Cytological features of fibrolamellar variant of hepatocellular carcinoma with review of literature

Significance of hepatocyte atypia in liver fine needle aspiration

Fine needle aspiration (FNA) of the liver is frequently the diagnostic procedure of choice for sampling hepatic lesions. One of the main diagnostic challenges in the interpretation of liver FNA is distinguishing dysplastic lesions and well-differentiated hepatocellular carcinoma (WD-HCC) from benign processes, as they share significant cytomorphologic overlap. Furthermore, the diagnosis of HCC often requires evaluation of stroma for invasion, which may not be present on cytology and small needle biopsy specimens. A reporting system for liver cytopathology has yet to be instituted. Without standardized and well-defined criteria for hepatocyte atypia, we recommend limiting the use of atypia in evaluation of liver FNA specimens to describe a diagnosis of exclusion, in which all known benign and neoplastic processes have been ruled out. The cytologic findings on the FNA of a liver nodule may be best reported as atypical hepatocytes in the absence of a core needle biopsy or cell block sufficient to render a definitive diagnosis of HCC.

Diagnosis of metastatic fibrolamellar hepatocellular carcinoma by endoscopic ultrasound-guided fine needle aspiration

The fibrolamellar variant of hepatocellular carcinoma (FL-HCC) is distinguished from other hepatocellular carcinomas (HCC) by its unique clinical and pathologic features. Cytological features for this tumor on fine needle aspiration (FNA) of primary tumors have been described earlier. We present here a unique case of metastatic FL-HCC diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of mediastinal adenopathy. A 32-year-old woman with a history of oral contraceptive use presented with nausea and severe abdominal pain but no ascites or stigmata of cirrhosis. She had a past history of resection of a liver lesion. Serial computed tomography scans revealed mediastinal lymphadenopathy and the patient was referred for endoscopic ultrasound (EUS). A transesophageal EUS-FNA was performed and tissue was collected for cytological evaluation by an on-site pathologist with no knowledge of prior history. Based on morphology correlated with prior history received later, a final diagnosis of metastatic FL-HCC in the retrocardiac lymph node was rendered on the EUS-FNA samples. There are very few reports in the literature where a diagnosis of FL-HCC is rendered at unusual sites. This case highlights that EUS-FNA is a relatively non-invasive, rapid, accurate and effective modality in obtaining tissue from otherwise hard-to-reach areas. It also suggests that metastasis of FL-HCC can be observed in mediastinal nodes and that diagnosis based on cytological features can be rendered even when the tumor is identified at unusual locations.