title: Polypoid osteosarcoma of the left atrium: report of a new case with autopsy confirmation and review of the literature.
abstract: We describe a new case of heart osteosarcoma manifesting as a large polypoid mass of the left atrium. Clinically, the lesion presented with dyspnea, syncopal attacks, and fever. Ultrasound scans of the heart were suggestive of a cardiac myxoma, although some imaging features could retrospectively indicate a malignant neoplasm. In particular, the lesion was relatively immobile, did not show the characteristic myxoma motion during the heart cycle, and extended into the left pulmonary veins. Exploratory thoracotomy showed a nonresectable polypoid mass of the left atrium widely infiltrating the myocardium and the epicardium, histological features of a polymorphic sarcoma. The patient died 5 months after presentation with diffuse metastases. At autopsy, a 5-cm polypoid tumor was seen protruding into the left atrium. Neoplastic infiltration of the atrial myocardium, pericardium, and pulmonary veins was evident. Extensive metastatic deposits were observed in numerous sites, including the skin, lung, liver, and brain. Microscopically, a spindle cell sarcoma forming malignant osteoid was seen, admixed with areas indistinguishable from myxoid and pleomorphic malignant fibrous histiocytoma. This case provides further evidence that although rare, osteosarcoma of the heart usually presents as a polypoid mass of the left atrium and is histologically characterized by conspicuous polymorphism. It is associated with a poor prognosis and rapid appearance of distant metastases. Although at echocardiography it may mimic a myxoma, subtle features such as tumor extension into pulmonary veins and main origin from nonseptal atrial walls suggest the presence of a nonmyxomatous tumor and a preoperatory diagnosis of aggressive malignant disease.
authors.affiliation: Division of Anatomic Pathology, City Hospital, Conegliano TV, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Zanella
authors.forename: G
authors.initials: G
authors.lastname: Falconieri
authors.forename: R
authors.initials: R
authors.lastname: Bussani
authors.forename: G
authors.initials: G
authors.lastname: Sinagra
authors.forename: D
authors.initials: D
authors.lastname: Della Libera
mesh_terms: D000328:Adult; D001344:Autopsy; D004562:Electrocardiography; D006325:Heart Atria / Q000000981:diagnostic imaging; D006338:Heart Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D012516:Osteosarcoma / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography