Rapidly growing nodule on infant’s posterior thigh
The parents of a healthy 5-month-old boy bring him to the office for evaluation of an enlarging yellowish nodule on the back of his right thigh. It started as a pink macule several months ago and became yellow and lumpy over the last month. The infant was born at term and has grown and developed normally. His parents deny any trauma, but report occasional bleeding from the surface of the nodule. They deny any new medications or outdoor exposures. There is no history of new topical skin products.
The case
The parents of a healthy 5-month-old boy bring him to the office for evaluation of an enlarging yellowish nodule on the back of his right thigh. It started as a pink macule several months ago and became yellow and lumpy over the last month. The infant was born at term and has grown and developed normally. His parents deny any trauma, but report occasional bleeding from the surface of the nodule. They deny any new medications or outdoor exposures. There is no history of new topical skin products.
NEXT: What's the diagnosis?
Clinical presentation
Juvenile xanthogranuloma (JXG) is a reportedly rare (although in the authors’ experience, not so rare) non-Langerhans histiocytosis that most commonly affects infants and young children.1 It usually presents as a solitary or a few yellowish or red-brown firm papules or nodules most commonly on the head and neck, but which also can occur on the trunk and extremities (Figure).2
Etiology/Epidemiology
The etiology of JXG is unknown, but it is thought to involve a disordered macrophage response similar to other members of the histiocytoses group.3 It typically occurs in infants aged younger than 6 months, but has occurred in children aged up to 3 years. Cases have also been reported in adults.4
Clinical course
Juvenile xanthogranuloma is generally a benign disorder that resolves spontaneously without treatment. However, cases of extracutaneous involvement, multiple lesions, and systemic disease have been reported.1 The most frequently reported extracutaneous location is the eye, which can lead to blinding complications such as glaucoma or hyphema.5,6 However, this complication is actually rare.
Diagnosis/Pathology
Diagnosis is made clinically, although a “setting sun” yellow-orange structureless pattern with an erythematous border on dermascopic examination can be used.7 If biopsy is performed, histological examination reveals a dense histiocytic infiltrate within the papillary and reticular dermis composed of foamy, lipid-laden vacuolated mononuclear cells and Touton giant cells characterized by a ring of nuclei surrounded by foamy cytoplasm.8
Next: Newborn's rash is more than skin deep
Juvenile xanthogranuloma also has been associated with multiple syndromes including neurofibromatosis 1 and juvenile myelomonocytic leukemia.9
Patient outcome
The parents were provided with reassurance about the benign course of juvenile xanthogranuloma. Within the next 2 years, the patient’s JXG underwent spontaneous regression.
REFERENCES
1. Paxton CN, O'Malley DP, Bellizzi AM, et al. Genetic evaluation of juvenile xanthogranuloma: genomic abnormalities are uncommon in solitary lesions, advanced cases may show more complexity. Mod Pathol. 2017;30(9):1234-1240.
2. Yoon YH, Ju HJ, Lee KH, Park CJ. A cutaneous horn-like form of juvenile xanthogranuloma. Ann Dermatol. 2016;28(6):783-784.
3. Kirke S, Windebank K, Wood K, Taylor AE. Juvenile xanthogranuloma associated with contralateral lymphadenopathy. Pediatr Dermatol. 2005;22(5):424-426.
4. Frew JW, Murrell DF, Haber RM. Fifty shades of yellow: a review of the xanthodermatoses. Int J Dermatol. 2015;54(10):1109-1123.
5. Cypel TK, Zuker RM. Juvenile xanthogranuloma: case report and review of the literature. Can J Plast Surg. 2008;16(3):175-177.
6. Samara WA, Khoo CT, Say EA, et al. Juvenile xanthogranuloma involving the eye and ocular adnexa: tumor control, visual outcomes, and globe salvage in 30 patients. Ophthalmology. 2015;122(10):2130-2138.
7. Mun JH, Ohn J, Kim KH. Dermoscopy of giant juvenile xanthogranuloma. J Am Acad Dermatol. 2017;76(2S1):S76-S78.
8. Pretel M, Irarrazaval I, Lera M, Aguado L, Idoate MA. Dermoscopic "setting sun" pattern of juvenile xanthogranuloma. J Am Acad Dermatol. 2015;72(1 suppl):S73-S75.
9. Ferrari F, Masurel A, Olivier-Faivre L, Vabres P. Juvenile xanthogranuloma and nevus anemicus in the diagnosis of neurofibromatosis type 1. JAMA Dermatol. 2014;150(1):42-46.
Ms Fontecilla is a fourth-year medical student, Columbia University College of Physicians and Surgeons, New York, New York. Dr Cohen, section editor for Dermcase, is professor of Pediatrics and Dermatology at Johns Hopkins University School of Medicine, Baltimore, Maryland. The author and section editor have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have interest in any part of this article. Vignettes are based on real cases that have been modified to allow the author and editor to focus on key teaching points. Images also may be edited or substituted for teaching purposes.
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