Renal cell carcinomas with intratumoral fat and concomitant angiomyolipoma: Potential pitfalls in staging and diagnosis

Manju Aron, Hakan Aydin, Linda Sercia, Cristina Magi-Galluzzi, Ming Zhou

Research output: Contribution to journalArticle

10 Scopus citations


Intratumoral fat and angiomyolipomas (AMLs) occurring within renal cell carcinomas (RCCs) have rarely been reported but may be mistaken for tumor invasion into perinephric or renal sinus fat or misdiagnosed as tumor exhibiting sarcomatoid differentiation. We report 16 such cases. In 14 RCC cases, there was intratumoral fat, 9 of which had fat located peripherally near the capsule (n = 6), renal sinus (n = 1), or both (n = 2). Inflammatory infiltrates and osseous metaplasia were identified in the intratumoral fat in 7 and 8 cases, respectively. Two cases had intratumoral AML foci located at the periphery of RCC. Intratumoral fat or AML at the periphery of RCC simulated the invasion into the fat, while the smooth muscle component of AML resembled spindle cell, or sarcomatoid, differentiation. Our study highlights the potential pitfalls in staging and diagnosis when intratumoral fat or AML is found within RCC.

Original languageEnglish (US)
Pages (from-to)807-812
Number of pages6
JournalAmerican journal of clinical pathology
Issue number5
StatePublished - Nov 1 2010



  • Angiomyolipoma
  • Intratumoral fat
  • Renal cell carcinoma

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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