May a morpho-molecular approach help in defining seudosarcomatous myofibroblastic proliferations? A study of a heart polypoid lesion

Abstract

Many cardiac neoplasms lack pathognomonic clinical features and lead to controversial interpretations. As genomic changes may correlate with these malignancies and possibly aid in diagnosis, we studied, using FISH, a polypoid lesion, incidentally found at autopsy on the septal wall of the left ventricle of a 75-year-old male who had died from a heart attack. Histology and immunohistochemistry disclosed atypical stromal cells with irregular voluminous nuclei positive for vimentin and smooth muscle actin, reminiscent of cells previously reported in a subset of nasal polyps showing aneuploidy. The scarce lymphoplasmacytic infiltrate hindering the diagnosis of inflammatory myofibroblastic tumors (IMT) and the presence of atypical cells, promped us to perform FISH: lack of ALK gene rearrangement and aneuploidy were observed in the irregular nuclei, supporting the diagnosis of a pseudosarcomatous myofibroblastic proliferation (PMP). These results stress that IMT and PMP may represent variants within a spectrum of myofibroblastic proliferations/tumours.