CA9 and neoplasm: Upon closer inspection, it appears TSC-associated PRCC and RCC-LMS/RAT neoplasms described in TSC show overlapping morphological and immunophenotypic features including abundant clear cytoplasm of tumor cells which show a predominantly tubulopapillary and solid growth pattern, the presence of a prominent fibromuscular stroma, and positivity for CK7 and CAIX without staining for CD117.