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Introduction: Rosai-Dorfman Disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is an uncommon histiocytic disorder. It may be associated with autoimmune diseases, but there are few reports of concurrent ankylosing spondylitis. RDD is typically characterized by massive bilateral and painless cervical lymphadenopathy, which can also involve extranodal sites and constitutional symptoms, but rarely affect the chest cavity. Case presentation: In this report, we present a case of a patient with a suspicious invasive anterior mediastinal lesion affecting multiple blood vessels and adjacent tissues. The patient has a history of ankylosing spondylitis. Despite extensive radiological and interventional examinations, the possibility of malignancy could not be completely ruled out. Following surgical resection of the tumor, the final pathology diagnosis suggested RDD. Conclusion: Our report emphasizes the importance of considering RDD in the differential diagnosis of invasive thoracic malignancies. Thoracoscopy or mediastinoscopy biopsy can improve diagnostic accuracy. Our study contributes to an improved understanding among clinicians regarding the diagnosis and treatment of intrathoracic RDD and provides relevant evidence for future exploration of potential associations between RDD and ankylosing spondylitis. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman disease (RDD) is a rare heterogeneous disorder of non–Langerhans cell histiocytosis. The patient is a 24-year-old woman who presented with a 1-month history of polydipsia, polyuria, and 25-lb (11.3-kg) weight loss over 6 months and was found to have significantly elevated 24-hour urine volume (8.4 L). Prior to completion of the work-up for her presenting symptoms, she returned with a new complaint of disabling back pain and bilateral lower-extremity numbness with weakness refractory to conservative treatment. Magnetic resonance imaging (MRI) showed a prominent T2 to T4 stenosis from a soft tissue mass. Due to progressive pain and accelerating neurological symptoms, she was admitted for surgical debulking and biopsy. In the 10 hours she was unable to drink fluids surrounding her procedure, her serum sodium climbed to 160 mmol/L (reference interval, 137-145 mEq/L; [137-145 mmol/L]). Urine testing and desmopressin challenge revealed arginine vasopressin deficiency (AVP-D), formerly known as central diabetes insipidus. Pituitary MRI showed a mildly enlarged pituitary gland with loss of normal posterior pituitary signal supporting the diagnosis. Epidural mass pathology showed predominant histiocytes indicating RDD. This case highlights the diverse clinical manifestations of RDD and is an unusual instance of RDD linked with AVP-D and neurological involvement. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman disease (RDD) is a rare benign proliferative disorder. Lymph nodes are the usual and common sites of involvement. Involvement of the extranodal site is also documented in the literature. 18F-fluorodeoxyglucose positron emission tomography computed tomography (F18-FDG PET CT) is a valuable whole-body imaging modality in staging and treatment response of various lymphoproliferative and solid organ malignancy. Similarly, PET CT survey can detect the involved sites of various body systems, infective or inflammatory diseases, and provide guidance for biopsy and to reach to diagnosis. Here, we present a case of RDD, who presented with neurological manifestations and on F18-FDG PET CT, diagnosed with multiorgan involvement. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman (RDD) is a rare histiocytic syndrome with variable clinical characteristics and extranodal involvement in more than 43% of the patients. This mini-review presents an overview of the literature on Rosai-Dorfman disease. The histological features and the current understanding of the management and prognosis are discussed. A case of a 61-year-old patient with a rare diagnosis of Rosai-Dorfman disease is also presented, as well as the process of its setting and treatment. The diagnosis is set by extensive radiologic and interventional procedures, including multiple biopsies, morphological examinations, and imaging techniques. Most important for the diagnosis appeared to be the pathology showing characteristic features of Rosai-Dorfman disease in the intra-abdominal lymph nodes performed twice showing characteristic extensive fibrosis. In addition, multiple dilated sinuses were filled with macrophages and histiocytes while the immunohistochemical examination pointed very likely to RDD with increased amount of plasma cells. [ABSTRACT FROM AUTHOR]

Rarely, Rosai–Dorfman disease (RDD) manifests exclusively in the skin, typically as nodules on the trunk and extremities. Recognition of characteristic histopathologic features enables diagnosis of RDD. A 55‐year‐old female presented with a 7‐year history of cutaneous nodules involving the trunk and extremities. A prior skin biopsy specimen at a different institution had demonstrated a dense dermal lymphohistiocytic infiltrate with histiocytes containing GMS+ forms, favored to represent cryptococcal organisms, with a differential diagnosis including other infections with parasitized histiocytes. Despite antibiotic therapy, lesions persisted. After a presentation to our institution, a biopsy specimen showed a diffuse infiltrate, including histiocytes with voluminous pale cytoplasm with focal emperipolesis of inflammatory cells and S100 immunohistochemical positivity. Clinical and radiologic examinations did not identify significant extracutaneous involvement. A genetic study performed on the biopsy specimen identified a K57Q mutation of MAP2K1. The presence of this mutation correlated with prior reports of MAP2K1 mutation in classic RDD, thereby supporting our histopathologic diagnosis of RDD over an infectious process and further illuminating options for targeted therapies. At 3‐year follow‐up, the patient has been managed with a course of systemic corticosteroids and excision of bothersome lesions. Consideration of systemic therapy is ongoing. [ABSTRACT FROM AUTHOR]

