PDGFRA and pemphigus foliaceus: Few GISTs exhibited a plexiform and myxoid appearance similar to PF.[10] However, GISTs typically expressed CD117, DOG-1, and CD34 and were negative for SMA, S-100, desmin, and AE1/AE3.[2] In addition, 80% and 5% to 8% of GIST were primarily driven by the mutations in KIT and PDGFRA, respectively.[23] These aspects were not seen in PF.