Renal epithelioid angiomyolipoma with malignant features: Histological evaluation and novel immunohistochemical findings

Abstract

Renal epithelioid angiomyolipoma (EAML) is a potentially malignant tumor type whose characteristics and biomarkers predictive of malignant behavior have not been elucidated. Here, we report three cases of renal EAML with malignant features but without histories of tuberous sclerosis complex. Case 1 involved a 29-year-old man with a 12-cm solid mass in the right kidney who underwent radical right nephrectomy. Case 2 involved a 22-year-old woman with a retroperitoneal mass who underwent radical right nephrectomy and retroperitoneal tumorectomy. Local recurrence was detected 7 years post-surgery. Case 3 involved a 23-year-old man with a 14-cm solid mass in the left kidney who underwent radical left nephrectomy. Microscopically, the tumors in all cases demonstrated proliferation of epithelioid cells with atypia, mitotic activity, necrosis, hemorrhage, and vascular invasion. Epithelioid cells in all cases were immunohistochemically positive for melanocytic and myoid markers and weakly positive for E-cadherin and β-catenin. Immunohistochemistry revealed activation of the mammalian target of rapamycin pathway. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML.

Ruptured Hepatic Epithelioid Angiomyolipoma: A Case Report and Literature Review

“…Sometimes, the cells with such expression become epithelioid in morphology. One of the definitions of epithelioid AML in the kidney is that epithelioid cells occupy >10% of the tumor [14]; their membranous positivity for E-cadherin [10] and β-catenin [11] has been documented. In the present case, the epithelioid cell component occupied 50–60% of the tumor, and E-cadherin and β-catenin were weakly positive in a membranous pattern.…”

“…Only a few cases of hepatic epithelioid AML have been reported [3, 9]. Epithelioid AML has been demonstrated to express E-cadherin [10] and β-catenin [11] as well as classical markers of melanocytic and myogenic differentiation such as HMB45 and αSMA. Many cases of ruptured renal AML have been documented in the past [12]; however, ruptured hepatic AML are considered to be extremely rare.…”

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

“…The existing evidence comes for case reports (45). As AMLs, either the TSC or sporadic lymphangioleiomyomatosis, demonstrate mutations in tuberous sclerosis genes, mTOR is activated, and thus, the suppression of this signaling can be regarded as a preemptive treatment (46). Sirolimus known as rapamycin has trialed in TSC patients and come up with tumor regression.…”

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

“…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]. It has been speculated that the PEComa can modulate its morphology and immunophenotype and appear in a spectrum of forms [4,5], making the diagnosis, as in our case, somewhat challenging.…”