BACKGROUND: Xanthoma disseminatum (XD) is a rare form of non-Langerhans histiocytosis with extensive cutaneous involvement. There is a paucity of evidence-based recommendations for treatment decision-making. Previous case reports have established purine analogues, especially cladribine, as a hopeful first-line treatment option, but characterization of the clinical and pathological responses is lacking.
OBJECTIVE: To characterize the clinical and pathological responses to cladribine monotherapy based on serial examinations in XD patients.
METHODS: We retrospectively studied the clinical, pathological and laboratory data in a cohort of five XD patients who received intravenous cladribine monotherapy with serial examinations in our hospital. Compared with baseline characteristics, changes in clinical features and pathological patterns were identified and analysed. We also conducted a literature review of reported cases of cladribine treatment in XD patients.
RESULTS: Four male and one female patient were involved in the study. All patients demonstrated satisfactory clinical responses to cladribine monotherapy after 5 to 10 cycles. We observed a pathological shift in pattern from classic xanthogranuloma to transitional fibrohistiocytic infiltration during the treatment, and pathological responses heralded persistent clinical improvement. Other than afebrile neutropenia, no prominent adverse events were identified. Sustainable lesion clearance was achieved in all five patients during the follow-up period, ranging from 19 to 66 months.
CONCLUSIONS: Cladribine monotherapy is an effective and well-tolerated therapeutic option for XD patients. Pathological transformation is a signature of the clinical response and possibly unveils the underlying histiocyte biology of diseases in the xanthogranuloma family.

Juvenile Xanthogranuloma (JXG) is a non-hereditary, self-limiting disease which is usually presented in infancy or early childhood and in males over females.
We report a rare case of oral Juvenile Xanthogranuloma with recurrent progressive gingival hyperplasia and concomitant presentation of osteolysis in a 21-year-old adult male with no significant medical history. Patient presented with generalized gingival hyperplasia, osteolysis of the maxilla and mandible, and a round, firm, nodular mass with clear circumference on the left shoulder. Results of gingival tissue biopsy, karyotype, bone marrow biopsy and immunohistochemistry were suggestive of a diagnosis of Juvenile Xanthogranuloma with no association to hematologic malignancy. Unfortunately, patient declined treatment and elected to be transferred back to local hospital for future evaluation.
Juvenile Xanthogranuloma in adults can have atypical manifestations including generalized gingival hyperplasia and osteolysis of the maxilla and mandible. It should be differentiated between Langerhans cell histiocytosis, Papillon-Lefevre Syndrome, and Pyogenic Granulomas. Despite uncommon incidence, it should be included in differential diagnoses in cases of similar clinical presentations.

Juvenile xanthogranuloma is rare in children and there are limited data on its imaging features.
To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) features of juvenile xanthogranuloma in children.
A retrospective review was performed of clinical and radiographic data of histologically confirmed juvenile xanthogranuloma between January 2009 and June 2020.
Fourteen children (4 girls, 10 boys; age range: 1 day to 13 years, mean age: 73 months) were included in the study: 4/14 had CT only, 5/14 had MRI only and 5/14 had CT and MRI. Sites of extracutaneous juvenile xanthogranuloma involvement included subcutaneous soft tissue (8/14), liver (2/14), lungs (2/14), kidney (2/14), nose (2/14), pancreas (1/14), central nervous system (1/14) and greater omentum (1/14), mainly manifested as single or multiple nodules or masses in different organs. On CT, the lesions mainly manifested as an iso-hypo density mass with mild or marked enhancement. On MRI, the lesions mainly manifested as slightly hyperintense on T1 and slightly hypointense on T2, with decreased diffusivity and homogeneous enhancement. Juvenile xanthogranuloma was not included in the imaging differential diagnosis in any case.
Juvenile xanthogranuloma mainly manifests as single or multiple nodules or masses in different organs. Slight hyperintensity on T1 and slight hypointensity on T2 with decreased diffusivity and homogeneous enhancement are relatively characteristic imaging findings of juvenile xanthogranuloma. Combined with its typical skin lesions and imaging features, radiologists should include juvenile xanthogranuloma in the differential diagnosis when confronted with similar cases.

BACKGROUND: Molluscum contagiosum (MC), milia, keratosis pilaris (KP), verruca plana (VP), seborrheic keratosis (SK), and juvenile xanthogranuloma (JXG) are common papule dermatoses on the face of children that have a similar appearance. In vivo evaluation of facial papule dermatoses with reflectance confocal microscopy (RCM) is helpful in the diagnosis of these ambiguous lesions in children. The purpose of this study was to clarify the RCM characteristics of MC, milia, KP, VP, SK, and JXG and explore the clinical application value of RCM for these common facial papule dermatoses.
METHODS: We recruited 113 patients referred for unequivocal facial papule dermatosis, including 21 patients with MC, 17 patients with milia, 19 patients with KP, 36 patients with VP, 8 patients with SK, and 12 patients with JXG. We evaluated the characteristics and distinguishing features of the six kinds of facial papule dermatoses using RCM.
RESULTS: The main RCM features of the six dermatoses included a well-demarcated border of the lesion area. MC, milia and KP all manifested cyst-like structures, and their distinguishing features were the location of the cystic structures and the refractive index of the contents. Although VP, SK, and JXG did not have obvious cystoid structures, VP was typically characterized by uniformly distributed petal-like structures with a medium-to-high refractive index in the epidermis. With regard to SK, the characteristic features were an obviously thickened epidermis and cobblestone-like structures. JXG was mainly characterized by multiple large round and ovoid cells with a foamy cytoplasm, and discoid-shaped multinucleated large cells were diffusely distributed in the dermis.
CONCLUSIONS: RCM allows the real-time visualization of major key diagnostic and distinguishing features of common facial papule dermatoses in children, including MC, milia, KP, VP, SK, and JXG.