BRAF V600E mutations are frequently found in histiocytic/dendritic cell neoplasms such as Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis (LCH), but few reports have also described BRAF mutations in Rosai-Dorfman disease (RDD), and even these cases may predominantly represent mixed histiocytosis. BRAF mutations have been studied in histiocytic/dendritic cell neoplasms and described to be associated with increased risk of relapse and long-term consequences, but few studies have examined BRAF V600E mutation in RDD, which is recognized as a neoplasm given the high frequency of MAPK pathway alterations. Here, we report a case of BRAF V600E-mutated RDD in a patient who presented with generalized lymphadenopathy. During our evaluation of this patient, we also found expression of PD-L1 in neoplastic histiocytes. During our review period, only few cases of RDD reported to harbor BRAF mutation or were evaluated for the expression of PDL1 by neoplastic cells. Given the potential challenges in distinguishing RDD from other histiocytic/dendritic cell neoplasms, including mixed histiocytosis with similar clinicopathological manifestations, we will discuss the current state of knowledge regarding the frequency and clinical impact of BRAF V600E in RDD, as well as the role of BRAF mutations in RDD pathogenesis. Distinction of BRAF V600E mutated histiocytic/dendritic cell neoplasms requires consideration of distinctive histopathological and immunophenotypic findings in appropriate clinical and radiologic setting. Given the increasing use of BRAF inhibitors as well as checkpoint blockade inhibitors to treat a number of cancers, we will discuss the clinical implications of the presence of BRAF V600E mutation and PD-L1 expression in RDD. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman disease (RDD) with craniocervical junction involvement is a rare clinical entity. We present herein a case of a pediatric patient with craniocervical junction RDD which was surgically treated. A 10-year-old female with a history of B-cell acute lymphoblastic leukemia (B-ALL) in remission and RDD presented with frontal migraine headaches. She previously had a right posterior chest wall lesion which was biopsy-proven RDD. She was found on imaging to have a dural-based right craniocervical junction lesion. Given her history of B-ALL, after a multidisciplinary discussion, the decision was made to proceed with resection with possible initiation of cobimetinib or clofarabine. The patient underwent a suboccipital craniotomy, C1 laminectomy, and resection of the dural-based lesion. Gross total resection was achieved, and histopathology confirmed the diagnosis of RDD. She was discharged home on postoperative day 4. No recurrence was seen on follow-up imaging at 3 months. We conducted a systematic literature review examining all cases of pediatric intracranial RDD and all cases of craniocervical junction RDD. This represents, to the best of our knowledge, only the second case of pediatric craniocervical junction RDD. Although RDD is often self-limiting, medical treatment is often considered for intracranial disease, but tissue confirmation is necessary. Surgical resection provides histopathologic diagnosis and can sometimes serve as definitive treatment for a particular lesion. [ABSTRACT FROM AUTHOR]

Recent advances in Rosai-Dorfman-Destombes disease (RDD), notably molecular testing, targeted therapy, and PET-CT imaging, hold promise for better recognition and improved outcomes. This study presents patients diagnosed and treated in a "real world" setting, where navigating limited resources must be considered. This retrospective single-center review includes 15 adult patients diagnosed with RDD at Vancouver General Hospital between November 2015 and October 2023. The cohort comprised five males and ten females with a median age 53 years (range 19–80 years). All 15 patients had extra-nodal disease; 11 patients exclusively had extra-nodal disease, and four patients also had lymph node involvement. Seven patients had tissue next-generation sequencing, identifying MAP2K1 mutations in four cases and a KRAS p.K117N mutation in one case that was treated with targeted therapy using trametinib. PET-CT was used for disease staging in four cases. Six patients with refractory disease tolerated lenalidomide and dexamethasone without significant toxicity; three patients achieved complete response, and three had partial response. This study highlights RDD's diverse extra-nodal manifestations. Lenalidomide combined with dexamethasone is an effective and well-tolerated treatment option for select patients, especially those with refractory disease. Broad utilization of NGS and PET-CT can positively influence management decisions. [ABSTRACT FROM AUTHOR]

