Lymphangioma is a malformation composed of a mass of dilated lymph vessels typically found in the cervical region in children. Mediastinal lymphangioma is a rare condition and accounts for 0.01% to 4.5% of all mediastinal tumors. Only 4 cases of mediastinal lymphangioma involving the heart and great vessels in adults have been described in the available literature. Extremely rarely, lymphangiomas occur as a generalized lymphangiomatosis. We present a case of a woman who coughed up small amounts of fresh blood during 6 months and showed signs of cardiac failure. Several years previously, the patient underwent surgical removal of cystic lymphangiomas from the left ovary, both fallopian tubes and small intestine. A chest radiograph showed an 8-cm round shadow located in the middle lobe. A computerized tomography (CT) scan of the chest with contrast verified the existence of a cyst in the anterior mediastinum. The radiologist suggested that the cyst could have originated in the pericardium. One small cyst also appeared in the projection of the left cardiophrenic sinus. A CT scan with contrast of the patient’s abdomen showed multiple cystic formations in the liver, spleen, kidneys, and left parapelvic region. A fine-needle biopsy of the mediastinal tumor verified the cystic lymphangioma, which was then completely removed surgically. A pathohistological examination confirmed the existence of cystic lymphangioma. The patient was discharged after a period of recovery.