Hepatoid Adenocarcinoma of Lung Presenting as Soft-tissue Swelling: A Rare Case Report

Hepatoid Adenocarcinoma of the Lung (HAL) is a rare type of Non-Small Cell Lung Cancer (NSCLC), histologically similar to Hepatocellular Carcinoma (HCC). Hepatoid adenocarcinoma presenting as soft-tissue swelling is extremely rare. Less than 40 well-documented cases in the literature have been added to date. Diagnostic work-up included clinical history, Alpha-Fetoprotein (AFP) serum marker level, imaging, histological uniqueness, immunohistochemical expression, and molecular testing. Hepatoid adenocarcinoma of the lung has high malignancy and poor prognosis and needs a better treatment plan. Hence, we report a case of a 73-year-old male presenting with a history of swelling on the right arm for three months. On Magnetic Resonance Imaging (MRI), the soft-tissue swelling radiological features were suggestive of sarcoma. An excisional biopsy was done. Histomorphological and immunohistochemical expression revealing features of metastatic deposits from hepatoid adenocarcinoma of the lung. Patient expired during follow-up. Hepatoid adenocarcinoma of the lung is a special type of NSCLC. The surgical treatment of HAL in the limited stage can achieve long-term survival, but most of them are in the advanced stage when they are found, and the prognosis is poor, which requires multidisciplinary comprehensive treatment.