Atypical metanephric adenoma - A case report and review of literature

Department of Pathology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, UP, India.
International Urology and Nephrology (Impact Factor: 1.52). 02/2007; 39(1):123-7. DOI: 10.1007/s11255-005-4970-y
Source: PubMed


Metanephric adenoma (MA) is a rare renal neoplasm that generally occurs in adults and is considered to have a good prognosis. However, one case of MA with atypical histological features and distant metastasis and another case of metastasizing MA with typical cytologic features have been reported. The authors here report a case of MA with atypical histological features arising in the left kidney of an 18-year-old girl presenting with painless hematuria. Relevant literature is reviewed and discussed.

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    ABSTRACT: Metanephric adenoma (MA) is a renal tumor that is rarely diagnosed in children. Although it is considered benign and to have a good prognosis, the diagnosis of MA is challenging because of histopathologic and radiologic similarities to Wilms tumor. In this case report, we present a 6-year-old girl, with a renal mass and right hemihypertrophy, who was previously diagnosed as Wilms tumor on a fine-needle biopsy and diagnosed as MA after nephroureterectomy. The differentiation between Wilms tumor and metanephric adenoma is also discussed.
    Journal of Pediatric Hematology/Oncology 07/2009; 31(6):453-5. DOI:10.1097/MPH.0b013e31819e8f72 · 0.90 Impact Factor
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    ABSTRACT: SUMMARY: Renal metanephric adenoma (MA) is an extremely rare benign tumor, especially in children under the age of 12 years old. In this article, we report a case of MA that was incidentally discovered in a 2-year-old girl by ultrasound. Magnetic resonance scan revealed a mass of right kidney that was hypointense and hyperintense on T1- and T2-weighted images, respectively. Laparoscopic nephron-sparing surgery was carried out to remove the lesion. Histopathologic examination of the specimen revealed MA with clear surgical margins. Immunohistochemically, the tumor cells showed focal reactivity for CD56, pan-cytokeratin (AE1/AE3), and epithelial membrane antigen, and negative reactivity for Wilms' tumor 1 gene product. Meanwhile, the tumor stroma was diffusely positive for vimentin. We also review the literature regarding the clinical, imaging, and histopathologic features of this lesion in the pediatric population.
    Journal of Pediatric Hematology/Oncology 08/2010; 32(6):489-93. DOI:10.1097/MPH.0b013e3181e34de1 · 0.90 Impact Factor
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    ABSTRACT: Aims: To evaluate morphological and immunohistochemical (IHC) features helpful in distinguishing metanephric adenoma (MA) from solid papillary renal cell carcinoma (s-PRCC). Methods and results: We present a detailed study of 21 MA and 23 s-PRCC. The two entities exhibited significant similarities, both being well-circumscribed tumours composed of tightly packed small cells arranged in solid sheets or ill-defined tubules, often presenting glomeruloid bodies, psammoma bodies and dystrophic calcification, and showing overlapping immunoreactivity for S100, CD57 and CK7. Conversely, most MA were non-encapsulated, whereas most s-PRCC showed a thick fibrous pseudocapsule; MA cells had scanty cytoplasm and a high nuclear:cytoplasmic ratio in comparison to s-PRCC, where occasional tumour cells showed abundant cytoplasm and high nuclear grade. Polypoid branching fronds were common in MA, but absent in s-PRCC; multifocality and papillary hyperplasia/adenoma were seen only in s-PRCC. MA were positive for WT1 and negative for EMA and alpha-methylacyl-CoA racemase (AMACR); s-PRCC were positive for EMA and AMACR and negative for WT1. Conclusions: Despite overlapping features, careful morphological and architectural evaluation should result in accurate diagnosis of most MA and s-PRCC. In challenging cases, IHC stains for WT1, EMA and AMACR may help in distinguishing these two entities.
    Histopathology 02/2013; 62(6). DOI:10.1111/his.12106 · 3.45 Impact Factor
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