Must have low-grade nuclei (Fuhrman grade 2 or lower).
Nuclei are in linear arrangement.
Immunohistochemistry: diffusely CK7+ and AMACR+ like papillary RCC; diffusely CAIX+ like clear cell RCC.
Good prognosis; most reported tumors are low stage (pT1).
Main DDX: (Other tumors with mixed clear cell and papillary architecture)
TFE3 carcinomas: Usually in children or young adults, high-grade cytology and TFE3+.
Tumors with mixed clear cell and papillary tumor with high-grade nuclei lacking linear growth and TFE3-, considered under unclassified RCC.