Cardiac fibroma: A clinicopathologic study of a series of 12 cases

BACKGROUND: Cardiac fibroma (CF) is a rare tumor that has not been widely reported. This study investigated the clinical findings, histologic features, and differential diagnosis of CF. METHODS: A total of 12 CF cases were studied and reviewed using hematoxylin and eosin (H&E), special staining and immunohistochemical staining. The ALK gene was tested in 4 cases of cardiac fibroma with significant inflammatory cells. Clinicopathological data were retrospectively analyzed and followed up. RESULTS: The cases occurred in six males and six females ranging in age from 0.5 to 55 years (median, 5 years). The tumors were grossly single and solid (1-17 cm; mean 5.6 cm). The clinical signs and symptoms depended largely on the location of the tumor. Microscopically, the CFs observed were composed of monomorphic spindle cells and abundant collagen. The spindle cells demonstrated little or no atypia. The histology of CFs in infants and young children showed some differences from those in adults. Infants and young children with fibromas exhibited cellular types with more inflammatory infiltration. All tumors expressed vimentin markers. Eleven of 12 cases (91.7%) were positive for SMA by immunohistochemistry. ALK immunostaining and ALK-FISH tests showed negative results. Follow-up information was available for all patients. The mean postoperative follow-up was at 3 years (range 2 months-8.8 years). All patients were alive with no evidence of disease. CONCLUSIONS: Our study shows that CFs exhibit a wide morphological spectrum of soft tissue tumors with fibroblastic or myofibroblastic differentiation and/or components. Infants and younger pediatric patients with fibromas have tumors that are more hypercellular and more likely to be misdiagnosed with aggressive or malignant lesions than adults. Finally, the data indicate that CF exhibits benign behavior and that local resection is safe and effective.