Cutaneous Features of Neurofibromatosis

Sang-Eun Kim , BSc, MSc, Faulty of Medicine, University of British Columbia, BC.
Joseph M Lam, MD FRCPC, Assistant Clinical Professor, Department of Paediatrics, Associate Member, Department of Dermatology,
University of British Columbia, BC.

Abstract
Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder that is characterized by café-au-lait spots, axillary or inguinal freckles, cutaneous neurofibromas, and skeletal dysplasias. Currently, there are no curative therapies for NF1 but medical therapies, including systemic sirolimus, have opened the door for significant medical advances in the treatment of NF1. Management of NF1 has been focused on routine examinations looking out for potential complications of NF1. However, many patients with NF1 are missed and may not be diagnosed early. The following review article will provide an overview of select common and uncommon cutaneous features of NF1 to help the practitioner recognize, diagnose and treat patients with NF1.
Key Words: Neurofibromatosis type 1, café-au-lait spots, axillary freckles, inguinal freckles, cutaneous neurofibromas.

INTRODUCTION
Neurofibromatosis type 1 (NF1) is an autosomal dominant, multisystem genetic disorder that affects the human nervous system. It is one of the most common single gene disorder that affects approximately one in 3,500 births.¹ Clinical diagnosis of NF1 requires the presence of at least 2 out of the following 7 criteria:

1. Six or more café-au-lait spots or hyperpigmented macules > 5 mm (prepubertal) or > 15 mm (postpubertal)
2. Axillary or inguinal freckles
3. Two or more typical neurofibromas or one plexiform neurofibroma
4. Optic nerve glioma
5. Two or more iris hamartomas, often identified only through slit-lamp examination by an ophthalmologist
6. Sphenoid dysplasia or typical long-bone abnormalities such as pseudarthrosis
7. First-degree relative with NF1

NF1 affects each person differently, even those from the same family, and it is difficult to predict the severity or progression of NF1. For the caregiver, the presentation of cutaneous features of NF1 can be a source of anxiety. For the physician, it can be a source of frustration as diagnosis can often be challenging and prognosis can be difficult to predict. The purpose of this review article is to provide a brief overview to assist practitioners with early identification, care, and management of common as well as uncommon cutaneous features of NF1.