Case 30

A 30-year-old female with a right kidney tumor.

1. What's the morphology impression?

   A: Papillary renal cell carcinoma

   B: TFEB-rearranged renal cell carcinoma

   C: Adenoid cystic carcinoma

   D: Mucinous tubular and spindle cell carcinoma

   E: Clear cell carcinoma with mucinous differentiation

Answer

This is a case of mucinous tubular and spindle cell carcinoma. Densely arranged, elongated, interconnected tubules lined by low-grade cuboidal cells transitioning into bland spindle cells within a myxoid stroma enriched with basophilic extracellular mucin. Tumors are positive for PAX8, CK7, AMACR. Molecularly, there are multiple chromosome loss and VSTM2A RNA expression by in situ hybridization.

References: https://tumourclassification.iarc.who.int/chaptercontent/36/8

Case credit: UCSD Pathology

Author: Wangpan Jackson Shi, MD