BACKGROUND: The diagnosis of Neurofibromatosis type 1 (NF1) is usually delayed in children without a family history. We aimed to define the prevalence and characteristics of prevalent skin manifestations in NF1 compared to the general population, which continue to be excluded from the diagnostic criteria for NF1.
METHODS: Case-control study, matched by age groups, in which 108 patients with a diagnosis of NF1 and 137 healthy controls were included.
RESULTS: The prevalence of nevus anemicus (NA) (P<.001) and juvenile xanthogranulomas (JXG) (P<.001) was significantly higher in the population affected by NF1 than in the control population. A specificity of 99.27% (confidence interval): 95.4-99.96%] and a positive predictive value (PPV) of 98.80% [92.54-99.94%] were estimated for NA and a specificity of 99.27% [95.4-99.96%] and a PPV of 92.86% [64.17-99.63%] for JXG in the diagnosis of NF1 in children who present 6 or more Café-au-lait macules. Statistically significant differences were also evidenced in the distribution by phototypes (P=.025) and in relation to generalized itching with no other cause (P<.001).
CONCLUSIONS: NA and JXG are relevant clinical findings for the diagnosis of NF1, especially during the first years of life. We consider that its inclusion among the diagnostic criteria of the disease should be evaluated.

BACKGROUND: The diagnosis of Neurofibromatosis type 1 (NF1) is usually delayed in children without a family history. We aimed to define the prevalence and characteristics of prevalent skin manifestations in NF1 compared to the general population, which continue to be excluded from the diagnostic criteria for NF1.
METHODS: Case-control study, matched by age groups, in which 108 patients with a diagnosis of NF1 and 137 healthy controls were included.
RESULTS: The prevalence of nevus anemicus (NA) (p<0.001) and juvenile xanthogranulomas (JXG) (p<0.001) was significantly higher in the population affected by NF1 than in the control population. A specificity of 99.27% [confidence interval (CI): 95.4-99.96%] and a positive predictive value (PPV) of 98.80% [92.54-99.94%] were estimated for NA and a specificity of 99.27% [95.4-99.96%] and a PPV of 92.86% [64.17-99.63%] for JXG in the diagnosis of NF1 in children who present 6 or more Café-au-lait macules. Statistically significant differences were also evidenced in the distribution by phototypes (p 0.025) and in relation to generalized itching with no other cause (p<0.001).
CONCLUSIONS: NA and JXG are relevant clinical findings for the diagnosis of NF1, especially during the first years of life. We consider that its inclusion among the diagnostic criteria of the disease should be evaluated.

OBJECTIVE: Ophthalmic histiocytic lesions comprise a heterogeneous rare group of disorders that are characterized by an abnormal proliferation of histiocytes and may affect all age groups of both sexes. The aim of this study was to highlight the basic demographic, clinical, and histopathological characteristics of this rare group of diseases in ophthalmic practice, which has not been previously studied in this area. Only individual cases have been previously reported.
METHODS: This was a retrospective study of all biopsied ocular and periocular histiocytic lesions from two centers, King Khaled Eye Specialist Hospital (KKESH) and King Abdulaziz University Hospital (KAUH) in Riyadh, Saudi Arabia, from January 1993 to December 2018. The histopathological diagnosis was confirmed, and the cases were re-classified by reviewing all histopathological slides. The corresponding demographic and clinical data were analyzed. A relevant literature review was also carried out for comparison of our collected analyzed data to published data and to draw our own conclusions.
RESULTS: A total of 34 ocular/periocular histiocytic lesions in 28 patients who were mostly Saudis (92.9%) were included. The male-to-female ratio was 4:3. The median age at presentation was 6.4 years (range: 2.8-35 years). Twenty-two patients had unilateral involvement, and six patients had bilateral lesions. In patients with Langerhans cell histiocytosis (LCH; L group), the most common presenting findings were eyelid swelling (75%), periocular tenderness (37.5%), proptosis/globe displacement (37.5%) eyelid erythema (25%), and orbital pain (12.5%). In patients with Rosai Dorfman disease (RDD; R group), proptosis/globe displacement occurred in all patients and 80% had decreased vision. Patients in the C group (Cutaneous non-LCH histiocytoses) had variable clinical features because of the different locations of the histiocytic lesions, with the majority involving the eyelids (66.7%). Diagnosis was accurately reached clinically in 38.8%, 33.7%, and 46.7% of patients in the L, C, and R groups, respectively. Overall, the clinical diagnosis was in concordance with the histopathologic diagnosis in 14 out of 34 lesions (41.2%).
CONCLUSIONS: Histiocytic disease is more likely to be overlooked clinically owing to its rarity. In the C group, juvenile xanthogranuloma (JXG) was the most commonly encountered histiocytic lesion and had a tendency to present at a later age with extremely rare intraocular involvement in contrast to previously published reports. The median age at presentation was higher in group R. All patients in group L had strictly unilateral disease, while RDD (group R) was most commonly bilateral. Future research on genetic aspects, management, and prognosis is necessary.

