Pulmonary sclerosing hemangioma (PSH) is a benign tumor that usually presents as a solitary, well-defined mass in the lung. The PSH predominantly affects females with a higher incidence in the Far East. Histologically, the tumor cells in PSH consist of two cell types (cuboidal epithelial and polygonal stromal cells). Immunohistochemical and ultrastructural studies have identified that both cells are derived from undifferentiated respiratory epithelium that is the histologic origin of lung adenocarcinoma as well. Previous studies have shown that PSH and adenocarcinoma in the lung share some immunohistochemical and genetic features. However, as for somatic mutations, whereas many driver genes for lung adenocarcinomas have been identified, there have not been any candidate driver mutations identified in PSHs, except for low frequency mutations in β-catenin and TP53. Frequent somatic mutations identified in lung adenocarcinomas such as KRAS and EGFR have not been detected in PSH, suggesting that genomic alterations of these two lung tumors might be different from each other. Also, there is no evidence of PSH progression to lung cancers. These earlier data indicate that despite the common cellular origin of PSH and lung adenocarcinoma, genetic mechanisms for their development may be different. Based on the established concept that PSH is a true tumor, we hypothesize that it may harbor somatic mutations. In this study, we conducted whole exome sequencing of 44 PSHs and identified recurrent somatic mutations of AKT1 (43.2%) and β-catenin (4.5%). We used a second subset of 24 PSHs to confirm the high frequency of AKT1 mutations (overall 31/68, 45.6%; p.E17K, 33.8%) and recurrent β-catenin mutations (overall 3/68, 4.4%). Of the PSHs without AKT1 mutations, two exhibited AKT1 copy gain. AKT1 mutations existed in both epithelial and stromal cells. In two separate PSHs from one patient, we observed two different AKT1 mutations, indicating they were not disseminated but independent arising tumors. Since the AKT1 mutations were not found to co-occur with β-catenin mutations (or any other known driver alterations) in any of the PSHs studied, we speculate that this may be a single most common driver alteration to develop PSHs. Our study revealed genomic differences between PSHs and lung adenocarcinomas including a high rate of AKT1 mutation in PSHs. These genomic features of PSH discovered in the present study provide clues to understanding the biology of PSH and for differential genomic diagnosis of lung tumors.