A MEST up classification? Review of the re-classification of mixed epithelial and stromal tumor and adult cystic nephroma for the abdominal radiologist.

Mixed epithelial and stromal tumor (MEST) and the tumor formerly known as adult cystic nephroma (ACN) are uncommon renal tumors that have historically been described as separate entities in terms of histologic and imaging findings. However, these entities share many epidemiologic, radiologic, and pathologic features. While recent surgical and pathological literature has supported classifying MEST and ACN within the same tumor family, most radiologists and radiology texts continue to describe MEST and ACN as separate entities.