Monotypic epithelioid angiomyolipoma of the liver

AIMS: Monotypic epithelioid angiomyolipoma is a recently recognized renal tumour, which is composed purely of epithelioid cells coexpressing markers of both smooth muscle differentiation and melanogenesis (HMB45). We report here the first case of monotypic epithelioid angiomyolipoma arising in the liver. CASE DETAILS: A 30-year-old woman without tuberous sclerosis complex (TSC) was incidentally found to have a hepatic mass by ultrasonography. Grossly, the resected tumour showed a nodule-in-nodule appearance, with large areas of haemorrhagic necrosis. Microscopically, the tumour was composed of pleomorphic epithelioid cells with clear, eosinophilic cytoplasm. Neither adipocytes nor abnormal vessels were recognized in the tumour. Immunohistochemically, the tumour cells were strongly positive for HMB45 and S100 protein, focally positive for desmin, vimentin and smooth muscle actin, and negative for epithelial markers (cytokeratins, EMA). Ultrastructural analysis showed numerous dense granules with some striated ones resembling melanosomes, myofilaments and pinocytic vesicles in the cytoplasm. Molecular analysis showed no allelic loss of the TSC2 region or 12 other chromosomal regions. The patient is free of disease over 1 year after the operation. CONCLUSION: We consider that this hepatic tumour is closely related to angiomyolipoma, and a counterpart of renal monotypic epithelioid angiomyolipoma.     

Monotypic epithelioid angiomyolipoma of the adrenal gland: an unusual site for a rare extrarenal tumor

Epithelioid angiomyolipoma (AML) is an uncommon renal mesenchymal tumor with malignant potential and is frequently associated with tuberous sclerosis. Extrarenal AMLs are rare, and to the best of our knowledge, this is the first reported case of a primary monotypic epithelioid AML of adrenal gland in a patient without evidence of tuberous sclerosis. The patient is a 42-year old man who presented with retroperitoneal hemorrhage resulting from spontaneous rupture of adrenal mass. Histologically, the tumor showed a prominent component of epithelioid smooth muscle cells with slightly pleomorphic nuclei, sometimes with prominent nucleoli and eosinophilic cytoplasm resembling oncocytic tumors. Epithelioid cells were positive for melanoma (HMB45 and positive MelanA) and smooth muscle markers (α-smooth muscle–specific actin), but not for epithelial markers (cytokeratin, EMA). Differential diagnosis from renal cell carcinoma, adrenal gland carcinoma, and metastatic carcinoma is often challenging because of its epithelioid morphology. Because primary and secondary malignant tumors are much more common and aggressive neoplasms, establishing the correct diagnosis has important therapeutic and prognostic implications.     

Clinicopathologic features of renal epithelioid angiomyolipoma: report of one case and review of literatures

Epithelioid angiomyolipoma (EAML) is a rare renal mesenchymal tumor with malignant potential and is frequently associated with tuberous sclerosis complex (TSC). As metastasis of the tumor cells occur early, EAML is considered a potentially malignant tumor type and intrigues further research on it. Under the microscope, we could find the tumor was composed of atypical polygonal cells sheet mixed with classic angiomyolipoma (AML) components such as blood vessels with notable thick vascular walls, smooth muscle-like cells and adipocytes. Immunohistochemical studies showed that epithelioid cells were focally positive for vimentin, melanocytic markers (HMB-45), myoid markers (α-smooth muscle actin), CD34 and CD68; negative for cytokeratin, epithelial membrane antigen, CD10, and S-100. And the Ki67 index showed approximately 3%. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML and discuss its diagnosis, differential diagnosis and the prognosis.     

Composite renal cell carcinoma and angiomyolipoma: a study of the histogenetic relationship of the two lesions

The purpose of the present study was to investigate the possible histogenetic relationship of renal cell carcinoma (RCC) and angiomyolipoma (AMYL) occurring in the same renal nodule by examining two cases of composite RCC and AMYL in patients without stigmata of tuberous sclerosis and by reviewing the medical literature of similar cases. Case 1 represents an epithelioid variant of AMYL with multiple additional nodules of typical AMYL in a surgically removed kidney. The patient subsequently developed a lesion consisting of a mixture of epithelioid variant of AMYL and RCC 24 months later in the retroperitoneum and, an additional 4 months later, in the liver. The RCC cells resembled mononucleated epithelioid cells of the epithelioid AMYL except that they were focally reactive with epithelial membrane antigen (EMA) in the retroperitoneum and focally reactive with both EMA and cytokeratin (CK) in the liver. Case 2 consisted of a typical AMYL admixed with a chromophil cell RCC. A review of the medical literature revealed seven additional cases with histopathological findings similar to this case. All cases had multiple foci of typical AMYL. Immunostaining results are available in five tumors. Chromophil RCC showed variable reactivity with CK and EMA. In addition, RCC in the two cases in the present study also displayed a positive reaction with mucin staining and a positive reactivity with carcinoembryonic antigen. There appears to be a spectrum of histopathological and immunohistochemical changes from the epithelioid variant of AMYL through a mixed epithelioid AMYL/RCC to chromophil RCC in three successive specimens in case 1. Moreover, the intimate admixture of AMYL and RCC and the similar expression of epithelial markers of RCC in the two cases in the present study, as well as other cases in the literature, suggest that some RCC develop from the same precursor cell as AMYL or from a component of AMYL.     