Histiocytic neoplasms (HNs) in adults have been reported to be associated with a high prevalence of coexisting haematological and solid malignancies. While a proportion of coexisting HNs and haematological malignancies share identical genetic alterations, the genetic association between HNs and solid malignancies has scarcely been reported. We report a case of Rosai–Dorfman disease (RDD) complicated by coexisting clear cell sarcoma (CCS). RDD is a rare HN. CCS is an ultrarare soft tissue sarcoma with a poor prognosis. Mutation analysis with whole‐exome sequencing revealed six shared somatic alterations including NRAS p.G12S and TP53 c.559+1G>A in both the RDD and CCS tissue. This is the first evidence of a clonal relationship between RDD and solid malignancies using mutational analysis. We hypothesise that neural crest cells, which originate in CCS, are likely the common cells of origin for RDD and CCS. This case helps to unravel the underlying clinicopathological mechanisms of increased association of solid malignancies in HNs. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Abstract Introduction Rosai-Dorfman Disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is an uncommon histiocytic disorder. It may be associated with autoimmune diseases, but there are few reports of concurrent ankylosing spondylitis. RDD is typically characterized by massive bilateral and painless cervical lymphadenopathy, which can also involve extranodal sites and constitutional symptoms, but rarely affect the chest cavity. Case presentation In this report, we present a case of a patient with a suspicious invasive anterior mediastinal lesion affecting multiple blood vessels and adjacent tissues. The patient has a history of ankylosing spondylitis. Despite extensive radiological and interventional examinations, the possibility of malignancy could not be completely ruled out. Following surgical resection of the tumor, the final pathology diagnosis suggested RDD. Conclusion Our report emphasizes the importance of considering RDD in the differential diagnosis of invasive thoracic malignancies. Thoracoscopy or mediastinoscopy biopsy can improve diagnostic accuracy. Our study contributes to an improved understanding among clinicians regarding the diagnosis and treatment of intrathoracic RDD and provides relevant evidence for future exploration of potential associations between RDD and ankylosing spondylitis.

An uncommon benign histiocytic illness, Rosai-Dorfman disease (RDD) mostly affects lymph nodes but can also manifest as extranodal involvement. We describe a case of a female patient, sixty years of age, who had joint discomfort, sleeplessness, weight loss, and headache and eye problems. A heterogeneously hypodense perirectal mass was seen on imaging. Other histiocytic diseases, metastatic cancer, and lymphoma were among the differential diagnosis. Through biopsy and immunohistochemistry staining, which revealed S-100 and CD68 positivity with CD1a negative, a definitive diagnosis of RDD was made. Over a 2-year period following surgical excision, the patient's symptoms significantly improved and there was no sign of recurrence. This example emphasizes the significance of taking RDD into account when making a differential diagnosis for perirectal tumors and the function of imaging in conjunction with histological testing in guiding management.

Abstract Background Rosai–Dorfman disease (RDD)/sinus lymphohistiocytosis is a rare benign lymphoproliferative disorder. Only 25% show extra-nodal manifestation, only 5% are seen involving the CNS, with intraventricular manifestation rarely reported. Our aim was to highlight important imaging features which would be useful in considering this entity as one of the differentials while encountering this rare entity. Case description We present a case of a 34-year-old female with complaints of headache, altered behavior and visual disturbances. MRI brain showed T2 hypointense lesion arising from the left choroid plexus with dense homogenous enhancement, with multiple additional extra-axial dural-based lesions and a small lesion involving right choroid plexus. Left parietal craniotomy was done, and the lesion was excised. Histopathology showed large foamy macrophages in eosinophilic background, with lymphophagocytosis (emperipolesis), confirming the diagnosis of Rosai–Dorfman disease. Conclusions Intraventricular Rosai–Dorfman disease is a rare entity. Imaging features of T2 hypointense homogenously enhancing lesion with blooming on GRE, without features of calcification or hemorrhage, may be helpful in prompting adequate histopathologic evaluation.

Objective To investigate the clinical manifestations, imaging, clinicopathological, immunohistochemistry, treatment and prognosis of intracranial primary Rosai-Dorfman disease (RDD). Methods The clinical data of a patient with intracranial primary RDD admitted to The First Affiliated Hospital of Xinjiang Medical University were analyzed retrospectively, and the relevant literature were reviewed. Results The magnetic resonance imaging of the head showed an occupying lesion on the left parietal temporal area, and surgery was performed to completely remove the lesion. Postoperative pathology was diagnosed as RDD, immunohistochemistry showed S-100(+), CD68(+). Conclusions RDD is a benign disease, and its diagnosis is mainly based on pathology and immunohistochemistry. Surgical resection is currently the most effective treatment for RDD. For multiple or unresectable lesions, radiotherapy and chemotherapy can be given as an adjunct. [ABSTRACT FROM AUTHOR]

