Abstract

The differential diagnoses of space occupying lesions (SOL) of the liver are wide. It ranges from infectious and inflammatory processes to benign and malignant liver lesions which include primary and metastatic tumors. As the clinical, biochemical and imaging modalities have limitations in the accurate diagnosis, fine needle aspiration cytology places an important role in the categorization of liver SOL. The diagnostic difficulties encountered in FNAC are reduced by the use of cell block preparation and immunohistochemistry.

Aims and Objectives: To evaluate the spectrum of liver lesions, to study the cytological features of SOL of the liver and to evaluate the role of cell block preparation and immunohistochemistry in the diagnosis.

Materials and Methods: Retrospective review of the FNA slides of hepatic lesions during a period of three years from 2014 to 2016 was performed. The slides were studied for detailed cytological features and categorized into adequate, inadequate and inconclusive. The usefulness of cell block preparation and immunohistochemistry in the diagnosis were evaluated.

Results: A total of 638 liver aspirations were evaluated. 438 were adequate, 69 were inadequate and 131 were inconclusive. The age of the patients ranged from 0 to 88 years. Among the 438 adequate aspirations, 301 were metastatic. 250 cases were metastatic adenocarcinoma. Metastasis from squamous cell carcinoma, small cell carcinoma, neuroendocrine tumor, neuroblastoma, gastrointestinal stromal tumor and sarcoma were also encountered. There were 98 cases of hepatocellular carcinoma. Trabecular growth pattern, endothelial cuffing, macronucleoli, multinucleation and intranuclear inclusions were the most frequent findings in HCC. Cell block preparation was done in 107 cases. In nine cases, where the FNA was inconclusive, cell block preparation alone helped in making morphological diagnosis thus avoiding the need for a repeat procedure. IHC was done in cell block preparation of 66 cases which helped in the differentiation between well differentiated HCC from benign hepatic proliferations and poorly differentiated HCC from metastatic adenocarcinoma, to know the primary site of metastatic adenocarcinoma and to diagnose uncommon tumors.

Conclusion:  In this study, we had a wide spectrum of liver lesions. The main diagnostic difficulties encountered were to differentiate well differentiated HCC from benign hepatic proliferations and poorly differentiated HCC from metastatic adenocarcinoma.  Detailed cytological evaluation along with cell block preparation and subsequent IHC helped in the diagnosis.

Keywords: cell block, fine needle aspiration cytology, immunohistochemistry, liver lesions