A case report of multicentric reticulohistiocytosis with atypical cutaneous presentation.

Multicentric reticulohistiocytosis (MRH) is a rare systemic disorder characterized by histiocytic hyperplasia that mainly involves the skin, mucous membranes, and joints. The typical clinical features include papules, nodules, and arthritis. MRH lesions are relatively extensive but small and scattered. Joint inflammation is characterized by diffuse symmetric polyarthritis as the first symptom, which can be severe and disabling due to destructive joint changes. MRH is easily misdiagnosed in clinical practice. Here, we report the case of an elderly male patient who presented with polyarticular pain in the hip and interphalangeal joints as the first manifestation, followed by the development of large, isolated, bulging skin nodules, which are atypical MRH lesions. This is rare in all MRH case reports, and we made the correct diagnosis by combining skin histopathology, immunohistochemistry, and other clinical examinations. We performed surgical treatment on the local skin lesions of this patient. This case suggests that clinicians should actively correlate the condition and accurately diagnose MRH when encountering atypical skin changes or other diseases as the first symptom and explore the mechanisms of MRH and other clinical manifestations.

Histiocitosi en pediatria: la gran simuladora / Histiocitosis en pediatría: la gran simuladora / Histiocytosis in pediatrics: the great simulator

Fonament. La histiocitosi de cèl·lules de Langerhans (HCL) és una malaltia caracteritzada per l’acumulació anormal decèl·lules del sistema monociticomacrofàgic, amb una presentació clínica molt variable. Sovint, atesa la gran variabilitat clínica d’aquesta entitat, es fan diagnòstics tardansque repercuteixen en el pronòstic.Objectiu. Descriure les principals manifestacions clíniquesde l’histiocitosi de cèl·lules de Langerhans (HCL) en unhospital de tercer nivell els darrers catorze anys. Mètode. Estudi observacional, descriptiu i retrospectiu delscasos d’HCL tractats a l’Hospital Universitari Vall d’Hebron.Criteris d’inclusió: edat dels participants (de 0 dies fins a 18anys), període d’estudi (2006-2021) i diagnòstic de la malaltia, basat en el diagnòstic clínic o la confirmació histològica. Mitjançant la revisió d’històries clíniques es van registrar variables demogràfiques (edat i sexe), clíniques (formade presentació, manifestacions inicials, evolució i recaigudes) i troballes rellevants en les proves complementàries. Resultats. Es van revisar 55 casos diagnosticats d’HCL. Lamitjana d’edat de presentació va ser 4,5 anys (RI 1-8), ambpredomini del sexe masculí (3:1). El motiu de consulta mésfreqüent ha estat l’aparició d’una tumoració (20%, sobretota la zona cranial), seguit per dolor ossi (14,5%), polidípsiai poliúria (9,1%), torticoli (9,1%), coixesa, exantema cutanii febre (7,3% cadascuna). Basant-nos en la classificacióLCH-IV, la majoria es van classificar com a unisistèmiques(71%) enfront de les multisistèmiques (29%). Conclusions. L’HCL és una malaltia poc freqüent en pediatria, però amb un espectre clínic ampli que comportadiagnòstics tardans associats a complicacions. Té molta importància conèixer aquesta entitat i les seves manifestacionsprincipals. (AU)

Fundamento. La histiocitosis de células de Langerhans (HCL) es una enfermedad caracterizada por la acumulación anormal de células del sistema monocítico-macrofágico, con una presentación clínica muy variable. A menudo, dada la gran variabilidad clínica de esta entidad, se realizan diagnósticos tardíos que repercuten ensu pronóstico. Objetivo. Describir las principales manifestaciones clínicas de la histiocitosis de células de Langerhans (HCL) en un hospital de tercer nivel en los últimos 14 años. Método. Estudio observacional, descriptivo y retrospectivo de los casos de HCL tratados en el Hospital Universitario Vall d’Hebron. Criterios de inclusión: edad de los participantes (de 0 días de vida hasta 18 años), período de estudio (2006-2021) y diagnóstico dela enfermedad, basado en el diagnóstico clínico o la confirmación histológica. Mediante la revisión de historias clínicas, se registraron variables demográficas (edad y sexo), clínicas (forma de presentación, manifestaciones iniciales, evolución y recaídas) y hallazgos relevantes en las pruebas complementarias. Resultados. Se revisaron 55 casos diagnosticados de HCL. La media de edad de presentación fue 4,5 años (RI 1-8), con predominio del sexo masculino (3:1). El motivo de consulta más frecuente ha sido la aparición de una tumoración (20%, sobre todo a nivel craneal), seguido por dolor óseo (14,5%), polidipsia y poliuria(9,1%), tortícolis (9,1%), cojera, exantema cutáneo y fiebre(7,3% cada una). Basándonos en la clasificación LCH-IV, la mayor parte se clasificaron como unisistémicas (71%) frente a las multisistémicas (29%). Conclusiones. La HCL es una enfermedad poco frecuente en pediatría pero con un amplio espectro clínico que comporta diagnósticos tardíos asociados a complicaciones. Resulta de gran importancia conocer a esta entidad y sus principales manifestaciones. (AU)

