Cutaneous metastasis of hepatocellular carcinoma diagnosed by fine needle aspiration cytology and Hep Par 1 immunopositivity

Cutaneous metastasis of hepatocellular carcinoma (HCC) is very rare, accounting for less than 0.8% of all known cutaneous metastases and occurring in 2.7-3.4% of HCCs. With less than 50 such cases reported worldwide, most of which were diagnosed histologically on excised lesions, it can only be expected that diagnosis made on cytological features alone would be challenging. We report a case of cutaneous metastasis of HCC diagnosed based on cytological features and confirmed by Hep Par 1 immunopositivity of the cell block material. An 81-year-old man, who was known to have unresectable HCC, presented with a 1-month history of painless, left nasal alae mass. The mass measured 1.5 cm in diameter, and was multilobulated with a central necrosis. Fine needle aspiration of the mass was done. Smears were cellular, comprising of malignant cells in loose clusters and aggregates as well as singly dispersed. The malignant cells displayed moderate nuclear pleomorphism, occasional prominent nucleoli, and intranuclear pseudoinclusion. Cell block material demonstrated the trabeculae pattern of the malignant cells and Hep Par 1 immunopositivity. The final diagnosis of a metastatic cutaneous HCC was made. In conclusion, cutaneous HCC metastasis is rare and should be considered in the differential diagnosis in patients with a history of HCC presenting with suspicious skin lesion. In the right clinical setting, a confident diagnosis can be made in such cases by using the fine needle aspiration technique aided with immunopositivity for Hep Par 1 antibody of the aspirated material.