Eosinophilic granuloma (EG) is the most common form of Langerhans cell histiocytosis, presenting as a single osteolytic lesion of the calvarium. Its diagnosis is based on typical clinical and radiological features. While surgical resection has been the standard treatment for EG, growing evidence favors watchful waiting, as unifocal calvarial lesions appear to frequently undergo spontaneous remission. However, histopathological confirmations of this hypothesis are still very limited.
Methods. Here, we report a case of EG with typical clinical and radiological features which, due to intervening circumstances, was resected in a delayed fashion. Moreover, we perform a systematic review of the literature on conservative management of EG.
In our case, histological examination showed ongoing bone regeneration with no traces of the disease. Through our literature review, we found 47 cases of calvarial EG managed with watchful waiting. No active intervention was required in 43 cases (91%). Four patients (9%) received surgery or chemotherapy due to the persistence/progression of symptoms or family request. Three reports other than ours documented spontaneous disease remission in surgically resected EG upon histopathological examination.
Our report provides further evidence that watchful waiting can be a reasonable option in the management of single calvarial EG.

Langerhans cell histiocytosis (LCH) is an uncommon proliferative disease with an unknown cause. Its clinical manifestations vary and can involve a variety of organs. To diagnose LCH, radiographs, histopathological and immunohistochemical findings are essential. The gold standard for a definite diagnosis is positive CD1a/CD207 and S100 in the immunohistochemical results. Different treatment plans are available for patients struggling with LCH. To our knowledge, the LCH incidence rate is about 8.9 in one million children and 1-2 cases in one million adults. Our case shows the importance of early diagnosis of this rare condition for the prevention of any further spreading. This case report is about a 35-year-old male patient struggling with diabetes insipidus with a chief complaint of tooth mobility. Based on his X-ray radiographs, osteolytic lesions were found. A biopsy was performed, and due to histopathological and immunohistochemical findings, it was diagnosed as a case of LCH in adults. This paper shows that although the incidence rate of LCH is rare in adults, dealing with a patient struggling with diabetes insipidus and osteolytic bone lesions with an unknown cause, LCH must be taken into consideration. Due to the fact that LCH\'s first manifestations are mostly first oral, its good prognosis in the early stages, and if it progresses, it can turn fatal, it is important that dentists are aware of this disease, its clinical manifestations, and patient management. In case of suspicion, X-ray examination, biopsy, histopathological, and immunohistochemical exams must be performed.

BACKGROUND: Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD) are rare histiocytic disorders in the L (Langerhans) group diseases. They range from self-limited benign diseases to lethal disseminated forms.
METHODS: This retrospective study was conducted in 3 tertiary hospitals in Saudi Arabia and Brazil. Histopathological records were searched for all patients diagnosed with ocular and periocular histiocytic disorders from January 1993 to December 2018. Histopathological slides and medical files were reviewed for data collection and simple analysis of demographics, clinical manifestations, and management. The relevant literature is reviewed.
RESULTS: Twenty-two eyes of 18 patients with biopsy-proven histiocytic disorders in the L group were included. Female-to-male ratio was 1.25:1. Average age at presentation was 14 years (range, 1-54). LCH was diagnosed in 14 eyes, while eight eyes had ECD. All LCH cases were unilateral and confined to the bone as cases of eosinophilic granuloma (EG), while patients with ECD were bilateral. Commonest presentations in EG and ECD were eyelid swelling (85.7%) and periocular xanthomas (75%), respectively. Orbit was involved in 100% of EG cases, with bony erosion in 54.5%. Relevant systemic involvement was found in 100% of ECD and 21% of EG cases. Surgical intervention was needed in 16 of the 22 eyes (72.7%). All EG and 25% of patients with ECD required surgical excision.
CONCLUSIONS: Histiocytic disorders are a rare group of diseases, including the L group. Relevant systemic associations require specific and selective therapy. A high clinical index and multidisciplinary collaboration are essential for the proper evaluation and management of these patients.

BACKGROUND: The rare form and mildest variant of Langerhans cell histiocytosis is eosinophilic granuloma (EG). In the clinical presentation, EG can be monostotic, polyostotic, or can encompass many organs. The parietal bone is the most common location of the skull bones that are affected by EG. So far, there have been no reported cases of EG with skull odor as an unexplained presentation.
METHODS: An 8-year-old girl presented with a 4 months history of a right parietal bone swelling of the skull with an offensive odor. There was no discharge and no history of vomiting or trauma. An MRI scan of the brain showed swelling with a bone lesion of the right parietal bone. Infection was the source of the swelling and the bad odor. Treatment was done by surgical excision of the lesion.
CONCLUSIONS: EG has a variety of presentations and should be suspected when tenderness and local swelling are present. Radiography was found to be helpful in the diagnosis and surgical treatment was done to manage the case.

