality cytologic samples are obtained by FNA, a correct diagnosis can be achieved with the help of IHC. This is of particular importance in order to plan adequate surgical strategy and to avoid overtreatment.     

Sclerosing variant of perivascular epithelioid cell tumor in the female genital organs

Perivascular epithelioid cell tumor (PEComas), other than angiomyolipoma, clear cell 'sugar' tumor of the lung, and lymphangioleiomyomatosis, is an uncommon mesenchymal neoplasm that arises in the soft tissue and visceral organs. We report herein two cases of sclerosing PEComa; a distinctive variant of PEComa, which is characterized by extensive stromal hyalinization, occurring in the uterus and broad ligament. The patients were 34- and 51-year-old females with no family history of tuberous sclerosis complex. Macroscopically, the tumors had white to gray cut surfaces and were microscopically composed of predominantly spindle- to polygon-shaped cells with clear to slightly eosinophilic cytoplasm and pleomorphic nuclei focally arranged in a perivascular pattern, accompanied by marked stromal hyalinization. These tumor cells were immunohistochemically positive for HMB45 and α-smooth muscle actin. Although this variant of PEComa is very rare, this entity should be considered as a potential primary neoplasm of the female genital organs.     

Malignant perivascular epithelioid cell tumor of the colon: report of a case with molecular analysis

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm, and malignant cases are extremely rare. A case of malignant PEComa arising in the colon is described herein. The patient was a 43-year-old Japanese woman without a history of tuberous sclerosis complex. The tumor occurred in the abdominal cavity attached to the serosal side of the descending colon. Histologically, the tumor consisted of sheets or closely packed nests of epithelioid cells with clear or eosinophilic cytoplasms. The tumor cells were positive for HMB-45 but negative for S-100 protein and cytokeratins by immunohistochemical staining. Ki-67 labeling index was 2.9%. Peritoneal dissemination of tumor occurred at 20 months and the patient died of tumor at 38 months after the initial operation. This was considered to be a case of malignant PEComa, based on the histological and clinical features. Tumor cells showed overexpression of cyclin D1 but lacked the loss of heterozygosity of the TSC1 and TSC2 genes. The result suggests that the overexpression of cyclin D1 may play an important role in the tumorigenesis of PEComa. Because PEComas can behave in an aggressive manner, careful follow up is warranted.     

Activation of the mTOR pathway in sporadic angiomyolipomas and other perivascular epithelioid cell neoplasms

Angiomyolipoma (AML) belong to a family of tumors known as perivascular epithelioid cell tumors (PEComas) that share a common immunophenotypic profile of muscle and melanocytic differentiation. These tumors are clonal in nature and have a strong association with tuberous sclerosis. Genetic analyses have reported allelic imbalance at the TSC2 locus on 16p13. In the context of non-tuberous sclerosis complex (TSC), non-lymphangioleiomyomatosis-associated AMLs, and non-renal PEComas, the functional status of the TSC2 signaling pathway has not been reported. Studies over the last several years have uncovered a critical role of the TSC1/2 genes in negatively regulating the Rheb/mTOR/p70S6K cascade. Here, we examined the activity of this pathway in sporadic AMLs and PEComas using immunohistochemical and biochemical analyses. We found increased levels of phospho-p70S6K, a marker of mTOR activity, in 15 of 15 non-TSC AMLs. This was accompanied by reduced phospho-AKT expression, a pattern that is consistent with the disruption of TSC1/2 function. Western blot analysis confirmed mTOR activation concurrent with the loss of TSC2 and not TSC1 in sporadic AMLs. Similarly, elevated phospho-p70S6K and reduced phospho-AKT expression was detected in 14 of 15 cases of extrarenal PEComas. These observations provide the first functional evidence that mTOR activation is common to sporadic, non-TSC-related AMLs and PEComas. This suggests the possibility that mTOR inhibitors such as rapamycin may be therapeutic for this class of disease.     

PEComas: the past,the present and the future

The perivascular epithelioid cell (PEC) is a cell type constantly present in a group of tumors called PEComas. PEC expresses myogenic and melanocytic markers, such as HMB45 and actin. Recently, recurrent chromosomal alterations have been demonstrated in PEC. At present, PEComa is a widely accepted entity. In the past 10 years, the use of this term has allowed to report and describe numerous cases permitting to start highlighting the biology of this group of lesions. PEComas are related to the genetic alterations of tuberous sclerosis complex (TSC), an autosomal dominant genetic disease due to losses of TSC1 (9q34) or TSC2 (16p13.3) genes which seem to have a role in the regulation of the Rheb/mTOR/p70S6K pathway. There are some open questions about PEComas regarding its histogenesis, the definition of epithelioid angiomyolipoma and the identification of the histological criteria of malignancy. An innovative therapeutic trial using rapamycin is under way for tumors occurring in TSC such as renal angiomyolipoma and lymphangioleiomyomatosis. Its success could provide the rationale for the use of the same drug in other lesions composed of PECs, especially in the malignant ones.     