Juvenile xanthogranuloma (JXG) is a kind of non-Langerhans cell histiocytosis, usually with skin lesions as the main manifestation. It rarely occurs in other tissues or organs and even more rarely is it found in the skull. Here, we report a case of xanthogranuloma derived from the temporal bone that was not present in any other parts of the body.
A 15-year-old boy had an unaccountable right migraine for 7 months. A mass with tenderness was located behind his right ear. The mass gradually increased in size, and his headache continued. Eventually, he came to our hospital for treatment. A computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed a cystic solid mass in the right temporo-occipital region with skull destruction. The clinical diagnosis was haemangiopericytoma and skull-derived tumour. Haematological and biochemical results were as follows: alanine aminotransferase (ALT) 7 U/L; aspartate aminotransferase (AST) 12 U/L; basophil percentage (BASO%) 1.2%; normal coagulation. The patient was successfully treated with total surgical resection of the tumour. Postoperative histopathology examination showed xanthogranuloma, and his prognosis after surgery was good.
Because JXG rarely occurs in the skull and lacks typical imaging findings, an accurate diagnosis is difficult. The diagnosis of this disease mainly depends on pathological examination and immunohistochemistry. If feasible, many intracranial lesions can be cured through complete resection.

OBJECTIVE: Solitary eyelid juvenile xanthogranuloma (JXG) is extremely rare, and there is limited literature on its clinical features and treatment outcomes. Here, we present a case series and comprehensive review of the literature on patients with isolated eyelid JXG.
METHODS: We systematically extracted data from our institution\'s records of isolated eyelid JXG cases and conducted a search for additional cases from the literature utilising the PubMed, Wanfang, and Chinese National Knowledge Infrastructure (CNKI) databases. Patients with JXG were analysed with respect to age, sex, clinical presentation, therapy, and outcome. Group comparisons were performed.
RESULTS: Thirty-two patients (including 13 at our institution and 19 from prior publications) were identified. The median age at first presentation was higher in current patients than in the patients from the published cases (median 9 years, range 1.2 to 47.0 years; median 2 years, range 0.5 months to 46.0 years, respectively, P = 0.014). Of the patients who had known characteristics, no significant differences were observed between the two groups in terms of sex, affected eye, eyelid site, type of cutaneous involvement, or duration of symptoms (each P > 0.05). Seventeen (54.8%) patients were male. The most common lesion location was the upper eyelid (n = 10, 62.5%). Twenty-four (75.0%) cutaneous lesions had full-thickness skin involvement; 8 (25.0%) subcutaneous masses had a chalazion-like appearance. Histologically, the JXG masses were characterised by Touton giant cells with inflammatory cells. Additionally, there was no significant difference in treatment modalities between the two groups (P = 0.072), and 24 (75.0%) patients underwent surgical excision. The overall recurrence-free survival was 3.6 to 52.8 (median 27.0) months in the current patients. For published cases with available follow-up information, there was no recurrence in 10 cases and improvement in 1 case, with a median follow-up of 9.5 months.
CONCLUSIONS: Solitary eyelid JXG is a rare clinical entity and should be included in the differential diagnosis of eyelid mass lesions in patients of all age groups. Surgical excision is often selected for efficient treatment and to obtain an excisional biopsy.

Objective: To investigate the clinical characteristics, treatment, and prognosis of children with systemic juvenile xanthogranuloma (JXG). Methods: Clinical data of children with JXG who were hospitalized in Beijing Children\'s Hospital, Capital Medical University, from January 2012 to December 2019 were retrospectively analyzed, including clinical manifestations, laboratory determinations, treatment, and prognosis of the children. Patients were treated with vindesine + prednisone as the first-line treatment and cytarabine + vindesine + dexamethasone ± cladribine as the second-line treatment. Results: Ten patients, including 8 males and 2 females, with a median of onset age of 1.95 (0.80-7.30) years, exhibited multi-system dysfunction. The median age of diagnosis was 2.45 (1.30-12.10) years. The most common location of extracutaneous lesions was the central nervous system (6 cases), followed by the lung (5 cases) and bone (4 cases). Nine patients underwent first-line chemotherapy, and 6 patients underwent second-line chemotherapy, including 5 patients with poorly controlled disease after first-line treatment. The median observation time was 29 (3-115) months. Nine patients survived, whereas one patient died of respiratory failure caused by pulmonary infection. At the end of follow-up, 7 patients were in active disease (AD)/regression state (AD-better), and 2 patients were in an AD/stable state (AD-stable). Three patients had permanent sequelae, mainly central diabetes insipidus. The rates of response to the first-line treatment and the second-line treatment were 40.0 and 66.7% respectively. Conclusion: The chemotherapy protocol for Langerhans cell histiocytosis (LCH) may be effective for patients with systemic JXG. Central nervous system involvement may not impact overall survival, but serious permanent sequelae may occur.

