KRAS mutation in papillary fibroelastoma: a true cardiac neoplasm?

Abstract

Primary cardiac tumours are rare and mostly benign lesions. Recent publications report that cardiac papillary fibroelastomas are the most common benign primary heart tumour, outnumbering myxomas. However, there is no consensus about their aetiology. We investigated the molecular profile of these tumours using next generation sequencing in a cohort of 16 cases. Eleven of 14 (79%) analysable tumours showed mutations of the KRAS oncogene. Our results provide unambiguous evidence that a significant proportion of these lesions are genuine neoplastic tumours caused by an oncogenic driver mutation.

Keywords: KRAS mutation; papillary fibroelastoma; primary cardiac tumours.

Figure 1

Macroscopic and microscopic characteristics of papillary fibroelastomas: (A) Microscopically avascular tumours with numerous papillary fronds attached to the endocardium by a short stalk. H&E staining, 25× magnification, macroscopically distinctive ‘sea anemone‐like’ appearance (insert bottom right). (B) The papillary fronds are lined by endothelium and show a central core of dense, hyalinised connective tissue surrounded by loose connective tissue. EvG staining, 200× magnification.

Figure 2

Transesophageal echocardiography of a papillary fibroelastoma (asterisks) of the left coronary leaflet of the aortic valve: (A) Atypical short axis view of 49°. (B) Long axis view showing the left ventricular outflow tract, the aortic valve, the fibroelastoma and the aortic bulb. (C) Three‐dimensional reconstruction of the aortic valve.