[Pathologic analysis of primary cardiac inflammatory myofibroblastic tumor]

To study the clinical and pathologic features of primary cardiac inflammatory myofibroblastic tumor.

A total of 4 patients with primary cardiac inflammatory myofibroblastic tumor were encountered during the period from 1993 to 2013 in National Center for Cardiovascular Disease. The clinical features, imaging findings and outcomes of the 4 patients were evaluated. ALK protein expression and ALK gene status were studied using the archival tumor tissues.

There were 1 female and 3 male patients. The age of patients ranged from 5 months to 30 years (mean = 16 years). The tumor was located in right ventricle (n = 2), right atrium (n = 1) or pericardium (n = 1). Histologic patterns included 2 cases of fibrous histiocytoma type, 1 case of granulomatous type and 1 case of sclerosing type. Immunohistochemical study showed that 2 cases expressed ALK protein. Fluorescence in-situ hybridization however did not reveal any ALK gene rearrangement.

Inflammatory myofibroblastic tumor of the heart is rarely encountered and easily misdiagnosed. It carries distinctive clinical and pathologic features. ALK protein expression is helpful in arriving at the correct diagnosis.