Association of Central Precocious Puberty with a Rare Presentation of Schimmelpenning–Feuerstein–Mims Syndrome in a Peruvian Girl

Schimmelpenning–Feuerstein–Mims syndrome (SFM), an epidermal nevus syndrome characterized by skin lesions, has an estimated incidence of 1 per 10 000 live births. Nevus sebaceous, the most common cutaneous lesion, and verrucous nevus, the less frequent lesion, are coupled with a wide range of extracutaneous manifestations. As part of these manifestations, rarely, central precocious puberty can arise. We report the case of a 1-year-5-month-old girl who presented to the Endocrinology and Metabolism Department with breast enlargement that began at one year of age, growth of pubic and axillary hair three months later, and vaginal bleeding that occurred five months later. During clinical examination, melanocytic nevi, with a diameter ranging from 3 to 5 mm, were noted on the face. Verrucous nevi of variable size with a tendency for coalescence following the lines of Blaschko and melanocytic nevi with a diameter ranging from 3 to 6 mm were observed on the right hemibody and on the left hemibody, respectively. Right asymmetry of the lower extremities was observed. Laboratory findings showed a significant increase in the levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) after the gonadotropin-releasing hormone (GnRH) stimulation test; additionally, imaging demonstrated advanced bone age and pubertal changes in the internal genitals. Analyses of the H-RAS, K-RAS, and N-RAS genes in the blood and in the skin were performed, and a missense mutation in exon 2 of the gene, H-RAS c37G > C (p.G13R), was detected in the latter. Treatment with triptorelin, a GnRH analog, was initiated, and it gave good clinical response. Epidermal nevus syndrome has a wide and variable systemic involvement. Thus, it is important to consider the development of precocious puberty for a prompt diagnosis and to strategize a multidisciplinary approach from the beginning.