Cutaneous Pebbling in Hunter Syndrome: A Distinctive Clinical Marker for Early Diagnosis

Abstract

Hunter syndrome, also known as mucopolysaccharidosis type II, is a lysosomal storage disorder characterized by iduronate-2-sulfatase (IDS) deficiency, leading to impaired degradation of mucopolysaccharides. We here report the case of a 6-year-old boy who developed several asymptomatic skin-colored raised lesions on the upper back, upper chest, and outer parts of both upper arms and legs over a duration of 3 years. In addition, he lacked both upper and lower molars, had bilateral hearing loss, restricted joint movements, and developmental delay. Numerous firm, flesh-colored papules ranging from 5 to 10 mm were seen upon cutaneous assessment. These papules merged to form a plaque over the upper back, upper chest, and outside areas of both the upper arms and thighs, giving the impression of cobblestones (pebbling of the skin). A skin biopsy showed orthokeratosis and demonstrated extensive mucin deposition around hair follicles, in the mid- and deep dermis, with widely separated collagen bundles, which are highlighted by Alcian Blue staining at pH 2.5. The child was found to have an IDS deficiency after an enzyme assay. Hunter syndrome was, therefore, identified. This case report of Hunter syndrome highlights a unique skin lesion that can aid in early diagnosis.