Comparative genomic hybridization study of perivascular epithelioid cell tumor: molecular genetic evidence of perivascular epithelioid cell tumor as a distinctive neoplasm

Perivascular epithelioid cell tumor (PEComa) is a neoplasm composed chiefly of HMB-45-positive epithelioid cells with clear to granular cytoplasm and a perivascular distribution. Such tumors have been reported in different organs under a variety of designations. The cytogenetic features of these neoplasms have not been well studied. We collected 9 tumors (5 of kidney, 1 of prostate, 1 of urinary bladder, 1 of the pelvic cavity soft tissue, and 1 of uterus) from 8 patients, including one patient with tuberous sclerosis complex. The paraffin blocks of tumor tissue were submitted for comparative genomic hybridization analyses. Gross chromosomal aberrances were observed in all cases. The frequent imbalances were losses on chromosome 19 (8 cases), 16p (6 cases), 17p (6 cases), 1p (5 cases), and 18p (4 cases) and gains on chromosome X (6 cases), 12q (6 cases), 3q (5 cases), 5 (4 cases), and 2q (4 cases). The frequent deletion of 16p in which TSC2 gene is located indicates the oncogenetic relationship of PEComas with angiomyolipoma as a TSC2-linked neoplasm. From a molecular genetic perspective, the recurrent chromosomal alterations in both renal and extrarenal tumors further support the concept of PEComa as a distinctive tumor entity regardless of anatomic location.     

Clear-cell proliferation of the lung with lymphangioleiomyomatosis-like change

AIMS: To describe two cases of a peculiar pulmonary lesion, which expand both the morphological and the immunophenotypic spectrum of perivascular epithelioid cell (PEC)-related disorders. METHODS AND RESULTS: One man and one female, with and without the tuberous sclerosis complex (TSC), respectively, showed pulmonary cysts and small nodules on computed tomography scan. In the former, lymphangioleiomyomatosis (LAM) was suspected. In both cases, an open lung biopsy was performed, whose cut surface displayed numerous cysts lined by thin/thick septa. Microscopically, the septa were associated with micronodular or interstitial proliferation of medium/large-sized elements with abundant clear (periodic acid-Schiff-positive/diastase-sensitive) cytoplasm and distinct cell borders, embedded in fibrous tissue. The elements were CD34+, vimentin-positive and, to a lesser extent, HMB-45+ and MART-1+. The stains for specific muscle actin, desmin, S100 protein, CD31, FVIIIRAg, cytokeratins, CD45, CD68, oestrogen and progesterone receptors were all negative. Ki67 labelling was <1%. Electron microscopy displayed cytoplasmic vacuoles containing glycogen particles. The TSC1 and TSC2 gene status could not be assessed because of poor DNA preservation. In the man with TSC, a focus of micronodular pneumocyte hyperplasia was also found. CONCLUSIONS: Because of the coexpression of CD34 and melanoma-associated antigens and the occurrence of TSC in one patient, the cases described here add a new piece to the puzzle of PEC lesions and contribute to the open discussion on the origin of LAM and LAM-like proliferations.     

Malignant perivascular epithelioid cell tumor of the retroperitoneum

Perivascular epithelioid cell tumors (PEComas) are a rare type of mesenchymal neoplasms characterized by a proliferation of perivascular cells with an epithelioid phenotype and expression of myo-melanocytic markers. The majority of PEComas seem to be benign and usually their prognosis is good. Malignant cases are extremely rare, exhibiting a malignant course with local recurrences and distant metastases. We herein report a case of a malignant PEComa arising in the retroperitoneum. The patient was a 55-year-old woman experiencing abdominal discomfort for approximately one month. Ultrasound and computer tomography (CT) scans of the abdomen revealed a solid mass arising from the retroperitoneum. Microscopically, the tumor was composed of epithelioid cells mixed with spindled cells. The nucleus had significant atypia, and the mitoses were obvious. The focal intravascular tumor embolus was visible. Immunohistochemically, the epithelioid tumor cells were positive for HMB45 and Melan-A, and the spindled tumor celLs were positive for SMA and desmin. Seven months after a surgical resection, an ultrasound revealed liver metastases. In conclusion, the malignant PEComas of the retroperitoneum is a very rare neoplasm with unique morphological and immunohistochemical characteristics. It should be differentiated from other epithelioid cell tumors of the retroperitoneum.     

PEComa: what do we know so far?

PEComas (tumours showing perivascular epithelioid cell differentiation) are a family of related mesenchymal neoplasms that include angiomyolipoma, lymphangiomyomatosis, clear cell "sugar" tumour of the lung, and a group of rare, morphologically and immunophenotypically similar lesions arising at a variety of visceral and soft tissue sites. These tumours all share a distinctive cell type, the perivascular epithelioid cell or "PEC' (which has no known normal tissue counterpart). PEComas show a marked female predominance and are composed of nests and sheets of usually epithelioid but occasionally spindled cells with clear to granular eosinophilic cytoplasm and a focal association with blood vessel walls. PEComas appear to arise most commonly at visceral (especially gastrointestinal and uterine), retroperitoneal, and abdominopelvic sites, with a subset occurring in somatic soft tissue and skin. Nearly all PEComas show immunoreactivity for both melanocytic (HMB-45 and/or melan-A) and smooth muscle (actin and/or desmin) markers. A subset of PEComas behave in a malignant fashion. This review examines the members of the PEComa family, with an emphasis on lesions arising outside of the kidney, lung and liver, and discusses preliminary evidence for pathological features that might predict malignant behaviour.