Juvenile xanthogranuloma (JXG) is the most common form of non-Langerhans cell histiocytosis and oral mucosal involvement is exceedingly rare. Histiocytic disorders harbor activating mutations in MAPK pathway, including the report of BRAF V600E in JXG of extracutaneous site. However, no information is available for oral JXG. Herein, the clinicopathological and immunohistochemical features of five new oral JXG were evaluated in conjunction with literature review. Also, we assessed the BRAF V600E in oral samples. Five oral JXG were retrieved from pathology archives. Morphological and immunohistochemical analyses were performed. The BRAF V600E status was determined with TaqMan allele-specific qPCR. The series comprised of three female and two male patients, most of them adults, with a median age of 39 years (range 13-68 years). Clinically, the lesions appeared as asymptomatic solitary nodules, measuring until 2.5 cm, with more incident to the buccal mucosa. Morphologically, most of the cases presented classical histological features of JXG, with histiocytic cells consistent with the non-Langerhans cell immunophenotype. BRAF V600E was not detected in the cases tested. This is the first and largest published series of oral JXG affecting adults and a Brazilian population. The molecular pathogenesis of oral JXG remains unknown. Clinicians and pathologists must recognize JXG to avoid misdiagnoses with oral benign or malignant lesions.

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.

Juvenile Xanthogranuloma (JXG), the most common pediatric non-Langerhans cell histiocytosis, may rarely occur in association with Neurofibromatosis (types 1 and 2), Juvenile Myelomonocytic Leukemia and Cutaneous Mastocytosis (CM) and, morphologically, mimics Erdheim-Chester Disease tissue lesions and ALK-positive histiocytosis. We describe a 4-year-old girl with Beta-Thalassemia Major who developed an hypopharyngeal BRAFV600E- and ALK-negative JXG and CM. JXG has been rarely reported in the aerodigestive tract and in association with CM. In this molecular era, knowledge of genetic heterogeneity of JXG and clinical scenarios in which it may develop is essential for the appropriate diagnosis and treatment of each individual patient.

BACKGROUND: Neurofibromatosis type 1 (NF-1) predisposes individuals to the development of benign and malignant tumors. The association of NF-1, juvenile xanthogranuloma (JXG), and juvenile myelomonocytic leukemia has been described in the literature. It is unclear whether JXG alone constitute a risk factor for leukemia or other malignancies in children with NF-1.
OBJECTIVE: To determine if there is an association between NF-1, JXG, and malignancy.
METHODS: We conducted a retrospective case-control study comparing children with NF-1 and malignancy (cases) with sex- and age-matched children with NF-1 without malignancy (controls).
RESULTS: We identified 739 patients with NF-1 over a 20-year period, 14 of whom also had a diagnosis of malignancy. These cases include 9 (64%) boys and 5 (36%) girls. JXG were found in 4/14 (28.5%) cases and 6/29 (21%) controls (odds ratio 1.5, 95% confidence interval 0.35-6.6, P = .56).
CONCLUSIONS: Retrospective design, small number of cases, and inconsistent documentation of clinical findings, including age at disappearance of JXG.
CONCLUSIONS: Juvenile xanthogranulomas do not appear to confer an increased risk for malignancy in children with NF-1.