Metanephric adenoma: molecular study and review of the literature

Abstract

Introduction: 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. Material and Methods: 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). Results: 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. Conclusions: 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.

A giant metanephric adenoma in a young male

“…2 . Differential diagnosis includes Wilms’ tumor, renal papillary neoplasms and nephrogenic rests [ 5 ]. MA can be diagnosed using hematoxylin and eosin (H&E) staining, but immunohistochemistry is needed especially when samples are obtained by core needle.…”

Metanephric adenoma of the kidney: clinical case and literature review

“…Молекулярно-генетические исследования позволяют уточнить диагноз в сложных случаях. Большинство зарегистрированных метанефральных аденом демонстрируют отсутствие трисомии хромосом 7 и 17 и потери Y-хромосомы, наличие которых характерно для папиллярного почечно-клеточного рака [22][23][24].…”

“…В серии исследований сообщается о наличии мутации гена BRAF V600E, V600D и V600K в метанефральных аденомах (табл. 2) [9,22,[25][26][27][28][29]. [22] и [25])…”

“…Table 2. BRAF mutation in metanephric adenoma (adapted from [22] and [25]) Большинство метанефральных аденом являются доброкачественными, и редко сообщается об их инвазивном и метастатическом биологическом поведении [5,30]. Лечение метанефральной аденомы остается хирургическим.…”

Metanephric adenoma managed with robotic partial nephrectomy: A case report

“…Metanephric adenomas arise from metanephric cells and are associated with maturing nephroblastomas, or Wilm's tumors (WTs). Reports have described them as being more common in women (2:1) and generally arising in adults age 50-70 [2], although there have been reports of pediatric MAs in children as young as 15 months [3]. Metanephric adenomas are benign and have a favorable prognosis [4].…”