Metastatic hepatocellular carcinoma diagnosed by fine needle aspiration: A clinical and cytologic study

Hepatocellular carcinoma (HCC) is the second leading cause of cancer deaths worldwide. The clinical and cytological features of metastatic HCC have not been well established.

To determine the clinical and cytological features of metastatic HCC, we retrospectively searched for all HCC metastasis diagnosed by fine needle aspiration or core biopsy.

We found 12 bone metastases, 11 intra-abdominal, 4 lung, 3 soft tissue, and 2 lymph node metastases from 32 patients. 7/12 bone metastases were vertebral body, 4 were pelvic bone, and 1 case was humerus. 10/32 cases showed concurrent metastasis at a different location. The average metastasis size was 40.9 mm. Tumor grades of HCC showed near equal distribution. The following cytological features are most frequently associated with metastatic HCC: single tumor cells (88.9%), cytoplasmic vacuolization (70.4%), trabecular pattern (70.4%), bare nuclei (66.7%), prominent nucleoli (66.7%), tumor giant cells (44.4%), and traversing capillaries (44.4%) and encased by endothelium (18.5%). Immunohistochemical stains of 12 cases showed the majority were positive for E-Cadherin, Carcinoembryonic Antigen, and HepPar1. Negativity for CK7 and CK20 is contributory to making the diagnosis.

The most frequent metastatic HCC diagnosed by FNA was from bone, especially the vertebral body. The frequent cytomorphology and immunophenotype seen in primary HCC are good diagnostic criteria for diagnosing metastatic HCC.