Rosai‐Dorfman disease (RDD) is characterized by clonal proliferation of S‐100 positive histiocytes and variable emperipolesis. It commonly affects cervical lymph nodes. Central nervous system (CNS) involvement is extremely rare. We attempted to evaluate the Cyclin D1 expression and frequency of KRAS and BRAF mutations in the RDD involving the CNS. All patients with histopathologically diagnosed RDD involving CNS were recruited from 2011 to 2022. All cases were subjected to immunohistochemistry for CD68, CD163, S100, CD1a, GFAP, CD207, EMA, ALK, BRAFV600E, IgG4, IgG, and CyclinD1. The real‐time polymerase chain reaction (RT‐PCR) for hotspot mutation analysis of KRAS (exons 2, 3, and 4) and BRAF (V600E) was conducted on formalin‐fixed paraffin‐embedded tissue using a commercial kit (EntroGen). A total of seven cases were included. The median age was 31 years, with six men and one woman. It showed spinal cord (n = 4) and intracranial (n = 3) involvement. Histologically, all cases showed histiocyte‐rich inflammation with evidence of emperipolesis. These histiocytes were positive for S100, CD68, CD163, and Cyclin D1, whereas negative for CD1a, CD207, and EMA. BRAF V600E was expressed in a single case. None of the control cases (demyelination and infarction) with histiocytic infiltrate showed Cyclin D1 expression. Four RDD cases showed increased IgG4‐positive plasma cells (>10/HPF) and IgG4/IgG ratio (>40%). BRAF V600E mutation was detected in one case (14.28%), while none showed KRAS mutation. RDD involving CNS is extremely rare and diagnostically challenging. Nuclear Cyclin D1 expression along with S‐100 positivity in the tumor cells is a strong diagnostic clue. BRAF and KRAS mutations are rare in CNS RDD. [ABSTRACT FROM AUTHOR]

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Background: Rosai–Dorfman disease (RDD)/sinus lymphohistiocytosis is a rare benign lymphoproliferative disorder. Only 25% show extra-nodal manifestation, only 5% are seen involving the CNS, with intraventricular manifestation rarely reported. Our aim was to highlight important imaging features which would be useful in considering this entity as one of the differentials while encountering this rare entity. Case description: We present a case of a 34-year-old female with complaints of headache, altered behavior and visual disturbances. MRI brain showed T2 hypointense lesion arising from the left choroid plexus with dense homogenous enhancement, with multiple additional extra-axial dural-based lesions and a small lesion involving right choroid plexus. Left parietal craniotomy was done, and the lesion was excised. Histopathology showed large foamy macrophages in eosinophilic background, with lymphophagocytosis (emperipolesis), confirming the diagnosis of Rosai–Dorfman disease. Conclusions: Intraventricular Rosai–Dorfman disease is a rare entity. Imaging features of T2 hypointense homogenously enhancing lesion with blooming on GRE, without features of calcification or hemorrhage, may be helpful in prompting adequate histopathologic evaluation. [ABSTRACT FROM AUTHOR]

This article explores the use of cladribine (2-CdA) as a potential treatment for Rosai-Dorfman disease (RDD), a rare condition characterized by painless lymph node enlargement. The article presents case studies of adult patients with RDD who were treated with 2-CdA, showing that it can effectively reduce lymphadenopathy and improve symptoms. However, the treatment can also have severe side effects, such as bone marrow aplasia. The article suggests that 2-CdA should be reserved for patients with life-threatening or refractory RDD. [Extracted from the article]

BackgroundRosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a rare non-malignant disorder characterized by excessive proliferation of histiocytes, the cause of which remains unknown. Although the lymph nodes are the most commonly affected site, some patients may present with extranodal involvement, particularly in the skin, nasal cavity, eyes, and bones. In this report, we aim to present a unique case of RDD with pleural involvement in a 61-year-old patient. To our knowledge, only a few cases of RDD primarily manifesting as pleural disease have been reported thus far.Case summaryA 61-year-old male with left brachial plexus neuropathy was found to have a space-occupying lesion in the left posterior pleura. Initial chest CT showed a 5.7cm × 1.3cm soft tissue density shadow, which grew to 6.8cm × 1.7cm two years later. Given a history of clear cell renal cell carcinoma, pleural metastasis was suspected. The patient declined a needle biopsy but underwent surgical excision. Postoperative pathology and immunohistochemistry confirmed Rosai-Dorfman disease (RDD). After surgery, the patient received anti-infection, phlegm reduction, rehydration, and analgesia treatments and recovered well.ConclusionRDD originating in pleura is rare, its clinical and imaging manifestations lack specificity, and it is easy to be misdiagnosed. It is crucial to consider the possibility of RDD when encountering nodular pleural masses or lamellar soft tissue lesions. Differential diagnosis should include pleural mesothelioma, pleural metastases, solitary fibrous neoplasms, and schwannomas of the pleura. Ultimately, a definitive diagnosis can be achieved through pathology and immunohistochemistry analysis.

