A wide spectrum of disorders involves the parotid glands, in infancy and childhood. Acute or chronic inflammatory/infectious diseases are predominant. The first branchial cleft anomalies are congenital lesions that typically manifest during childhood. Tumor lesions are more likely to be benign, with infantile hemangioma the most common in infancy and pleomorphic adenoma the most frequent in childhood. Malignant tumors are uncommon, with mucoepidermoid carcinoma the least rare. Infiltrative parotid diseases are rare and have some pediatric clinical specificities. These common and uncommon disorders of parotid glands during childhood and their imaging characteristics are reviewed.

We evaluated long-term outcomes of 288 children with refractory-Langerhans cell histiocytosis (R-LCH) from 26 countries, who were prescribed off-label MAPK inhibitors (MAPKis) according to clinical indications. MAPKi indications included 148 R-risk-organ–positive (R-RO+), 67 R-risk-organ–negative (R-RO–), 13 lung destruction (lung), 9 sclerosing cholangitis (SC), 49 neurodegeneration (ND), and 2 diabetes insipidus (DI) cases. Median ages at diagnosis and MAPKi onset were 1.3 and 2.3 years, respectively, with median follow-up of 3.7 years (1166 person-years). Agents mostly prescribed as monotherapies were 184 prescriptions of vemurafenib, 115 of dabrafenib, 3 of encorafenib, 42 of cobimetinib, 45 of trametinib, and/or 1 prescription of binimetinib; followed 51 times by various chemotherapies or hematopoietic stem-cell transplantation, or 28 times by combined anti-BRAF–anti-MEK. Short-term responses (<8 weeks) ranged from 98% (R-RO+ and R-RO–), to 30% (lung) to none (ND, DI, and SC); although long-term lung and ND responses could be observed. Skin rash was the most frequent adverse event (∼55%), and 7 others included 1 case of cardiomyopathy and 6 of retinitis. Five developed MAPKi-unrelated tumors and 9 patients died. Five-year survival was 98%. After 113 patients with R-LCH discontinued MAPKi, 69 experienced disease reactivation. None of the various empirical maintenance therapies were able to prevent secondary reactivation. Among the 143 assessable patients without ND-LCH at MAPKi onset, 60 developed ND (45%, 5-year risk). MAPKis appeared to be safe and effective in children with R-RO+/RO–LCH, whereas other indications’ responses were less frequent or occurred later. Further studies are needed to find effective maintenance-therapy approaches, particularly to prevent frequently observed secondary ND.

Background: Juvenile Xanthogranuloma (JXG) is a non-Langerhans cell histiocytosis, occurring mainly in infancy. With an extracutaneous lesion, its diagnosis is difficult, because of a wide clinical spectrum. Here we demonstrate and characterize imaging features of 11 patients with JXG of the head and neck in various locations. Material and Methods: We recorded clinical data and reviewed all imaging studies of 11 patients with JXG of the head and neck. Ultrasonography (US) alone was performed in 1 patient; MRI alone in 6 patients; US and MRI in 1 patient; and US, CT, and MRI in 3 patients. We evaluated the following characteristics in all studies: location and number of lesions, echogenicity and vascularization on US, density on CT, signal intensity on T₁- and T₂-weighted images, ADC and enhancement on MRI, and tumor boundaries and bone involvement. Results: Lesions were well-defined in 9 cases, and bone erosion was present in 2. On US, lesions were hypoechoic or hyperechoic and with or without vascularization. On CT, lesions were hyper-dense, with no calcification. On MRI, lesions were mildly hyper-intense or iso-intense on T₁-weighted images in 8 of 9 patients, hypo-intense on T2-weighted images in 7 of 10, low ADC in 7 of 9, and enhancement in 7 of 7. Conclusions: The diagnosis of extra cutaneous JXG may be proposed, with the following suggestive criteria: age < 1 year, well-defined lesion, mild hyper-intensity on T₁-weighted images, hypo-intensity on T₂-weighted images, low ADC, enhancement, and possible adjacent bone involvement.

Reason to report Aicardi-Goutières syndrome is a rare congenital multisystem disease of genetic origin, and its manifestations resemble those of an intrauterine infection; therefore, TORCH infection (toxoplasmosis, others, rubella, cytomegalovirus, herpes) is its main differential diagnosis. The classic brain imaging features—leukoencephalopathy, striatal necrosis, intracranial calcifications and atrophy—are well known. Recently, another radiological pattern characterized by large-vessel stenosis, including moyamoya syndrome, and ischaemic lesions, has been reported, mainly with SAMHD1 mutation. What was unique We report a case of a moyamoya syndrome from this unusual cause, in a young child. Ramification of this report The radiologist must be aware of such arterial anomalies, which are poorly reported in the radiological literature, and search for them when performing brain magnetic resonance for Aicardi-Goutières syndrome, even in the absence of a genetic diagnosis. Moreover, in an infant or young child with moyamoya syndrome, Aicardi-Goutières syndrome should be included in the differential diagnoses.

Pneumoparotid is a rare cause of parotid swelling characterized by the presence of air in the Stensen's duct and/or the parotid gland. In children, it is often self-inflicted, due to psychiatric disorder or recreational habits (puffing the cheeks, blowing balloons, bruxism…). The diagnosis may be suggested by specific signs such as crepitus or foamy saliva flowing from the Stensen's duct. Here, we present 2 cases of involuntary self-inflicted pneumoparotid, diagnosed by ultrasound and CT, in a child and a teenager. Imaging is useful for diagnosis and excluding complications. Ultrasonography may be sufficient to make the diagnosis of pneumoparotid but is less sensitive than CT. CT can make the diagnosis, but also more completely explores the deep cervical spaces and the thorax, especially important in cases with respiratory symptoms. Treatment is usually conservative, in association with behavioral counselling or psychologic/psychiatric therapy, to avoid activities leading to intra oral pressure increase.