We aim to present a rare case of low-grade myofibroblastic sarcoma arising in the inguinal region accompanied by cardiac metastasis. A 36-year-old male patient suffering from recurrent inguinal swelling was operated on and the initial histopathological evaluation mistakenly diagnosed the condition as benign. During follow-up, a recurrence of mass was detected in the same region and a pathological examination revealed a low-grade myofibroblastic sarcoma. Cardiac metastasis was diagnosed shortly before rapid disease progression and death. The learning points relevant to this case are as follows: (1) Echocardiographic screening in patients with noncardiac myofibroblastic sarcomas may be helpful in the detection of silent metastasis. (2) Low-grade myofibroblastic sarcomas in the inguinal region may be misdiagnosed as benign after enucleation. Thus, rigorous histopathological examination of myofibroblastic sarcomas is crucial. (3) According to our knowledge, this is the first report of a low-grade myofibroblastic sarcoma to have a potential for cardiac metastasis with potentially fatal course.