Primary cystic tumors of papillary muscles of the heart are extremely rare. Here, one case of unusual cystic tumor in papillary muscle of the heart in a 37-year-old Myanmar migrant worker has been reported. He came to Malaysia 2 weeks before and one morning was found dead in sleep. Autopsy revealed cystic lesion in the papillary muscle of the mitral valve of heart, which was prolapsing into ventricular cavity. The cyst had white-jelly like sticky mucus material. The cyst was present in papillary muscle with slight invasion in septum area; it was lined by cuboidal-columnar epithelium and contained mucinous contents. There was no evidence of an inflammatory reaction in the cyst and in cardiac muscles. In addition to cystic neoplasm, the deceased also had histoplasmosis of the lungs. The case is presented with macroscopic and microscopic photographs of the cyst and histoplasmosis of the lungs. This case is reported because of its rarity, unique position, and unusual appearance.