Primary Intrapulmonary Thymoma Appearing as a Solitary Pulmonary Nodule: The 'Master of Disguise' of Lung Tumors?

Primary intrapulmonary thymomas (PITs) are defined as thymomas arising in intrapulmonary locations, without an associated mediastinal component. They are rare lesions, the diagnosis of which can be very difficult. We present a case of PIT in an asymptomatic 74-year-old woman in whom pulmonary nodules were found on pulmonary angiography performed for an episode of pulmonary embolism. She underwent wedge resection and the pathology report revealed a PIT. We also summarize this patient's clinicopathological features and discuss the diagnosis, pathogenesis, and treatment of PIT.