Metanephric adenoma and solid variant of papillary renal cell carcinoma: Common and distinctive features

Mariana Mantoan Padilha, Athanase Billis, Daniela Allende, Ming Zhou, Cristina Magi-Galluzzi

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)941-953
Number of pages13
Issue number6
StatePublished - May 2013


  • Differential diagnosis
  • Immunohistochemistry
  • Metanephric adenoma
  • Solid variant of papillary renal cell carcinoma

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology


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