Abstract Introduction Hepatoid adenocarcinoma is a rare malignant tumor that most commonly arises in the GI tract, pancreas, ovaries, and least often the lung. Hepatoid adenocarcinoma histologically mimics hepatocellular carcinoma but has no primary hepatic lesion. The outcomes for this malignancy are poor with an estimated 3-year survival rate of 14%. Primary hepatoid adenocarcinoma of the lung is even more rare with an estimate of only 5% of cases being primary lung tumors. Hepatoid adenocarcinoma of the lung appears to have a strong male predominance, with an estimated 80% of cases appearing in men. The average age of diagnosis of 60 years, and it is also commonly associated with heavy cigarette smoking. In this case we describe a patient who presented to the ED with cardiac tamponade and a new RUL mass that was hepatoid adenocarcinoma of the lung. Case Patient is a 69-year-old male with past medical history significant for long term tobacco use, hypertension, peripheral vascular disease, and OSA who presented to the hospital with shortness of breath and fatigue. He was found to be in cardiac tamponade and admitted to the ICU. In the ICU he had a pericardial drain placed. Pericardial fluid was negative for malignant cells. The patient then underwent navigational bronchoscopy and biopsy results showed adenocarcinoma with hepatoid morphology. Further immunostaining showed STK-11 mutation and a PDL-1 proportion score of 50%. PET CT showed uptake in left adrenal gland, right supraclavicular adenopathy, mediastinal adenopathy, as well as extensive bony metastasis. Brain MRI was negative for metastases. He was then referred to oncology for further evaluation and treatment of new hepatoid adenocarcinoma of the lung and is currently undergoing combination chemotherapy treatment with Ipilimumab, Nivolumab, Pemetrexed, and Carboplatin. Discussion This case highlights a rare presentation of hepatoid adenocarcinoma in a patient with classic risk factors for this malignancy. His age, gender, and smoking status are all associated with this malignancy and previous case series have shown an increased prevalence of the tumor presenting in the upper lobes. This case also highlights the STK 11 mutations and its continued poor prognosis among non-small cell lung cancers. This mutation has an estimated prevalence of 7.6% among adenocarcinomas of the lung and is associated with poorer response to immunotherapies and cytotoxic chemotherapy. This abstract is funded by: None
Kovats et al. (Fri,) studied this question.