Pathology Department, University Hospital Virgen Macarena, Seville, Spain.
School of Medicine, University of Seville, Seville, Spain.
Oncotarget. 2022 Feb 17;13:387-392. doi: 10.18632/oncotarget.28192. eCollection 2022.
Metanephric adenoma (MA) is an uncommon benign tumor accounting for 0.2-0.7% of adult renal epithelial neoplasms. The clinical course is often indolent, but diagnosis should not be delayed since clinical symptoms (hematuria, fever, palpable abdominal mass, and flank pain) may be non-specific and overlap with those of a malign renal neoplasm. We report on 4 cases of AM, for which morphological and mutational analysis were performed.
Immunohistochemical staining was performed on sections cut from paraffin blocks to assess expression of WT1, vimentin, racemase, CK7, CD10 and RCC. Testing for the BRAF gene mutation V600 was carried out using real-time PCR (Cobas 4800).
In all four cases, tumors were visible as well-circumscribed, non-encapsulated masses located in the renal cortex and extending towards the medulla. At immunohistochemical examination, tumor cells stained negative for CK7, CD10 and RCC and positive for both WT1 (nuclear, intense) and vimentin (cytoplasmic, intense, and diffuse). Molecular analysis revealed the BRAF gene mutation V600E in three cases and wild-type BRAF in the fourth.
BRAF molecular mutation analysis may aid diagnosis in cases with atypical histological features, especially in small incisional biopsies when reassessment of surgical treatment may be considered.
后肾腺瘤（MA）是一种罕见的良性肿瘤，占成人肾上皮性肿瘤的 0.2-0.7%。其临床病程通常较为惰性，但由于临床症状（血尿、发热、可触及的腹部肿块和腰痛）可能不具特异性且与恶性肾肿瘤重叠，因此不应延误诊断。我们报告了 4 例 MA 的病例，对其进行了形态学和突变分析。
对石蜡块切片进行免疫组织化学染色，以评估 WT1、波形蛋白、racemase、CK7、CD10 和 RCC 的表达。使用实时 PCR（Cobas 4800）检测 BRAF 基因 V600 突变。
在所有 4 例病例中，肿瘤均为边界清楚、无包膜的肿块，位于肾皮质并向髓质延伸。免疫组化检查显示，肿瘤细胞 CK7、CD10 和 RCC 均为阴性，WT1（核，强阳性）和波形蛋白（细胞质，强阳性，弥漫性）均为阳性。分子分析显示 3 例存在 BRAF 基因 V600E 突变，而第 4 例为野生型 BRAF。
在具有非典型组织学特征的病例中，BRAF 分子突变分析可能有助于诊断，特别是在需要重新评估手术治疗的小切取活检中。
