Background Juvenile xanthogranuloma (JXG) belongs to the heterogeneous group of non-Langerhans cell histiocytosis and is caused by an accumulation and proliferation of macrophages. In the majority of cases JXG is a disorder of early childhood presenting during the first 2 years of life. The typical presentation is a solitary reddish or yellowish skin papule or nodule with spontaneous regression and no need for treatment. Case presentation Two infants with an atypical presentation of JXG, one with multiple blueberry muffin rash-like skin lesions and the other with severe multi-systemic involvement, are reported. Diagnosis was established by skin biopsy including histological work-up and immunostaining, where markers for macrophages (CD68 and CD163) exhibited significant reactivity. Conclusion JXG is the most common of the non-Langerhans cell histiocytosis. The typical presentation is a solitary skin lesion. The purpose of this report is to familiarize paediatricians with an unusual variant of this entity in order to facilitate early diagnosis and raise awareness for possible visceral complications and associated medical conditions.

Background and aims: Surgical resection is currently the cornerstone of liver tumor treatment in children. In adults radiofrequency ablation (RFA) is an established minimally invasive treatment option for small focal liver tumors. Multiprobe stereotactic RFA (SRFA) with intraoperative image fusion to confirm ablation margins allows treatment for large lesions. We describe our experience with SRFA in children with liver masses. Methods: SRFA was performed in 10 patients with a median age of 14 years (range 0.5-17.0 years) suffering from liver adenoma (n ¼ 3), hepatocellular carcinoma (n ¼ 1), hepatoblastoma (n ¼ 2), myofibroblastic tumor (n ¼ 1), hepatic metastases of extrahepatic tumors (n ¼ 2) and infiltrative hepatic cysts associated with alveolar echinococcosis (n ¼ 1). Overall, 15 lesions with a mean lesion size of 2.6 cm (range 0.7-9.5 cm) were treated in 11 sessions. Results: The technical success rate was 100%, as was the survival rate. No transient adverse effects higher than grade II (Clavien and Dindo) were encountered after interventions. The median hospital stay was 5 d (range 2-33 d). In two patients who subsequently underwent transplant hepatectomy complete ablation was histologically confirmed. Follow-up imaging studies (median 55 months, range 18-129 months) revealed no local or distant recurrence of disease in any patient. Conclusions: SRFA is an effective minimal-invasive treatment option in pediatric patients with liver tumors of different etiologies.

Background Hyaline fibromatosis syndrome is an autosomal recessive disease caused by mutations in ANTXR2 which leads to loss of function of the transmembrane protein anthrax toxin receptor 2. It is distinguished by characteristic skin lesions, gingival hyperplasia, joint and bone disease, and systemic involvement. Methods Based on the case of an 11‐year‐old female patient with typical features of hyaline fibromatosis syndrome and the underlying pathogenic compound heterozygote variants in ANTXR2 we discuss the genetic and clinical aspects of hyaline fibromatosis syndrome. Results The novel mutation in ANTXR2 (c.1223T>C, p.Leu408Pro variant) seems to allow for a protracted course of the disease. Conclusion Our findings add to the phenotypic, genetic, and biochemical spectrum of hyaline fibromatosis syndrome.