Received: 22 June 2020
Accepted: 31 July 2020
First Online: 12 August 2020
Ethics approval and consent to participate
: This study was approved by the institutional ethical review committee (approval number 2020044). Written informed consent was obtained from PM/DM patients. The requirement for informed consent for control was waived.
: Not applicable. All images and data were anonymous.
: The authors declare that they have no competing interests.