Background. Langerhans cell histiocytosis (LCH) is a disease characterized by the abnormal accumulation of cells of the monocytemacrophage system. Its clinical presentation is highly variable, which can lead to late diagnosis and worse outcomes.Objective. To describe the main clinical manifestations of LCH in atertiary hospital in the last 14 years. Method. Observational, descriptive, and retrospective study of children with LCH treated at the Hospital Universitari Vall d’Hebron.Inclusion criteria: age of the participants (0 days of life and up to18 years), study period (2006-2021) and diagnosis of the diseasebased on clinical diagnosis or histological confirmation. We recorded demographic variables (age and sex), clinical characteristics(form of presentation, initial manifestations, evolution, and relapses), and relevant findings in diagnostic tests. Results. 55 children diagnosed with LCH were reviewed. The meanage at presentation was 4.5 years (IR 1-8), with a predominanceof males (3:1). The most frequent reason for consultation was the appearance of a lump (20%, especially at the cranial level), followed by bone pain (14.5%), polydipsia and polyuria (9.1%), torticollis (9.1%), and limping, skin rash, and fever (7.3% each). Based on the LCH-IV classification, most were classified as singlesystem (71%) versus multi-system (29%). Conclusions. LCH is a rare disease in pediatrics but with a wideclinical spectrum that can lead to late diagnoses and subsequentcomplications. It is of great importance to know this entity and itsmain manifestations. (AU)

Multicentric Reticulohistiocytosis (Mrh): A Case Report On A Rare Destructive Arthritis.

Multicentric Reticulohistiocytosis is a rare disorder of unknown aetiology which affects skin and joints predominantly. There are no specific laboratory investigations for diagnosis. Diagnosis can be made clinically and on a histopathological basis. There is no consensus on treatment. We report a case from Pakistan with classical presentation who did well on methotrexate and low dose steroids. Prompt diagnosis and early treatment may save from significant disability.

Multicentric reticulohistiocytosis with eosinophilic gastroenteritis: An unusual relationship.

Multicentric reticulohistiocytosis (MRH) is a rare disease with poorly defined therapeutic strategies. Here, we report the case of a patient with eosinophilic gastroenteritis who developed MRH after 5 years. The patient presented with disabling and rapidly progressive polyarthralgia, eosinophilic gastroenteritis, and resistance to first-line therapies. However, there was a marked improvement in the arthritis symptoms following treatment with tofacitinib. This presentation provides a useful perspective for the therapeutic management of complex scenarios involving MRH.

Clinical characteristics of multicentric reticulohistiocytosis and distinguished features from rheumatoid arthritis: a single-center experience in China.

OBJECTIVE: To investigate the clinical features of multicentric reticulohistiocytosis (MRH). METHODS: The clinical manifestations, laboratory examination results and histologic characteristics of eleven patients with MRH were collected and compared with those of 33 patients with rheumatoid arthritis. RESULTS: In total, 72.7% of the MRH patients were women. The median age was 46 years (range 33-84 years). Diagnosed by specific pathologic features, all MRH patients exhibited cutaneous involvement. The dorsa of the hands, arms, face and auricle were the most commonly affected areas. Nodules were also located on the legs, scalp, trunk, neck, and even the hypoglossis and buccal mucosa. Ten MRH patients (90.9%) had symmetric polyarthritis. Compared with rheumatoid arthritis (RA) patients, MRH patients were more likely to have distal interphalangeal joint (DIP) involvement (63.6% vs 24.2%, P = 0.017) and less likely to have elbow (36.4% vs 72.7%, P = 0.003), ankle (45.5% vs 93.9%, P < 0.001) and metacarpophalangeal joint (MCP) (36.4% vs 78.8%, P = 0.009) involvement. Positivity for rheumatoid factor (RF) (36.4% vs 84.6%, P = 0.001) and anti-CCP antibody (9.1% vs 81.8%, P = 0.000), as well as the median RF titer [43.8 (31.7-61.0) vs 175.4 (21.3-940.3), P = 0.021], in MRH patients was lower than in RA patients. Elevation of the erythrocyte sedimentation rate (ESR) was also less common in MRH patients than in RA patients (36.4% vs 72.7%, P = 0.030). After treatment with median- to large-dose corticosteroids and disease-modifying antirheumatic drugs, 8 patients achieved complete remission and 2 patients partial remission (skin lesions ameliorated, joint lesions not ameliorated). CONCLUSION: Always pathologically diagnosed, MRH is a systemic disease involving RA-like erosive polyarthritis and a specific distribution of skin nodules characterized by "coral beads". More DIP involvement and less elbow, ankle and MCP involvement are seen in MRH than in RA. In addition, less positivity and lower-titer RF, uncommon presence of anti-CCP antibodies and ESR elevation may be helpful to distinguish MRH from RA.

