In a pediatric patient, atypical dermal melanocytosis led to the diagnosis of mucopolysaccharidosis type II, also known as “Hunter’s disease.”
(red) Most often, atypical dermal melanocytosis is an isolated, harmless finding, but it may also mask metabolic disease or a rare syndrome.
A 16-month-old boy was referred to the dermatology department of the Children’s Hospital Zurich for evaluation of extensive persistent dermal melanocytosis. Past medical history was unremarkable except for recurrent respiratory infections and occasional wheezing. Development milestones were only slightly delayed. On inspection, areas of blue-gray hyperpigmentation were noted on the shoulders, back, buttocks, and extremities. The face and occiput were somewhat flattened, the abdomen slightly distended with a palpable liver about three centimeters below the rib cage.
For the detection of a possible lysosomal storage disease, glycosaminoglycans and oligosaccharides were measured in urine and blood. Glycosaminoglycan levels (heparan and dermatan sulfate) were elevated and iduronate-2-sulfatase enzyme activity was absent in leukocytes, leading to the diagnosis of mucopolysaccharidosis type II.
Source: Alvarez E, et al: A diagnosis out of the blue – Atypical dermal melanocytosis associated with mucopolysaccharidosis type II (Hunter’s disease), Poster 32, Abstract volume, SGDV Annual Meeting, 9-11.2022.
DERMATOLOGY PRACTICE 2023; 33(1): 37
