Introduction: Mediastinal hemangiomas are uncommon benign vascular tumors. They are histologically classified into capillary, cavernous, and venous types, according to the size of their vascular spaces. Phleboliths, multiple enhanced vessels, and peripheral puddling of contrast enhancement are the typical diagnostic features on computed tomography (CT). The cardiophrenic angle (CPA) area is a particular area of mediastinum and diseases in this region are rare but various. This paper describes a case of cavernous hemangioma located in the right CPA, lacking the typical CT imaging findings, that was definitively diagnosed after surgery. Case Presentation: On March 20, 2017, a 38-year-old woman referred to Da-Ping hospital, which is a level III military hospital affiliated to the Army Medical University, Chongqing, China. She had a three-week history of intermittent cough, dull aching chest pain, and occasional palpitation. Her general physical examination and other routine lab tests and tumor markers were reported within the normal ranges. One day later, the chest plain CT showed a well-defined and non-invasive mass with soft-tissue density interspersed with a fatty ingredient in the right CPA with contrast agent. The tumor demonstrated non-enhancement neither in the arterial phase nor in the venous phase, and no apparent feeding vessels to the tumor were identified. It was initially suspected to be a benign ectopic thymoma. On March 27, 2017, the tumor was completely resected by video-assisted thoracoscopic surgery (VATS). Post-operative histological findings confirmed the diagnosis of cavernous hemangioma. The patient was in good condition at a five-month follow-up. Conclusions: Mediastinal cavernous hemangioma should be considered as an important differential diagnosis of mediastinal masses even though it is rare. Chest CT is useful in providing valuable information on the origin and invasiveness of the tumor, evaluating the relationship between tumors and intrathoracic vessels, and mapping the blood supply of tumors to select more suitable operative intervention.