Use of Albumin In Situ Hybridization to Diagnose Cutaneous Metastatic Hepatocellular Carcinoma With Poorly Differentiated Features: A Case Report and Review of the Literature.

Abstract: Hepatocellular carcinoma (HCC) rarely metastasizes to the skin. When it occurs, it is often poorly differentiated making the diagnosis challenging. There exists a male predominance, and clinical presentation usually includes papules or nodules resembling pyogenic granulomas or dermal deposits. Histopathology shows malignant dermal cells. Hepatoid features including nests or cords of cells arranged in a trabecular or pseudoglandular pattern, sinusoidal formation, or the presence of bile exist in less than 50% of cases. Limitations exist with immunohistochemical staining, particularly in poorly differentiated neoplasms. Albumin in situ hybridization is more sensitive for detecting poorly differentiated HCC. Immunostaining in conjugation with albumin in situ hybridization enhances the detection of metastatic hepatocellular carcinoma. We report the case of a 74-year-old man with a history of HCC and a stable lung metastasis who presented with painful, growing bumps on his nose for 2 months. Examination revealed multiple, pink to white, shiny dermal-based papules with telangiectasias involving the right nasal tip and naris. Alpha-fetoprotein level was markedly elevated. Computed tomography showed expanding right lower lobe lung nodules. Histopathology of the cutaneous biopsy revealed features of a poorly differentiated basaloid carcinoma. Immunohistochemical staining was diffusely positive for glypican-3, focally positive for arginase-1, and negative for hepatocyte paraffin 1. Albumin in situ hybridization was diffusely positive, clinching the diagnosis of HCC. Metastatic HCC is a rare encounter for dermatopathologists. We aim to increase awareness of its occurrence in patients with advanced HCC and highlight the importance of clinical correlation when faced with poorly differentiated or unusual-looking basaloid neoplasms.