Renal cell carcinoma (RCC), not otherwise specified (NOS) is a tumor that cannot be readily classified into one of the known RCC subtypes. RCC NOS has also been referred to as RCC, Unclassified type and can account for up 10% of RCCs.  RCCs, NOS are morphologically and immunophenotypically heterogeneous, can vary from low grade to high grade tumor with variable outcomes.  Exclusions of other RCC subtypes with immunohistochemistry and molecular workup (if possible) are needed before defaulting to this diagnosis.  ^1-4