Langerhans cell histiocytosis in the mandibular condyle and ramus. Endoscopic diagnosis. Case report / Histiocitosis de células de Langerhans en cóndilo y rama mandibular. Diagnóstico por vía endoscópica. Reporte de un caso

Langerhans cell histiocytosis (LCH) is a rare disease caused by uncontrolled proliferation and accumulation of immature bone marrow-derived myeloid dendritic cells. It is common in the pediatric population under 15 years of age and usually affects bones such as the skull, femur and mandibular body. This study presents the case of a 6-year-old female patient, with a bone lesion in the right mandibular ramus and condyle at an unusual location. A sample of the pathological tissue was taken by intraoral endoscopy to avoid comorbidities and esthetic sequelae. After a joint medical evaluation, the lesion was diagnosed as a monofocal LCH with special site involvement, establishing a single systemic treatment with indomethacin, as opposed to the chemotherapy regimen recommended by the International Histiocyte Society, in order to reduce the adverse effects of the latter. Two months after the beginning of the pharmacological treatment, reosification of the affected area was observed, with no recurrences after the end of the treatment. (AU)

La histiocitosis de células de Langerhans (LCH) es una afección rara originada por proliferación y acumulación descontrolada de células dendríticas mieloides inmaduras derivadas de la médula ósea. Su presentación es común en población pediátrica menor a 15 años, y suele afectar a huesos como el cráneo, fémur y cuerpo mandibular.En esta publicación se presenta el caso de un paciente de género femenino de 6 años, con lesión ósea en rama y cóndilo mandibular derecho de localización poco frecuente. Destaca la toma de muestra del tejido patológico mediante vía endoscópica intraoral con el fin de evitar comorbilidades y secuelas estéticas. Después de una evaluación médica conjunta, se diagnosticó como LCH monofocal con compromiso de sitio especial, estableciendo un tratamiento único de forma sistémica con indometacina, diferente a la quimioterapia recomendada por la Sociedad Internacional de Histiocitosis, de tal forma que disminuya los efectos adversos de esta. Se observó a los 2 meses de iniciado el tratamiento farmacológico reosificación de la zona afectada y sin recidivas posterior al término de este. (AU)

Unusual sites of bone involvement in Langerhans cell histiocytosis: a systematic review of the literature.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disease that originates from the uncontrolled proliferation and accumulation of bone marrow-derived immature myeloid dendritic cells. Dendritic cells are a type of histiocyte that play an important role in the human immune system and are found in the bone, skin, stomach, eyes, intestines, and lungs. OBJECTIVE: This systematic review aimed to collect and report published case reports of rare bone disease caused by LCH to avoid misdiagnoses or delays in diagnosis. METHODS: We systematically searched Scopus, PubMed, Embase, and Web of Sciences from August 1, 2000 to December 31, 2019. Studies reporting cases of LCH with rare bone involvement were included. RESULTS: We identified 60 articles including 64 cases. Of the identified cases, 31 (48.4%) involved children, and 33 (51.6%) involved adults. Additionally, 46.9% (30 individuals) were from Asian countries. The mean age of the children was 7.6 ± 4.3 years and that of the adults was 36 ± 12 years. The findings indicated that unifocal bone involvements were the most prevalent form of the disease (68.7%), and, overall, the skull and chest wall were the most commonly affected bones in both adults and children. The spine and long bones were the second most commonly affected bones in children, and the spine and jaw were the second most commonly affected bones in adults. Pain and swelling were the most frequent presenting signs among the investigated cases, and loss of consciousness, myelopathy, nerve palsy, visual loss, torticollis and clicking sounds were rare signs. Osteolytic lesions were the most frequent radiologic feature (62.5%), and intracranial hemorrhage, fluid-fluid level, dura and intracranial extension and pathologic fractures were rare radiological features. Total excision, curettage and observation in the unifocal group of patients and systemic chemotherapy in the other groups (i.e., multifocal and multisystem) were the most frequent management approaches. The recovery rates of the unifocal and multifocal groups were 77.3% and 81.8%, respectively, while that of the multisystem group was 55.5%. The rates of recurrence and mortality in the multisystem group were 11% and were higher than those in the other groups. CONCLUSIONS: LCH is a rare disease that can affect any organ in the human body. However, bone is the most commonly involved organ, and rare bone involvements may be the first or only symptom of the disease due to the rarity of such lesions; a lack of familiarity with them may result in misdiagnosis or delayed diagnosis.