Fig. 3

Pathological findings and follow-up. a Pathological examination findings reveal a white, substantial, mass lesion. Histology shows keloid-like proliferation of mature collagen fibers. Although the lesion is obsolete, there is a possibility of a myxoma in the background. Immunostaining is not suggestive of malignancy. b Contrast-enhanced computed tomography at recurrence 1 year later shows a tumor (yellow arrow) in the pulmonary valve (prosthetic valve) and pulmonary artery