Rosai-Dorfman (RDD) is a rare histiocytic syndrome with variable clinical characteristics and extranodal involvement in more than 43% of the patients. This mini-review presents an overview of the literature on Rosai-Dorfman disease. The histological features and the current understanding of the management and prognosis are discussed. A case of a 61-year-old patient with a rare diagnosis of Rosai-Dorfman disease is also presented, as well as the process of its setting and treatment. The diagnosis is set by extensive radiologic and interventional procedures, including multiple biopsies, morphological examinations, and imaging techniques. Most important for the diagnosis appeared to be the pathology showing characteristic features of Rosai-Dorfman disease in the intra-abdominal lymph nodes performed twice showing characteristic extensive fibrosis. In addition, multiple dilated sinuses were filled with macrophages and histiocytes while the immunohistochemical examination pointed very likely to RDD with increased amount of plasma cells.

The article discusses cutaneous involvement in Rosai-Dorfman disease (RDD), a rare non-Langerhans cell histiocytosis. The study describes the clinical, dermoscopic, and therapeutic features of cutaneous RDD (CRDD) based on nine cases identified in North Africa. The article emphasizes the importance of recognizing characteristic features of CRDD, such as asymptomatic red-brown to yellow papules, nodules, or plaques, and highlights the use of dermoscopy in aiding diagnosis. Treatment options for CRDD include systemic corticosteroids, with observation being indicated in some cases of remarkable remission. [Extracted from the article]

Histiocytic disorders mostly occur as de-novo nodal or extranodal benign masses with rare secondary malignant transformation. A 10-year-old female presented with 10-cm cervical swelling since 9 months associated with fever. Computed tomography revealed left cervical lymphadenopathy and bilateral lung nodules. Lymph node excision biopsy showed effacement of architecture by atypical histiocytes with marked nuclear pleomorphism and frequent mitosis. Focal areas showed mature histiocytes with emperipolesis. The cells were immunopositive for CD68, CD163, and S100 (focal), whereas they were negative for Langerin and CD1a. The Ki67 proliferative index was 30%. A diagnosis of histiocytic sarcoma in a background of Rosai-Dorfman disease was made.

Abstract Neurologic Rosai–Dorfman disease (RDD) is a rare type of non-Langerhans cell histiocytosis that affects the central nervous system. Most neurologic RDDs grow like meningiomas, have clear boundaries, and can be completely resected. However, a few RDDs are invasive and aggressive, and no effective treatment options are available because the molecular mechanisms involved remain unknown. Here, we report a case of deadly and glucocorticoid-resistant neurologic RDD and explore its possible pathogenic mechanisms via single-cell RNA sequencing. First, we identified two distinct but evolutionarily related histiocyte subpopulations (the C1Q+ and SPP1+ histiocytes) that accumulated in the biopsy sample. The expression of genes in the KRAS signaling pathway was upregulated, indicating gain-of-function of KRAS mutations. The C1Q+ and SPP1+ histiocytes were highly differentiated and arrested in the G1 phase, excluding the idea that RDD is a lympho-histio-proliferative disorder. Second, although C1Q+ histiocytes were the primary RDD cell type, SPP1+ histiocytes highly expressed several severe inflammation-related and invasive factors, such as WNT5A, IL-6, and MMP12, suggesting that SPP1+ histiocytes plays a central role in driving the progression of this disease. Third, oligodendrocytes were found to be the prominent cell type that initiates RDD via MIF and may resist glucocorticoid treatment via the MDK and PTN signaling pathways. In summary, in this case, we report a rare presentation of neurologic RDD and provided new insight into the pathogenic mechanisms of progressive neurologic RDD. This study will also offer evidence for developing precision therapies targeting this complex disease.

Rosai Dorfman disease (RDD) is a rare non-Langerhans histiocytic disorder, which belongs to the R group of the 2016 revised histiocytic classification. It's characterized by the accumulation of activated histiocytes in the sinusoids of lymph nodes and/or extranodal tissues. Herein, we report a 7-year-old female who was initially suspected to have a lymphoma but was later identified as having RDD. She presented with a history of fever, night sweats, and weight loss, and on physical examination had bilateral cervical lymphadenopathy. Histologic examination of the biopsied cervical lymph nodes showed distended sinuses with S100 and CD68 immunoreactive histiocytes demonstrating emperipolesis, confirming a diagnosis of RDD. The condition is known to be self-limiting. However, evidence from literature and our case management shows that medical therapy can hasten remission in pediatric cases. [ABSTRACT FROM AUTHOR]

