Metastatic clear cell carcinoma
Sorry, that is
The correct diagnosis is:
Hepatocellular carcinoma, clear cell variant
- The smears contain a monomorphous population of polygonal cells with prominent nucleoli and clear cytoplasm arranged in broad trabeculae.
- Histochemical stain (PAS plus diastase) confirms cytoplasmic glycogen.
- Immunohistochemical stains for epithelial antigens (CAM 5.2, AE1/AE3) are positive. Polyclonal CEA reveals a canalicular stain pattern. AFP is negative.
- The cytologic features and special stains are consistent with hepatocellular carcinoma, and suggest the clear cell variant.
- The two major types of primary carcinoma of the liver are hepatocellular carcinoma and cholangiocarcinoma (arising from bile duct epithelium). Hepatocellular carcinoma accounts for more than 90% of all primary liver carcinomas. The clear cell variant is rare (approximately 5-10% of cases are of the clear cell variety and are usually mixed with classic HCC cells)
- Fine needle aspirates usually show malignant polygonal cells with central nuclei and abundant clear to finely vacuolated cytoplasm.
- Cells are arranged in cohesive clusters or occur singly.
- Cytoplasmic glycogen gives cells the 'clear' look. Fat may also be present.
- A canalicular staining pattern with polyclonal CEA is useful is helpful in distinguishing primary clear cell HCC from other clear cell malignancies.
- Glycogen or fat in the cytoplasm pushes keratin filaments to the periphery of the cell, as identified with the peripheral cytokeratin (AE1/AE3) staining.
- A number of clear cell tumours may arise from other organs. Most are uncommon except renal cell carcinoma. The importance of clinical history cannot be overemphasised. Important features of metastatic adenocarcinoma are columnar cells with eccentric nuclei, evidence of acinar formation or mucin production.
- Cholangiocarcinomas typically demonstrate glandular or papillary growths pattern and are negative for glycogen and fat stains.
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DeMay RM. The Art & Science of Cytopathology. Chicago: ASCP Press, 1996.