A Four-Year Follow-up Study of Renal Epithelioid Angiomyolipoma: A Multi-Center Experience and Literature Review

Abstract

In this study, we systematically explored the clinical manifestations, diagnosis, treatment, and prognosis of renal epithelioid angiomyolipoma (EAML) retrospectively by analyzing data of 52 patients diagnosed with EAML at four centers. Our results showed that the onset of EAML was usually inconspicuous, and so no obvious symptoms or signs had occurred in most patients at diagnosis. Its diagnoses always depended on postoperative pathological examination. The immunohistochemical (IHC) results [HMB45 ( + ), cytokeratin (-), and S100 (-)] could be used to differentiate EAML from other malignancies such as renal cell cancer (RCC) and sarcomas. For treatment, surgery resulted in satisfactory short-term prognosis. The long-term prognosis of patients with EAML was poor, particularly when a large size, a high percentage of epithelioid component, tumor thrombus formation, and necrosis were present. In conclusion, EAML is a tumor with malignant potential. Once diagnosed, integrated approaches, including surgery, chemotherapy, and targeted therapy, should be considered; a close follow-up regimen is necessary for cases that met: 1) tumor size >9 cm, 2) tumor thrombus formation in the vein, 3) epithelioid cells >70% or atypia cells >60%, and 4) necrosis.

Recent Strategies for the Management of Renal Angiomyolipoma: A Review of Diagnostic and Therapeutic Approaches

“…Besides, cytoplasmic periodic acid-Schiff-positive diastase-resistant rhomboid crystals, with no renin immunoreactivity, have been found in renal AML (31). Although the definitive criteria for EAML have not been specified, several large-scale studies have described EAML as follow: large tumor size (> 7 cm), severe cytologic or nuclear atypia, extent of nuclear atypia (≥ 70% atypical epithelioid cells), (extensive) tumor necrosis, large epithelioid cell component, mitotic count (≥ 2 mitosis per 10 high power fields (HPFs)), atypical mitotic figures, lymphovascular invasion, associated TSC or concurrent AML, extrarenal extension and/or renal vein involvement, and carcinoma-like growth patterns (4,26). The presence of 3 or more of these features put the patient at a high risk of clinically malignant EAML.…”

“…Two well-known types have been distinguished including sporadic isolated AML and AML associated with tuberous sclerosis (3). On the other hand, epithelioid AML (EAML) is a potentially malignant mesenchymal neoplasm, which may involve lymph node metastasis and distant metastasis (4). Typically, renal AMLs are variable mixture of 3 mesenchymal constituents: (1) smooth muscle cells, (2) adipose tissue, and (3) blood vessels.…”

An Aggressive Case of Malignant Renal Pecoma Non-Responsive to Motor Inhibition: A Case Report

“…But, looking at the literature there have been several reports of distant metastases after surgical resection of renal PEComas with poor prognosis [4,8]. Even though there was spillage during the initial open surgery, one can't ignore the poor prognostic characteristics of the tumor of size and necrosis [1] and the rapid clinical progression. Although it has been proven that PEComas respond to mTOR inhibition [9,10], it seems that our patient shows no such response and we continue to look for a solution on his behalf.…”

“…A couple of hundred cases are published, with mean age group of approximately 40 years and male to female ratio of 1:1 [1,2]. The perivascular epithelioid cell, or PEC, appears in a certain group of tumors and has it's typical morphological, Immunohistochemical and genetical characteristics [3,4].…”

Renal cell carcinoma: the search for a reliable biomarker

“…Stains to help identify angiomyolipomas include HMB45 and melan-A, which are markers used most frequently to identify melanomas (46,53,54). These markers are also positive in translocation RCCs (46,55).…”