Background: Rosai–Dorfman disease (RDD) is an uncommon proliferative histiocytic disorder involving lymph nodes and various organs. Forty-three percent of RDD cases originate from extranodal sites; however, RDD rarely arises from the colon. Case presentation: A 75-year-old man was admitted to our hospital because of intra-abdominal masses that were incidentally detected during surveillance by computed tomography (CT) after treatment for lung cancer. Enhanced CT showed two mass lesions located in the cecum to the appendix (diameter, 40 mm) and around the sigmoid colon (diameter, 24 mm). Positron emission tomography (PET)-CT revealed an apparent uptake of fluorodeoxyglucose. Intraluminal endoscopy did not reveal definite mucosal abnormalities. These findings suggest the presence of malignant neoplasms including gastrointestinal stromal tumors, lung cancer metastasis, and malignant lymphoma. Exploratory laparoscopy and/or tumor excision were planned to obtain a definitive diagnosis. Based on laparoscopic findings, ileocecal resection and sigmoidectomy were simultaneously performed to excise the tumors. Postoperative histopathological examination revealed multiple RDD originating from the mesocolon side of the cecum and the sigmoid colon. The patient did not receive any adjuvant therapy. No recurrence was observed one year after surgery. Conclusion: RDD originating from the colon is extremely rare. Tumor extirpation or organ resection is sometimes required to obtain a definitive diagnosis of RDD, and minimally invasive surgery is helpful. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman-Destombes disease (RDD) is a rare non-Langerhans cell histiocytosis (LCH) disorder characterized by systemic extranodal lesions. Common cases include skin lesions, whereas liver lesions are rare. This study presents a case of a 66-year-old woman with a solitary extranodal liver lesion who underwent successful surgical treatment followed by glucocorticoid therapy. The patient did not experience any symptoms before surgery. The liver lesion was incidentally discovered during a routine ultrasound examination. Enhanced CT scan revealed the lesion with the characteristic of washout, similar to primary hepatic cancer (HCC). CT scans of the head, neck, chest, and abdominal pelvis revealed no lymph node or other organ lesions. After surgery, the liver lesion was diagnosed as RDD, and subsequent whole-body examinations did not reveal any skin lesions. The definitive diagnosis was solid liver RDD in adults. Although there were no typical cases of bilateral cervical lymph node lesions, ultrasound and CT examinations promptly detected liver lesions, leading to the correct diagnosis through surgical resection. The findings from this case indicate that RDD can occur in rare extrasegmental areas, and the imaging characteristics of liver lesions are not specific, indicating the importance of avoiding delayed diagnosis. [ABSTRACT FROM AUTHOR]

Rosai–Dorfman disease (RDD) is a rare non-malignant disorder, characterized by painless multiple cervical lymphadenopathy, fever, and elevated inflammatory markers. Its diagnosis is difficult due to its rare incidence and various clinical presentations, especially in extranodal involvement. In this report, we demonstrate a patient with RDD who presented with a nasal septum and laryngeal tumor that caused dyspnea. We achieved a successful treatment outcome with combined surgical resection of the laryngeal mass and corticosteroid medication. The symptoms and tumors were resolved within 3 weeks after treatment. We reported our experiences with review of literatures. [ABSTRACT FROM AUTHOR]

Purpose: Histiocytosis is one of the most challenging diseases in medical practice. Because of the broad spectrum of clinical manifestations, systemic involvements, unknown etiology, and complex management, different types of histiocytosis are still a big question mark for us. Orbital histiocytosis is characterized by the abnormal proliferation of histiocytes in orbital tissues. It could affect the orbit, eyelid, conjunctiva, and uveal tract. Orbital histiocytosis can cause limited eye movement, proptosis, decreased visual acuity, and epiphora. In this study, we review the novel findings regarding the pathophysiology, diagnosis, and treatment of different types of histiocytosis, focusing on their orbital manifestations. Method: This review was performed based on a search of the PubMed, Scopus, and Embase databases or relevant published papers regarding orbital histiocytosis on October 9th, 2023. No time restriction was proposed, and articles were excluded if they were not referenced in English. Results: 391 articles were screened, most of them being case reports. The pathophysiology of histiocytosis is still unclear. However, different mutations are found to be prevalent in most of the patients. The diagnostic path can be different based on various factors such as age, lesion site, type of histiocytosis, and the stage of the disease. Some modalities, such as corticosteroids and surgery, are used widely for treatment. On the other hand, based on some specific etiological factors for each type, alternative treatments have been proposed. Conclusion: Significant progress has been made in the detection of somatic molecular changes. Many case studies describe various disease patterns influencing the biological perspectives on different types of histiocytosis. It is necessary to continue investigating and clustering data from a broad range of patients with histiocytosis in children and adults to define the best ways to diagnose and treat these patients. [ABSTRACT FROM AUTHOR]

