Journal of Clinical and Investigative Dermatology
Case Report
Clinically Suspected Mosaic Legius Syndrome in a Yemeni Adolescent: A Rare Case Report
Alshami MA1*, Alshami AM2, Alshami HM1 and Lutf RM1
1Department of Dermatology, Faculty of Medicine and Medical Sciences,
Sana’a University, Yemen
2Department of Conservative Dentistry, Faculty of Dentistry, Sana’a University, Yemen
2Department of Conservative Dentistry, Faculty of Dentistry, Sana’a University, Yemen
*Address for Correspondence: Mohammad Ali Alshami, Department of Dermatology, Faculty of
Medicine and Medical Sciences, Sana’a University, Sana’a 1064, Yemen. E-mail Id: mohammadalshami62@gmail.com
Submission: 13 April, 2026
Accepted: 23 June, 2026
Published: 26 June, 2026
Copyright: © 2026 Alshami MA, et al. This is an open access
article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.
Keywords: Legius Syndrome; Mosaicism; Café-Au-Lait Macules;
Neurofibromatosis Type 1; Partial Unilateral Lentiginosis
Abstract
Legius syndrome, also known as neurofibromatosis type 1 (NF1)-
like syndrome, is an autosomal dominant condition characterized by
café-au-lait macules (CALMs) and freckling in the axilla or other sites,
without neurofibromas. Herein, we present a 14-year-old girl with a
two-year history of four CALMs on the forehead, left temple, left arm,
and right side of the back. Cutaneous examination revealed lentigines
on the axilla, chest, and right side of the back. Mosaic NF1 was
considered due to unilateral CALMs and axillary freckling; however,
neurofibromas were absent. Based solely on typical clinical findings,
mosaic Legius syndrome was diagnosed.