Medium power: DQ stain
Large malignant cells of renal cell carcinoma in a background of histiocytes and inflammatory cells
Note the prominent nucleolus and vacuolated cytoplasm
Medium power: DQ stain
Large malignant cells of renal cell carcinoma in a background of histiocytes and inflammatory cells
Note the prominent nucleolus and vacuolated cytoplasm
High power: Pap stain
Metastatic renal cell carcinoma with pleomorphic large cells, enlarged irregular nuclei, coarse chromatin and prominent nucleoli
High power: Pap stain
Metastatic renal cell carcinoma
Note slightly eccentric, enlarged nuclei, prominent nucleoli, and vacuolated cytoplasm
IHC for Pax8 positive in tumor cells
Features
• Most common cause of malignant effusions with adenocarcinomas being the most frequent.
• Foreign population of cells that stand out from mesothelial cells and histiocytes
• Exception:
- cells that mimic native cells
- all tumor cells so they all look alike
• Carcinomas typically form cohesive clusters and ball up to form spheres with smooth community borders ; however some tumors shed as single cells (lobular breast carcinoma, gastric signet ring cells). May or may not have malignant features (enlarged irregular nuclei with pleomorphism) but usually have high N:C ratios and coarse chromatin.
• Large malignant cells
• Abundant vacuolated cytoplasm
• May have granular cytoplasm
• Enlarged round nuclei
• Prominent nucleoli
• IHC: Tumor cells typically express Pax-8, RCC, CD10, cytokeratin while negative for calretinin (D/D mesothelial cells) and CD68 or CD163 (histiocytes)