PA32 A rare case of symmetrical giant facial plaque-type juvenile xanthogranuloma

Abstract Juvenile xanthogranuloma (JXG), a form of non-Langerhans cell histiocytosis, is a rare benign condition estimated to affect 1 per million children. In 80% it presents as a solitary papule or nodule. There are several described subtypes of JXG including mixed, giant, subcutaneous, eruptive, clustered and plaque-like. Symmetrical giant facial plaque-type JXG is a very rare subtype, first described by Gunson and Birchall in 2008 Gunson TH, Birchall NM. Symmetrical giant facial plaque-type juvenile xanthogranuloma. J Am Acad Dermatol 2008; 59 (2 Suppl. 1): S56–7. We present a 2-year-old girl with a slowly progressive, asymptomatic, symmetrical orange-coloured rash on both cheeks that started around age 1 year. She was otherwise well. Examination showed well demarcated, orange-coloured indurated plaques covering both cheeks in a mask-like distribution. There was no lymphadenopathy or hepatosplenomegaly. There were no signs of neurofibromatosis. Full blood count, renal and liver function tests and lipids were normal. Biopsy showed subepidermal sheets of histiocytic proliferation. Lesional cells were positive for CD68 and negative for SOX10, compatible with JXG. She is currently awaiting ophthalmology assessment and an ultrasound scan of her abdomen. Over the course of her follow-up, the plaques have slowly extended, spreading onto the temples and chin, the axillae and both upper arms. JXG belongs to the proliferative dendritic-cell-related disorders and is the commonest form of non-Langerhans histiocytosis (Itin K, Häusermann P, Itin P, Fosse N. Symmetrical facial giant plaque-type juvenile xanthogranuloma: case report and review of the literature. Case Rep Dermatol 2021; 13: 399–406). It is most often characterized by a solitary red–yellowish benign papule ( 0.5 cm) or nodule ( 2 cm) that usually involves the head and neck (42%) or trunk (20–40%), although involvement at any body site can occur, including extracutaneous sites (the eye being the most common). It may be congenital, but most cases develop in the first year of life. It more commonly affects male patients, in a ratio of up to 7 : 1. There is usually spontaneous resolution, which takes months to years, leaving an atrophic scar. The giant symmetric facial subtype of JXG is exceptionally rare, with only five reported cases worldwide. In these cases, there was no spontaneous resolution during a follow-up period of between 2 and 6 years. None of the reported cases had systemic or extracutaneous involvement. Treatment options are undefined – one child had a partial response to a single fractionated CO2 laser treatment. We present this case to highlight awareness of this unusual presentation.