Eosinophilic granuloma is an unusual benign disease that usually affects the pediatric population and young adults. It is the most benign of the diseases traditionally known as histiocytosis X that are now called Langerhans cell histiocytosis.
Pediatric patient with a painful lump in the temporal region. The imaging tests carried out reveal the existence of an osteolytic lesion with an aggressive pattern compatible with eosinophilic granuloma. The patient underwent surgery with a conclusive definitive histological diagnosis of eosinophilic granuloma.
Eosinophilic granuloma can affect one or multiple bones, of which the most frequent are the cranial bones, epiphyses of long bones and ribs, requiring individualized diagnosis and treatment strategies for optimal management and results, with surgical treatment of First choice.
Eosinophilic granuloma is an infrequent benign condition that requires a correct anamnesis and clinical examination of the patient, as well as the demonstration of the characteristic radiological images, allowing a generally accurate presumptive diagnosis to be reached that in most cases can be considered definitive.
El granuloma eosinófilo es una enfermedad benigna poco usual que suele afectar a la población pediátrica y adultos jóvenes. Es la afección más benigna de las enfermedades tradicionalmente conocidas como histiocitosis X que en la actualidad reciben la denominación de histiocitosis de células de Langerhans.
Paciente pediátrico con bultoma doloroso en región temporal. Las pruebas de imagen realizadas ponen de manifiesto la existencia de una lesión osteolítica con patrón de agresividad compatible con granuloma eosinófilo. El paciente es intervenido mediante cirugía con diagnóstico histológico definitivo concluyente de granuloma eosinófilo.
El granuloma eosinófilo puede afectar a uno o múltiples huesos, de los cuáles los más frecuentes son los huesos craneales, epífisis de huesos largos y costillas, precisando estrategias de diagnóstico y tratamiento individualizadas para un manejo y resultado óptimo, siendo el tratamiento quirúrgico de primera elección.
El granuloma eosinófilo es un cuadro benigno infrecuente que requiere de una correcta anamnesis y exploración clínica del paciente, así como la demostración de las imágenes radiológicas características, permitiendo llegar a un diagnóstico de presunción generalmente certero que en la mayoría de ocasiones se puede considerar definitivo.

A histiocytosis is a group of immunoproliferative disorders of clonal cells. The management protocols are still evolving, with chemotherapy as the mainstay of treatment.
This study aims to evaluate the feasibility, safety, efficacy, and complication profile of stereotactic radiosurgery for intracranial histiocytosis.
The authors reviewed PubMed, Scopus, Web of Science, and Embase for \"radiosurgery\" and \"histiocytosis\" in the English/Japanese language following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The patient profile, radiosurgical parameters (dose and isodose), target volume, and mode of radiosurgery (Gamma knife, LINAC radiosurgery, etc.) were collected. Its use as primary or adjuvant therapy, clinical and radiological outcome was also evaluated.
We identified 7 studies (9 patients); mean age: 41.9 years (24-57 years). Six patients received Gamma-knife radiosurgery, whereas 3 received CyberKnife radiosurgery. The Langerhans cell histiocytosis variants were eosinophilic granuloma in 3, whereas 4 were not defined. Two cases had Rosai-Dorfman disease, and 2 different yet pathogenetically related histiocytic disorders. Four patients harbored lesions in the pituitary stalk and posterior pituitary, 2 patients in the petrous region, 1 patient had a pontine lesion, and 2 patients had multiple lesions. The dose delivered ranged from 8 to 28 Gy. A total of 18 lesions (9 patients) were followed for 81.67 patient-years: 7 (39%) disappeared, 8 (44.4%) showed radiological reduction, and 2 (11%) remained stable. One lesion (5%) showed an increase in size needed surgical excision. There were no adverse effects.
The role of stereotactic radiosurgery needs to be further evaluated as the current cohort with only 9 cases (2 are Rosai-Dorfman disease) is insufficient to make conclusions. It may be a viable alternative in localized disease, along with chemotherapy and targeted surgery.