Triple synchronous neoplasms in one kidney: report of a case and review of the literature

We report the case of a patient with three synchronous but histologically different primary renal tumors that were all in the same kidney. Two tumors were different subtypes of renal cell carcinoma (RCC), and the third was a variant form of angiomyolipoma. The patient was a 62-year-old man who was receiving antihypertensive drugs and came to our hospital for a regular check-up. Ultrasonography performed during the visit revealed a left renal mass, but the patient had no related symptoms. Subsequent computed tomography revealed two round, high-density masses, one in the mid-portion and the other in the lower pole of the left kidney, and multiple cysts in the right kidney and the liver. The mass in the mid-portion measured 3.3 x 3.0 x 2.8 cm, and the mass in the lower pole measured 1.7 x 1.1 x 0.9 cm. A left radical nephrectomy was performed. On gross examination, an additional ovoid nodule (0.6 cm in the greatest dimension) was found in the lower pole. Microscopically, the largest tumor consisted of a broad alveolar arrangement of large round cells with abundant eosinophilic or clear cytoplasm, distinct cell borders, and perinuclear halos, features consistent with chromophobe RCC. The smallest tumor was a conventional (clear-cell) RCC. The third tumor was composed solely of atypical epithelioid cells with prominent nucleoli and yellowish-brown to black pigments. The tumor cells were positive for melanin (Fontana-Masson stain), the melanoma marker HMB45, vimentin, smooth-muscle actin, and the macrophage marker CD68 and were negative for cytokeratin. This tumor was considered a pigmented epithelioid type of angiomyolipoma. The histologic, histochemical, and immunohistochemical features in this case confirmed the presence of three synchronous primary tumors, a chromophobe and a clear-cell type RCC and a pigmented epithelioid angiomyolipoma, all of which were in the same kidney. This case is the first of its type reported in the literature.     

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。     

Fine-needle aspiration cytology of renal angiomyolipoma: Report of a case with immunocytochemical and electron microscopic findings

A case is presented in which the diagnosis of renal angiomyolipoma was made by computed tomography (CT)-guided, fine-needle aspiration cytology and the examination of a cell block. The tumor was characterized by epithelioid smooth muscle cells, blood vessels and fat in the cytologic material. The cytodiagnosis was further substantiated by positive staining of the epithelioid muscle cells for markers of muscle-specific actin, HMB45, and trace positivity for vimentin but not with S100 protein, desmin, or cytokeratin. Further studies for the recently described crystalloids were also performed by using the periodic-acid Schiff stain with and without diastase treatment and electron microscopy on the cytologic material. However, no such crystalloids were found. A preoperative cytologic diagnosis of renal angiomyolipoma was considered to be of value due to the difference in management between angiomyolipoma and a renal carcinoma, both of which can present as a renal mass on imaging. Diagn. Cytopathol. 1998;18:297–300. © 1998 Wiley-Liss, Inc.     

Multifocal and microscopic chromophobe renal cell carcinomatous lesions associated with ‘capsulomas’ without FCLN gene abnormality

Chromophobe renal cell carcinoma (RCC) accounts for approximately 5% of renal epithelial neoplasms. Multiple and/or bilateral chromophobe RCCs in an individual are generally rare but frequently occur in patients with Birt–Hogg–Dubé syndrome (BHDS) and in patients with tuberous sclerosis complex (TSC). The responsible genes in both BHDS and TSC act as tumor suppressors. Therefore, it seems that some genetic backgrounds are required for the generation and progression of multiple chromophobe RCCs. Here, we report a case of multiple and bilateral chromophobe RCCs along with several small‐sized capsular angiomyolipomas known as ‘capsulomas’ in a 39‐year‐old woman who had neither a particular medical history nor specific gene mutation. There has been no report of sporadic multiple chromophobe RCCs and ‘capsulomas’ developing in a patient without genetic features, having potential for novel genetic variation.     