Background: Several dermoscopic features of juvenile xanthogranuloma (JXG) have been previously described in single cases or small case series and need to be further verified in a large sample. Objective: We aimed to investigate the dermoscopic patterns of JXG in a large case series and the correlations of these with clinical features of different histopathological subtypes of JXG. Methods: Patients who underwent dermoscopic evaluation and had a histopathological diagnosis of JXG were recruited. Histological findings, including stage and Ki67 proliferative index and the dermoscopic features of each lesion were recorded. Results: Forty-one patients with JXG were included. The male to female ratio was 1.28: 1 and the median age of onset was 11 months (range: 0-95 months). Fourteen lesions were histologically categorized in the early stage, 17 in the developed stage, and 10 in the late stage. The \"setting sun\" pattern was observed in 35 lesions (85.4%) and \"clouds\" of paler yellow areas in 26 lesions (63.4%). The frequency of the \"setting sun\" pattern was higher in the early and developed stages (30/31) than in the late stage (5/10) (P = 0.002), while that of \"clouds\" of paler yellow areas was not significantly different between each stage. Branched linear vessels were detected in the early (11/14) and developed stage (6/17), but not in the late stage. The mean Ki67 index of the lesions with linear vessels was 11.8% (range: 2-40%), which was higher than that of lesions without linear vessels (mean index: 5%, range: 1-30%) (P = 0.005). The pigment network and whitish areas were only detected in 6 and 5 lesions in the late stage, respectively. The whitish areas presented either as streak or stellate shape. The pigment network exhibited either in a centric or a peripheral pattern. Conclusions: The \"setting sun\" pattern is the characteristic dermoscopic features of JXG in the early and developed stages, while whitish areas and pigment network are the characteristic patterns in the late stage. Linear vessels present as branched patterns and mostly occur in the early stage with a high proliferative index, indicating rapid growth. The whitish areas and pigment network may present in various patterns. Dermoscopy is a useful adjunctive tool in the diagnosis and staging of JXG.

Juvenile xanthogranuloma (JXG) is the most common non-Langerhans cell histiocytic disorder in children. This report describes the case of a 28-day-old boy that presented with multiple subcutaneous nodular lesions on the trunk and extremities, and multiple red nodular lesions on the scrotum. Magnetic resonance imaging (MRI) of the brain showed a well-demarcated extra-axial dura-based mass that appeared isointense or slightly hyperintense on T1-weighted images, hypointense on T2-weighted images and had intense enhancement on gadolinium-enhanced T1-weighted images. Computed tomography (CT) or MRI scans of the chest and abdomen revealed multiple scattered nodular or patchy lesions of varying sizes in the lungs, liver and left kidney. Histological analysis of a subcutaneous mass suggested JXG. The patient was diagnosed with neonatal systemic JXG with involvement of the central nervous system, lungs, liver, kidneys, subcutaneous soft tissue and skin. CT and MRI after 3 months of treatment with methylprednisolone sodium succinate demonstrated that the lesions were obviously diminished. This report discusses the imaging findings in this current case of multi-organ JXG and reviews the imaging literature on this condition to improve awareness of the lesions in order to help radiologists establish an accurate differential diagnosis when confronted with similar cases.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disease with many manifestations, and it involves any organ. In this study, we report a TSC patient with new type skin lesions.
A 7-month-old TSC boy with multiple cutaneous nodules was admitted in our hospital. We collected the clinical data of the patient. We performed biopsy of cutaneous nodules and whole-exome sequencing in both paraffin block tissue and blood samples.
The patient presented with a 2 month history of gradual growth multiple cutaneous nodules. He had cardiac rhabdomyoma, subependymal giant cell astrocytoma (SEGA) and hypomelanotic macules. The pathological finding of cutaneous nodules was consistent with juvenile xanthogranuloma (JXG). After 3 months of sirolimus treatment, the multiple nodules disappeared. The whole-exome sequencing identified TSC1 (c.2356C > T, p.R786*) mutation in both paraffin block tissue and blood samples. We overturned the original pathological diagnosis and finally identified JXG as a new type of skin lesions in TSC.
This is the first report on the occurrence of JXG skin lesions in TSC patient. Genetic testing is necessary in JXG. These findings expand the phenotype of skin in patients with TSC and contribute to the elucidation of JXG pathogenesis and treatment.