INTRODUCTION: Primary malignant mesothelioma of liver is an extremely rare condition. Less than twenty cases have been reported so far in literature. This presents as liver mass and differentials include primary and secondary tumors of the liver. We describe the case of a 70-year-old male with asbestos exposure who was incidentally found to have primary malignant mesothelioma of liver in screening CT scan. CASE DESCRIPTION/METHODS: A 70-year-old non-smoker, nonalcoholic male with past medical history of pulmonary asbestosis (had a stable calcified pleural plaques, no evidence of metastatic disease in the chest) being followed with annual low dose CT scan for asbestosis exposure management was found to have an incidental liver mass in the CT scan. He did not have icterus, itching of the skin or change in his stool color or weight loss. Upon examination, he was found to be hemodynamically stable, there was no jaundice. There was no right upper quadrant tenderness on palpation. CT scan of abdomen with contrast was obtained that showed an 8 cm mass involving the right lobe of liver predominantly the segment 6 (Figure 1). This mass was highly concerning for liver malignancy. A bone scan was obtained for metastatic workup which did not reveal any metastatic disease. CT scan of the chest was done that did not show any evidence of hematogenous metastasis or mesothelioma in the thorax. His hepatitis panel, AFP level were negative. There was no elevation of liver enzymes. The patient underwent partial hepatectomy (segments V/VI), diaphragm resection and cholecystectomy. Biopsy of the liver mass showed a poorly differentiated malignancy, showing areas of epitheloid and spindle cell morphology. The tumor cells were positive for keratin AE1/AE3, keratin CAM 5.2, WT1, calretinin, CK20 and D2-40. Tumor cells were negative for arginase, CK 5/6, ERG, mucicarmine, MOC 31, BerEp4, desmin, S–100, and albumin in situ hybridization. The overall morphology as well as immunohistochemical staining pattern were most consistent with malignant mesothelioma. The patient was started on adjuvant chemotherapy with Pemetrexed and Cisplatin. DISCUSSION: Primary malignant mesothelioma of liver is an extremely rare condition. This presents a solitary lesion in the liver. Treatment includes surgical resection followed by adjuvant chemotherapy with Pemetrexed and Cisplatin. It should be considered as a differential in patients with solitary liver mass.