BACKGROUND: The study aimed to identify, enlist, and analyze cases of unisystem LCH in the maxillofacial pediatric population to understand the clinical presentation and encourage the consideration of this rare disease in the differential diagnosis. Langerhans cell histiocytosis (LCH) is an aggressive benign condition affecting mainly the pediatric population. It can be easily masked as periodontal disease in the maxillofacial region. Early diagnosis and a systemic evaluation are of utmost importance.
METHODS: We are presenting a complete review of literature in the pediatric population according to PRISMA guidelines for clinicopathologic, histopathological, immunohistochemistry, and treatment for unisystem LCH. The risk of bias assessment across studies was done using a Case series appraisal checklist by Guo et al. 53 RESULTS: Forty-nine articles (152 cases) were selected which met our inclusion and exclusion criteria to be included in our review. Most of the patients fall in 6-12 years of age with the involvement of the mandibular body region in 40.79% cases. This disease mainly presents as erythematous gingiva, pain, swelling, and mobile teeth. Management can range from minimal intervention to chemotherapy and surgery.
UNASSIGNED: Although this is a rare condition, it should be considered especially in the pediatric population with periodontitis type lesions and floating teeth and comprehensive management should be followed. Early diagnosis of the disease is very important.

The various presentations of osseous Langerhans cell histiocytosis (LCH) make it difficult to distinguish from other bone diseases. In addition, there is no universally accepted protocol for managing osseous LCH for single non-central nervous system-risk lesions. Here, the rare cases of two paediatric patients, aged 1 and 2 years, who presented with a solitary tibial lesion at time of LCH diagnosis, are reported. One patient progressed to multiple lesions after curettage of the original lesion. Subsequently, both patients received preventive chemotherapy using the Taiwan Paediatric Oncology Group (TPOG) revised protocol for treating low risk patients with LCH, namely, TPOG LCH2002-LR. After receiving this treatment, which included a schedule of prednisolone and vincristine for 6 weeks, followed by prednisolone, vincristine and 6-mercaptopurine for a further 48 weeks, both patients are free from recurrence or progression.

BACKGROUND: Acetabular roof lesions (ARLs) in children are uncommon and may involve a variety of diseases. The acetabular roof is the main weight-bearing area of the hip joint, and lesions affecting the acetabular roof lead to fluid accumulation in the hip joint, causing hip pain and claudication. Methods for diagnosing and treating ARLs and the prognosis after treatment are rarely reported. We present our experience in a group of children and teenagers with ARLs to retrospectively explore the clinical and imaging features and histopathological diagnosis and report the treatment methods and follow-up observations.
METHODS: Patients with ARLs admitted to the Children\'s Hospital of Chongqing Medical University from April 2011 to September 2018 were selected retrospectively. We collected the basic information of patients (name, sex, age), main symptoms and signs, results of various laboratory tests, treatment methods, and intraoperative observations through the hospital medical record system. We collected X-ray, computed tomography (CT), magnetic resonance imaging (MRI) and pathological examination data through the Picture Archiving and Communications System. Follow-up data were collected through an outpatient medical record system, telephone, and chat software (such as WeChat). We used descriptive methods to analyze the lesion structure and destruction mode based on the imaging findings and histopathological diagnosis.
RESULTS: There were 14 ARL patients, including 6 with eosinophilic granuloma (EG), 5 with chronic osteomyelitis, 2 with bone cyst, and 1 with tuberculosis. One patient underwent percutaneous needle biopsy, 2 underwent open biopsy, and 11 underwent curettage; among them, 5 patients also underwent bone grafting. These lesions had no characteristic imaging findings, and the diagnosis was mainly based on histopathological examination. Most patients showed complete symptom resolution and good hip function at the 1-year follow-up.
CONCLUSIONS: ARLs are not common in children. The types of lesions are diverse and mostly benign, with EG being most common. Malignant tumors may also occur, such as Ewing\'s sarcoma, non-Hodgkin\'s lymphoma, metastases and neuroblastoma. CT and MRI can be helpful in diagnosing certain cases, but incisional biopsy is required in most cases.

We describe and illustrate herein a case of eosinophilic pulmonary granulomatosis (EPG) in a 16-mo-old, castrated male, Great Pyrenees crossbred dog. EPG appears to differ from eosinophilic pneumonias and eosinophilic bronchopneumopathy in dogs by the presence of nodules and masses in the lungs composed of eosinophils, macrophages, and various combinations of lymphocytes, plasma cells, neutrophils, and mast cells within fibrous tissue. Specific information from this dog was added to the information from the limited number of other dogs diagnosed with EPG reported in the veterinary literature, and the information analyzed. EPG appears to have no breed or sex predilection and tends to be a disease of younger dogs, often ≤ 3 y of age. Antemortem imaging of nodules and masses in the lungs, combined with cytologic evidence of eosinophils in the lesions, is highly suggestive of EPG, and the diagnosis can be confirmed postmortem. Concurrent eosinophilia and basophilia can be features of EPG, but their diagnostic value requires further investigation, as does the possible causal association with Dirofilaria immitis infection.