SMN1 and leiomyoma: 2015; Mikami 2018). SMA is known to be a better screening protein for muscle tumours compared to desmin (Folpe and Cooper 2007). Both tumours in this case expressed SMA while immunodetection of desmin was only observed in the myxoid leiomyoma. The intensity of positive staining for both SMA and desmin negatively correlates with the grade of mesenchymal tumours (Turner and Goldsmith 2009). In addition, higher grade tumours have higher mitotic activity, and vice versa (Singer et al. 1996).