A Rare Case of Pediatric Xanthoma Disseminatum With Diabetes Insipidus and BRAF p.V600E Mutation.

ABSTRACT: Xanthoma disseminatum (XD) is a rare non-Langerhans cell histiocytosis characterized by xanthomatous lesions in the absence of hyperlipidemia. XD usually develops in young adults, and there are rare cases among children. BRAF mutations are frequent in Langerhans cell histiocytosis and Erdheim-Chester disease but absent or only rarely detected in other histiocytosis. Herein, we described a 6-year-old Chinese girl presented with generalized skin lesions and diabetes insipidus for 5 months. There were multiple periorbital xanthelasma with histopathological features of foamy histiocytes infiltration with Touton cells. Pituitary magnetic resonance imaging showed pituitary enlargement and pituitary stalk thickening. The presence of BRAF p.V600E mutation makes this case distinctive and also offers a potential therapeutic target. According to our review of the literature, this is the first pediatric XD with diabetes insipidus and BRAF mutation.

Skin Manifestation Associated With Multicentric Reticulohistiocytosis.

ABSTRACT: Multicentric reticulohistiocytosis (MRH) is a rare multisystem disorder, primarily affecting the skin and joints. As severe joint damage is a possible symptom, early diagnosis and therapeutic intervention are required. Cutaneous lesions present with characteristic features such as discrete reddish nodules, especially on acral locations. Additionally, the face, scalp, trunk and extremities are also affected. Xanthomatous plaques are also seen on the face. The cutaneous manifestations of MRH are various, which therefore should be differentiated from several diseases. In particular, MRH has been reported to assume clinical appearances resembling Gottron papules, periungual erythema, V-neck erythema, shawl sign, and poikiloderma associated with dermatomyositis. Histopathologic features show proliferation of multinucleated giant cells with abundant eosinophilic granular ground glass-like cytoplasm in the dermis. Multicentric reticulohistiocytosis is occasionally paraneoplastic and is associated with internal malignancies. The appropriate therapies are still challenging, and oral prednisolone, immunosuppressants, and recent biologics are used. In this article, cutaneous lesions, histopathology, and pathogenesis of MRH are mainly discussed from a dermatological perspective. It is important, not only for dermatologists but also for rheumatologists and orthopedists, to be able to distinguish between the various types of skin lesions brought on by MRH. Cutaneous signs are important diagnostic clues and assessment tools for therapeutic efficacy.

Multicentric reticulohistiocytosis masquerading as cutaneous connective tissue disease.

Multicentric reticulohistiocytosis (MRH) is a rare type of non-Langerhans cell histiocytosis characterized by coral-toned papules with predilection for dorsal surfaces in addition to severe arthropathy. It sometimes proves difficult to differentiate these joint and skin findings clinically from certain rheumatologic diseases, primarily dermatomyositis. Herein, we present an 82-year-old woman who presented with the clinical findings described above and was subsequently diagnosed with MRH after biopsy and review of relevant clinical history. Because about 25% of patients diagnosed with MRH have an underlying occult malignancy, our patient underwent a complete malignancy workup that was negative. She was treated with systemic corticosteroids and methotrexate, which resulted in an improvement of the arthritis and constitutional symptoms. This case demonstrates that in patients with both rheumatologic and dermatologic symptoms, particularly on acral surfaces, MRH must be a diagnostic consideration. Identifying this disease early in its course can prevent negative consequences for the patients, specifically arthritis mutilans and upper airway involvement.