Minute perivascular epithelioid cell (PEC) nests in the abdominal lymph nodes—a putative precursor of PEComa

A perivascular epithelioid cell tumor (PEComa) is a peculiar growth defined as a mesenchymal tumor composed of histologically and immunohistochemically distinct perivascular epithelioid cells (PECs). Because neither normal counterparts nor precursor lesions of PEComa have been identified, we examined minute PEC nests, ranged from 0.8 mm to 10 mm, to investigate the possible origin of the PEComa. We examined a total of 80 677 para‐aortic and pelvic lymph nodes that were systematically dissected from 1656 patients for gynecological malignancies. The identified lesions were confirmed immunohistochemically with multiple PEC markers, including smooth muscle actin, HMB45, melan‐A, MiTF, ER and PgR. A total of 66 minute PEC nests were found in 21 patients (1.3% of the total population) with an average frequency of 3.1 lesions per patient. In cases of multiple involvement, 11 of 13 nests were located at the same level of multiple lymph node or on continuous levels. The lesions were preferentially distributed at the level of para‐aortic and high pelvic lymph nodes. All nests were positive for actin and HMB45, whereas the other markers were positive with varying frequencies. The minute PEC nests may be associated with the possible normal counterpart of PEComas.     

Xp11.2 translocation renal neoplasm with features of TFE3 rearrangement associated renal cell carcinoma and Xp11 translocation renal mesenchymal tumor with melanocytic differentiation harboring NONO-TFE3 fusion gene

Xp11.2 translocation/TFE3 rearrangement-associated renal cell carcinoma (RCC) and Xp11 translocation renal mesenchymal tumor are distinct tumor entity. To broaden the spectrum of Xp11 neoplasms, we investigated a novel tumor exhibiting morphologies overlapping Xp11.2 translocation/TFE3 rearrangement-associated RCC and the mesenchymal counterpart with melanocytic differentiation by immunohistochemistry, fluorescence in situ hybridization (FISH) and RNA sequencing, as well as literature review. Histologically, the tumor was composed of three different types of tumor cells, including a large proportion of clear cells, small round cells, and a few spindle cells, presenting a relatively clear border in the majority area. The nuclei of all tumor cells showed extensively and strong positive expressions of TFE3. Whereas, the clear cells positively expressed the RCC-related markers including PAX8, RCC marker and CD10, and negatively expressed HMB45; On the contrary, the small round cells and spindle cells positively expressed melanocytic marker HMB45, and negatively expressed PAX8, RCC marker and CD10. The ki67 index was higher in the small round cells and spindle cells than that in the clear cells. FISH revealed the rearrangement of TFE3 gene in all the three types of cells. The NONO-TFE3 fusion gene was detected in all tumor cells by RNA sequencing. This unique Xp11 translocation-associated neoplasm might represent a distinct entity overlapping Xp11 translocation RCC and the mesenchymal counterpart with melanocytic differentiation, broadening the spectrum of Xp11 neoplasms. The patient died of tumor recurrence and lung metastasis after seven months after the surgery suggesting those tumors have an unfavorable prognosis.     

肾脏上皮样色素性透明细胞肿瘤病理形态观察

目的 探讨上皮样色素性透明细胞肾脏肿瘤形态学特点,加强对该肿瘤的认识,减少误诊.方法 回顾性分析2000余例肾脏肿瘤,符合上皮样色素性透明细胞肿瘤3例,通过HE、免疫组织化学EnVision法观察3例肿瘤形态学特点,对其中1例行超微结构观察,同时复习相关文献.结果 女性2例,男性1例,2例形态学表现为透明细胞癌样,1例见透明细胞和嗜酸性细胞构成乳头结构.免疫组织化学上皮标记及S-100蛋白均为阴性,HMB45均为阳性,2例Melan A阳性.电镜末见黑色素小体结构.结论 色素性透明细胞上皮样肿瘤是非常罕见的肾脏肿瘤,病理学特征兼有肾细胞癌、上皮样血管平滑肌脂肪瘤与黑色素瘤等肿瘤特征,免疫组织化学有利于鉴别诊断.其可能是上皮样血管平滑肌脂肪瘤的一种亚型.     

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.     

伴有TFE3扩增的肾脏上皮样血管平滑肌脂肪瘤

目的探讨伴有TFE3扩增的肾脏上皮样血管平滑肌脂肪瘤(epithelioid angiomyolipoma,EAML)的病理学特征、鉴别诊断及生物学行为。方法对1例伴有TFE3扩增的肾脏EAML进行组织形态学观察、免疫组化染色及荧光原位杂交(fluores-cence in situ hybridization,FISH)检测,追踪随访患者预后,并复习相关文献。结果该例EAML呈片状弥漫分布,瘤细胞呈上皮样改变,细胞形态异型性较大,核分裂象易见。肿瘤侵犯包膜。瘤细胞表达SMA、TFE3、cathepsin K,TFE3基因出现多倍体扩增,未见易位发生。患者第一次手术3个月后肿瘤复发,术后半年腹腔肿瘤广泛侵犯、肺部见转移。结论伴有TFE3扩增的EAML组织学形态及生长方式更具恶性特征,预后更差,与经典型EAML有所不同,需与其他形态学相似的肿瘤相鉴别。     

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.     

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.     

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。