A 2-year-old healthy Caucasian male is brought in by his mother for evaluation of a solitary mass-like lesion that developed on his scalp over the past couple of months. The nodule was asymptomatic. His mother denies other symptoms or medical problems. Physical examination was normal except for a 1cm yellow, dome-shaped, smooth nodule on scalp apex (Figure 140-1). Clinical diagnosis of juvenile xanthogranuloma was made and mother was given reassurance that lesion would regress spontaneously over the next months.

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  Juvenile Xanthogranuloma (JXG) is considered a benign, non-Langerhan cell, histiocyte proliferation disorder.

  
  
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  It usually presents as a solitary or few dome shaped red to yellow papules involving the upper body, although many variants are known to exist.

  
  
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  Juvenile Xanthogranuloma usually only involves the skin. These lesions generally resolve spontaneously within months to years.

  
  
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  Rarely JXG may be associated with systemic findings such as involvement of the central nervous system, liver, spleen, lungs, eyes, oropharynx, and muscle.¹ Only 5 patients (3.9%) of 129 patients were found to have systemic involvement in a retrospective review of a German pediatric tumor registry.²

  
  
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  There is a 0.3–0.5 percent incidence of ocular JXG. Children at maximum risk are 2 years of age or younger, have multiple skin lesions, and are newly diagnosed JXG.³ Two percent of JXG involving the eye are complicated by blindness usually from hyphema or glaucoma.⁴

  
  
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  Juvenile Xanthogranuloma may also be associated with other disorders including neurofibromatosis 1, juvenile chronic myelogenous leukemia (CML), urticaria pigmentosa, insulin-dependent diabetes mellitus, aquagenic pruritis, and possibly cytomegalovirus infection. Children with JXG associated with NF1 have a 20 time increased risk of developing CML.¹

  
  
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  The xanthomas of JXG are not associated with primary hyperlipidemia.⁴

Nevoxanthoendothelioma, xanthoma multiplex, juvenile xanthoma, congenital xanthoma tuberosum, xanthoma neviforme, and juvenile giant-cell granuloma.

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  Disease incidence is unknown. JXG may be under recognized and under reported. The relative incidence from a retrospective review of 26,400 patients was 0.52 percent.^2,5

  
  
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  It commonly affects children 2 years or younger with 75 percent of cases diagnosed by age 1, and 15 percent of cases presenting at birth.⁴

  
  
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  There may be a slight male predilection in children. Estimates run between 1.5 to 4: 1 male to female ratio.¹

  
  
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  It may rarely present in adults.

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  The pathogenesis is unknown.

  
  
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  There is still controversy about the origin of the cell involved and histiologic criteria since there is a mixed pattern among the non-Langerhans cell histiocyte proliferation disorders with many authorities considering them all a spectrum of the same disorder.^2,4

Clinical Features

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  There are two distinct variants in presentation. First there is a small nodular form with multiple pink, 2 to 5mm, dome-shaped papules that become red-brown and later turn yellow. They mainly affect the upper trunk (Figure 140-2).

  
  
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  The second variant is the large nodular form in which a solitary or a couple of 1 to 2 cm nodules develop (Figure 140-3).

  
  
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  Both variants may coexist at the same time.