Clinicopathological analysis of 156 patients with angiomyolipoma originating from different organs

Abstract

Abstract. Angiomyolipoma (AML) is a benign mesenchymal tumor composed of variable proportions of adipose tissue, spindle and epithelioid smooth muscle cells and abnormal thick-walled blood vessels. Approximately one-third of epithelioid AML (EAML) cases have been reported to have metastasis. Thus, it would be of interest to identify the adverse pathological parameters correlated with outcome. However, few studies have been conducted on large numbers of samples. The aim of this study was to highlight the clinicopathological features of AML and the morphological features of EAML, which were correlated with malignant behaviors in patients from a single institutional series analysis. One hundred and fifty-six consecutive AMLs, correlating with pathological characteristics, were analyzed between 1981 and 2010. The Chi-square test was performed to clarify the significance of the clinicopathological factors among the regular and epithelioid subtypes with or without atypia. The two organs most commonly involved were the kidney (77%, 120/156) and liver (14%, 22/156). Of the 156 AMLs, EAMLs (17.3%, 27/156) had more marked mitosis, hemorrhage and multinucleated giant cells compared with the regular AMLs (82.7%, 129/156). The 11 EAMLs with atypia (40.7%, 11/27) had more nucleoli and mitotic cells compared with the 16 EAMLs without atypia (59.3%, 16/27; p<0.05). Follow-up results of 79% of cases (124/156) were obtained, and of these, only one kidney AML (0.8%, 1/124) presented with liver metastasis one year after nephrectomy. This sizeable single institutional AML series analysis revealed that the kidney and liver were the two most commonly involved organs, and most of the cases presented a benign clinical course. Few EAMLs were malignant, although adverse features including atypical mitotic figures, blood vessel invasion and tumor embolus may be significant in predicting malignant behavior. IntroductionAngiomyolipoma (AML) is a relatively rare neoplasm, composed of variable proportions of adipose tissue, spindle and epithelioid smooth muscle-like cells and abnormal thick-walled blood vessels (1). Most AMLs are regarded as benign in clinical course, although certain cases have been reported to be recurrent or metastatic. Approximately 30% of epithelioid AMLs (EAMLs), which are partially or entirely composed of large epithelioid cells with abundant cytoplasm, vesicular nuclei and prominent nucleoli, have malignant potential (2). By contrast, an epithelioid morphology of the smooth muscle-like cells has been described in regular AMLs that are not associated with aggressive clinical behavior. This is analogous to the conventional description of smooth muscle neoplasm, in which epithelioid and conventional spindle cell leiomyomas exist; when referring to smooth muscle neoplasms, ʻepithelioidʼ does not necessarily indicate atypia or increased risk of malignancy (2). Therefore, in 2010, Brimo et al proposed the concept of atypical EAMLs, and suggested that although not all EAMLs have malignant potential, certain atypical morpholog...

Angiomyolipoma of the kidney: Clinicopathological and immunohistochemical study

“…This finding was consistent with previously published studies [5,9]. However, Yang et al [1] reported that female: male ratio was 2:1.…”

“…Concomitant finding was previously reported [1,5,9]. Martignoni et al stated that the mean age at diagnosis of AML in surgical series is between 45and 55 for patients without TS [9].…”

“…This finding is in keeping with those of Varma et al [8], who also stated that classic renal angiomyolipomas may have locoregional or multicentric involvement; however, these lesions have always behaved in a benign manner and have not been associated with an adverse prognosis. Similarly, Yang et al [1] in their study found that 6/122 of the classic renal AML cases presented with multiple foci. Two of the cases had foci located in the bilateral kidney as well.…”

“…Angiomyolipoma belongs to a family of neoplasms called perivascular epithelioid cell tumors (PEComas) [1][2][3][4][5][6][7][8]. The World Health Organization (WHO) defines PEComas as ''mesenchymal tumors composed of histologically, ultra structurally, and immunohistochemically distinctive perivascular epithelioid cells C [9].…”

Estudo mutacional em pacientes com o complexo da esclerose tuberosa

“…Esses tumores são observados mais frequentemente em rins, podendo ocorrer em outros órgãos, como por exemplo, fígado, glândula adrenal, pâncreas e pelve (Crundwell, 2004;Orlova & Crino, 2010;Yang et al, 2012;Northrup et al, 2013). Embora grande parte dos pacientes com AML seja assintomática (Folpe & Kwiatkowski, 2010), há risco de sangramento local, causando dor devido ao rompimento de aneurismas do tumor ou compressão e/ou invasão do parênquima renal.…”