Rosai–Dorfman disease (RDD) or sinus histiocytosis with massive lymphadenopathy can present with or without systemic disease. It is a benign histioproliferative disorder characterized by generalized lymphadenopathy, weakness, anemia, and rarely extranodal involvement. While RDD most commonly affects lymph nodes, extranodal involvement of multiple organs has been reported, including the central nervous system (CNS). However, CNS involvement in RDD is rare and is not well characterized. Isolated involvement of the fourth ventricle is even rarer. Such lesions may be mistaken for intraventricular tumors such as ependymoma or medulloblastoma. This report highlights the necessity to consider RDD as a differential diagnosis in case of intraventricular space-occupying lesion. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Intracranial RDD is rare medical event mimicking different diagnoses. Although the surgical resection is the best treatment option, but radiation therapy can also achieves long‐term suboptimal outcomes. An 83‐year‐old male with a history of tension‐type headaches was evaluated. He was conscious with no focal neurological deficits. His brain MRI revealed an enhancable bifrontal tumor originating from falx cerebri and superior sagittal sinus dura. Due to the patient's preference and decline for gross total resection, she underwent a stereotactic biopsy. The pathology was positive for Rosai–Dorfman diseases. He received definitive targeted radiation with a total dose of 4500 cGy administered in 200 cGy daily fractions. His 4‐year follow‐up showed regional tumor control with excellent neurological outcome. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman-Destombes (RDD) disease is also known as sinus histiocytosis with massive lymphadenopathy. It is an uncommon heterogeneous disease of children and young adults. Most of the patients with RDD generally present with painless lymphadenopathy, while extranodal and multisystem manifestation of the disease is unusual. The diagnosis is based on the imaging with clinicopathological correlation. Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography is useful for the initial staging of the RDD lesions, which have similar appearance and avidity like intermediate and high-grade lymphomas. Here, we present the case of a 55-year-old female presented with left breast mass that turned out to be the extranodal Rosai-Dorfman disease. [ABSTRACT FROM AUTHOR]

Neurologic Rosai–Dorfman disease (RDD) is a rare type of non-Langerhans cell histiocytosis that affects the central nervous system. Most neurologic RDDs grow like meningiomas, have clear boundaries, and can be completely resected. However, a few RDDs are invasive and aggressive, and no effective treatment options are available because the molecular mechanisms involved remain unknown. Here, we report a case of deadly and glucocorticoid-resistant neurologic RDD and explore its possible pathogenic mechanisms via single-cell RNA sequencing. First, we identified two distinct but evolutionarily related histiocyte subpopulations (the C1Q+ and SPP1+ histiocytes) that accumulated in the biopsy sample. The expression of genes in the KRAS signaling pathway was upregulated, indicating gain-of-function of KRAS mutations. The C1Q+ and SPP1+ histiocytes were highly differentiated and arrested in the G1 phase, excluding the idea that RDD is a lympho-histio-proliferative disorder. Second, although C1Q+ histiocytes were the primary RDD cell type, SPP1+ histiocytes highly expressed several severe inflammation-related and invasive factors, such as WNT5A, IL-6, and MMP12, suggesting that SPP1+ histiocytes plays a central role in driving the progression of this disease. Third, oligodendrocytes were found to be the prominent cell type that initiates RDD via MIF and may resist glucocorticoid treatment via the MDK and PTN signaling pathways. In summary, in this case, we report a rare presentation of neurologic RDD and provided new insight into the pathogenic mechanisms of progressive neurologic RDD. This study will also offer evidence for developing precision therapies targeting this complex disease. [ABSTRACT FROM AUTHOR]

Abstract Background Sinus histiocytosis with massive lymphadenopathy, also known as Rosai-Dorfman disease, is a rare, self-limiting disease that predominantly affects children and young adults. Moreover, the disease is characterized by painless bilateral cervical lymphadenopathy in 95% of the patients. However, few reports are available on the Rosai-Dorfman disease of the thymus. Case presentation We report a rare case of thymic Rosai-Dorfman disease detected using computed tomography. During a medical examination, a 50-year-old man underwent a chest computed tomography scan, which revealed an anterior mediastinal single mass with fat in the thymus. A thymectomy was performed to completely remove the tumor using a thoracoscopic technique due to a clinical suspicion of thymoma. Furthermore, Rosai-Dorfman disease was confirmed using histological and immunohistochemical analyses. Conclusions To the best of our knowledge, this is the sixth case of thymus-affecting solitary Rosai-Dorfman disease with histological and immunohistochemical evidence. Fat in the thymus, as was present in this case, has never been described in Rosai-Dorfman disease previously. Our results highlight the challenge of diagnosing this uncommon tumor before surgery, and more cases need to be reported to help with the preoperative diagnosis of such a rare tumor.

Abstract Background Rosai-Dorfman Disease (RDD) is a rare self-limiting histiocytosis, more prevalent in children and young adults. It typically manifests as painless bilateral massive cervical lymphadenopathy but may also extend to extra-nodal sites, with intrathoracic RDD noted in 2% of cases. Distinguishing mediastinal RDD from thymoma on imaging poses challenges, underscoring the reliance on pathological features and immunohistochemical staining for diagnosis. Case presentation Patient, male, 33 years old, underwent lung a CT revealing an enlarged round soft tissue shadow in the anterior superior mediastinum, compared to a year ago. Surgical resection removed the entire mass, thymus, and part of the pericardium, confirming RDD on pathology. Genetic testing using second-generation testing technology identified a KRAS gene point mutation. Conclusions No established treatment protocol currently exists for this disease. However, as genetic mutation research progresses, a novel therapeutic avenue is emerging: targeted therapy integrated with surgical interventions.

