The effect of haematopoietic stem cell transplant on papules with 'pebbly' appearance in Hunter's syndrome.

BACKGROUND: Hunter's syndrome is associated with several cutaneous findings. For instance, papules with 'pebbly' appearance are a specific marker for the disease. However, it remains uncertain whether they disappear after haematopoietic stem cell transplant (HSCT).

OBJECTIVES: To investigate the papules with 'pebbly' appearance before and after HSCT in infants with Hunter's syndrome, and to clarify the effect of HSCT on papules.

PATIENTS: We observed five Japanese boys with Hunter's syndrome who had received HSCT at 4-11 years of age.

RESULTS: The post-HSCT physical examinations revealed that papules disappeared completely within 35 days after the transplant with progressive reduction of cutaneous tightness in all the patients. Histochemical findings showed that papules contained a large amount of hyaluronic acid in the extracellular materials of the dermis and sulphated acid mucopolysaccharides in dermal fibroblasts before HSCT.

CONCLUSIONS: These results suggest that papules with a 'pebbly' appearance fade away through the digestion of a large amount of hyaluronic acid in cutaneous tissues by normal tissue histiocytes or enzymes of donor origin at an early stage after HSCT.