RUNX‐1 and CD44 as markers of resident stem cell derivation in undifferentiated intimal sarcoma of pulmonary artery

Abstract

We report a case of pulmonary artery UIS expressing previously unreported markers, i.e. RUNX-1, nestin, WT1, and CD44, that are commonly seen in different stages of the vascular differentiation hierarchy. These findings, together with the negativity for mature endothelial and smooth muscle markers, raise the question of whether this neoplasm may derive from a vessel wall-resident stem cell, such as the haemangioblast or an embryonic-like stem cell.