Rosai–Dorfman disease is the most frequent variant of non-Langerhans cell histiocytosis. Local forms can be resected or irradiated. If the process involves multiple organs, systemic chemotherapy can cure some patients. This article includes literature review and a case report of a 34-year-old patient with multifocal, multisystemic form of Rosai–Dorfman disease with bone and pleural involvement. The diagnosis was based on histological, immunohistochemical, and molecular studies of tumor tissue. Since November 2021, 6 courses of chemotherapy with cladribine and 8 infusions of zolendronic acid were carried out with achievement of durable remission. The tolerance was acceptable.

This study presents a rare case of Rosai-Dorfman disease (RDD) with nasal and nasopharyngeal involvement, illustrating the complexities in diagnosing this enigmatic histiocytic disorder. RDD, characterized by massive, painless cervical lymphadenopathy, poses diagnostic challenges due to its diverse clinical presentations. In this case, a 38-year-old woman presented with a year-long history of neck swellings, nasal congestion, headaches, and sinusitis-like symptoms. Radiological imaging and histopathological examination revealed RDD involvement in the nasopharynx and paranasal sinuses. RDD diagnosis was confirmed through immunohistochemistry. The patient's unique symptoms emphasize the importance of considering RDD in the differential diagnosis of sinonasal masses with recurrent or unusual complaints. This case underscores the need for increased awareness, multidisciplinary management, and further research to enhance understanding and treatment of RDD, especially in extranodal presentations.

Abstract Background Tumor-like lesions of the trachea are rare and challenging in diagnosis and management. Inflammatory myofibroblastoma, also known as Inflammatory pseudo tumors (IPTs), as well as Rosai Dorfman Disease (RDD) are inflammatory lesions that may involve the central airways with variable non-specific clinical features mimicking tumors. Case presentation In this study 2 cases with tumor-like lesions are presented. One case with an inflammatory pseudotumor and the other one with Rosai–Dorfman disease affecting the upper trachea. Both cases were successfully managed with tracheal resection anastomosis. Conclusion Tracheal Inflammatory myofibroblastoma, and Rosai–Dorfman diseases are rare tumor like lesions that present with upper airway obstruction. Despite being benign, these lesions may have features suggestive of malignancy, requiring prompt management. Complete surgical excision by segmental resection and primary anastomosis (if feasible) is the treatment of choice with an optimum outcome.

Rosai-Dorfman disease is an inflammatory non-neoplastic disease characterized by a histiocytic infiltrate in a polymorphous inflammatory background. It is typically presents in lymph nodes; cutaneous manifestation is uncommon. We present a case of cutaneous Rosai-Dorfman disease with classic cytomorphological and immunohistochemical features with a discussion around prognosis, follow-up and molecular testing. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman Disease is a rare benign disorder involving overproduction of immune cells, causing swollen lymph nodes and, in rare cases, the sternum. The sternal involvement may cause chest pain and masses. Diagnosis is confirmed through clinical examination, biopsy, and imaging. Treatment options may include surgery, radiation, or steroids. In this case study, we present an unusual example of extranodal Rosai-Dorfman Disease involving the sternum, bilateral clavicles and first three ribs, and pectoral muscle with no associated lymphadenopathy or systemic symptoms in a 57-year-old female. The etiology, pathology, immunohistochemistry, imaging findings, and treatment options of this unique disease are discussed. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman disease (RDD) is a benign histiocytosis with unknown etiology. It generally occurs in cervical lymph nodes. Isolated central nervous system (CNS) RDD is very rare in the literature. We reported a case of no systemic involvement Rosai-Dorfmann which is rarely seen and shows CNS involvement by mimicking meningioma. A 32-year-old man presented with diplopia and a headache he has been experiencing for the past two years. His neurological examination showed left facial paresthesia, consistent with trigeminal nerve trace. Tendon reflexes were increased at the right side and the right plantar reflex was extensor. Brain magnetic resonance imaging demonstrated irregularly shaped, tumorlike lesions in the bilateral cerebellopontin area that were compressing pons. Rosai-Dorfman disease can be differentiated from IgG4 related disease (IgG4-RD) by its characteristic features such as plasma cell density and emperipolesis seen in its histopathology. Rosai-Dorfman disease can be confused with other diseases radiologically and histopathologically, especially the IgG4-RD, so be careful about differential diagnosis. [ABSTRACT FROM AUTHOR]