Subaortic Membrane Papillary Fibroelastoma

Abstract

A 61-year-old male presented for an annual exam and received a transthoracic echocardiogram (TTE) which revealed a mobile mass arising from a subaortic membrane. Further investigations with a transesophageal echocardiogram (TEE) and cardiac computerized tomography angiography (CTA) confirmed the presence of a mobile 9 mm × 3 mm mass on a subaortic membrane. Cardiothoracic surgery was performed with an open operation removing the mass and subaortic membrane. Upon visual inspection, the mass was likened to a sea anemone and immunohistochemical staining performed pathologically confirmed the diagnosis of cardiac papillary fibroelastoma. This case represents the first reported example of a cardiac papillary fibroelastoma (PFE) arising from a subaortic membrane. Although PFEs are benign cardiac tumors, proper identification and consideration for excision of these lesions may be indicated to prevent thromboembolic complications.

Figure 1

(a) TTE imaging of a subaortic membrane and mass (arrow) on the anterior wall of the LVOT. (b) TEE imaging showing the mass (arrow) in close proximity to the aortic valve. (c) CTA showing a subaortic membrane (arrowhead) with an area of extension, likely representing a mass (arrow) in (d).

Figure 2

Gross specimens of the resected subaortic membrane (a) and mass (b) which has the classic frond-like appearance after being submerged in water. Histopathology with H&E stain revealing multiple papillae (c) which are avascular and rich in collagen (d) and CD34 staining highlighting the dark single layer of epithelial cells lining the mass.