Malignant monotypic epithelioid angiomyolipoma of the kidney (original) (raw)
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Malignant Epithelioid Angiomyolipoma of the Kidney
Journal of the Formosan Medical Association, 2007
Angiomyolipoma (AML) is a common benign renal tumor that is composed of thick-walled blood vessels, smooth muscle, and adipose tissue, but the malignant epithelioid variant is extremely rare. Here, we report a case of a 78-year-old woman who had malignant epithelioid AML with regional lymph node metastases.
Renal Angiomyolipoma With Epithelioid Sarcomatous Transformation and Metastases
The American Journal of Surgical Pathology, 2000
Angiomyolipoma (AML) is a benign neoplasm that occurs either sporadically or in patients with tuberous sclerosis complex (TSC) and shows frequent allelic losses at chromosome arm 16p. It has been suggested recently that the melanogenesis marker-positive perivascular epithelioid cell (PEC) has been found consistently in AML. The authors report a 50-year-old woman without evidence of TSC affected by classic renal AML containing an area composed of atypical epithelioid cells with the same morphoimmunophenotypic characters of PEC. After 7 years from surgical removal of the lesion, the patient developed a local recurrence and successive lung and abdominal metastases that showed morphologic and immunohistochemical features overlapping those of the epithelioid area of the previously removed AML. Genetic analysis showed that the classic AML and its epithelioid area as well as the pulmonary and abdominal metastases shared the same allelic loss on chromosome arm 16p. Based on these findings, the authors view this case as evidence of a malignant transformation of a classic AML with morphologic, immunophenotypic, and genetic demonstration of its clonal origin.
Clinical presentation of epithelioid angiomyolipoma
International Journal of Urology, 2007
Objective: Epithelioid angiomyolipomas (AML) of the kidney are malignant tumors with aggressive clinical behavior. Methods: We reviewed cases of epithelioid AML recently diagnosed at our institution to highlight the spectrum of clinical presentations. Results: In all cases, renal lesions seen on computed tomography were suspicious for renal cell carcinoma (RCC). Histologically, these tumors can resemble RCC. The diagnosis of epithelioid AML was established by positive staining for melanoma and smooth muscle cell markers, and presence of perivascular epithelioid cells. One patient presented with a renal tumor extending into the inferior vena cava to the level of the hepatic veins. Two patients developed recurrent, metastatic disease following nephrectomy. One patient with tuberous sclerosis and multiple, bilateral AML developed an enhancing renal tumor that did not contain any fat densities. A partial nephrectomy was performed and pathology revealed epithelioid AML adjacent to conventional AML. Conclusions: These tumors are distinguished from RCC by positive immunostaining for melanoma markers and smooth muscle cell markers. They resemble conventional RCC on imaging. Epithelioid AML may be locally aggressive and metastasize.
An unusual appearance of renal epithelioid angiomyolipoma
Singapore medical journal, 2012
Epithelioid angiomyolipoma is a recently described rare variant of renal angiomyolipoma. It can occur in patients with or without tuberous sclerosis. We report the imaging findings of a case of epithelioid angiomyolipoma that showed the presence of fatty tissue undifferentiated from the typical angiomyolipoma at the beginning. After partial nephrectomy, tumour recurrence occurred two years later, presenting as completely solid tumours with no adipose tissue, and with invasion into the psoas muscle and left adrenal gland. Differentiation of this tumour from renal cell carcinoma is difficult. Both the radiologist and surgeon should be aware of the existence of this tumour and its potentially malignant behaviour.
Epithelioid Angiomyolipoma of the Kidney
The American Journal of Surgical Pathology, 1997
Epithelioid angiomyolipoma (eAMLoma) is an uncommon renal mesenchymal tumor with malignant potential and is frequently associated with tuberous sclerosis (TSC). It is composed of polygonal large-sized tumor cells arranged in an epithelioid manner. Differential diagnosis from renal cell carcinoma (RCC) is often challenging because of its epithelioid morphology. Herein is reported three cases of eAMLoma, involving one in a 28-year-old man with TSC and two in women without TSC (34 and 62 years of age, respectively). The male TSC patient had microscopic conventional AMLomas in the same kidney. All patients were positive for melanoma (reactive with HMB45 antibody, and positive for melan A, tyrosinase and microphthalmia transcription factor) and smooth muscle markers (positive for a-smooth muscle-specific actin), but not for epithelial markers (cytokeratin, epithelial membrane antigen). In particular, the translocation RCC is an important differential diagnostic candidate, in terms of the positive reaction with HMB45 and morphological similarity. The present tumor samples did not show any reactivity for transcription factor binding to IGHM enhancer 3 or transcription factor EB, which excluded the possibility of translocation RCC. The possibility of eAMLoma should be evaluated as a diagnostic candidate, especially in cases of renal tumors (i) in young patients; (ii) associated with TSC; or (iii) with an epithelioid morphology and a high nuclear grade.
Massive Malignant Epithelioid Angiomyolipoma of the Kidney
Journal of Kidney Cancer and VHL
Renal angiomyolipomas (AMLs) are a subset of perivascular epithelioid cell neoplasms (PEComas) that are associated with tuberous sclerosis complex (TSC). Epithelioid angiomyolipomas (EAMLs) are a rare variant of AML with more aggressive propensities. EAMLs with malignant potential can be difficult to distinguish from relatively benign AMLs and other renal tumors. Although there are no established criteria for predicting EAML malignancy, there are proposed histologic parameters that are associated with higher tumor risk. EAML can be treated with surgical resection as well as mTOR inhibitors. Here, we present a unique case of a patient with a 36-cm renal EAML metastatic to the lungs that was treated with complete surgical resection of the primary lesion and mTOR inhibition.
Renal Angiomyolipoma (AML) is a benign lesion with a variable admixture of fat cells, thick walled blood vessels, smooth muscle and polygonal epithelioid cells. The lesion can be diagnosed with certainty in the presence of all the components on fine needle aspiration, supported by CT findings. However the presence of predominant population of epithelioid cells with paucity or absence of other components can be particularly worrisome, especially if radiological findings are noncontributory. These large cells with low N:C ratio and frothy cytoplasm and anisonucleosis require detailed evaluation and careful search for typical background cytology. Two such cases of AML with a predominant population of epithelioid cells are being described with their cytological and histological findings with a review of literature to highlight the diagnostic dilemma and emphasize the utility of HMB-45 immunostaining in such cases.