Common progenitor origin for Rosai-Dorfman disease and clear cell sarcoma.

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.

A maxillary location of extra-nodal Rosai Dorfman disease: a case report.

Introduction: Rosai-Dorfman disease (RDD) is a rare benign histiocytic proliferation, characterized by a group of clinical symptoms. This report presents a case of extranodal RDD manifesting as a progressively enlarging left maxillary mass in a 42-year-old woman. Surgical exploration and biopsy confirmed the diagnosis of RDD, with characteristic histopathological features including emperipolesis. Treatment involved corticotherapy, resulting in controlled maxillary pain and improvement of the disease after one year. This case underscores the potential for extra-nodal RDD presentations, posing diagnostic challenges and emphasizing the importance of considering RDD in the differential diagnosis of maxillary masses.

Emperipolesis in pleural fluid mesothelial cells. A phenomenon not associated with Rosai-Dorfman disease, report of a case.

Emperipolesis is a cell-within-cell phenomenon distinct from phagocytosis more often described in Rosai-Dorfman disease, where usually lymphocytes or other bone marrow cells (plasma cells, erythroblasts or neutrophils) are entirely surrounded but not engulfed by macrophages as the host cell, but occasionally megakaryocytes and neoplastic could be. Mesothelial cell has been described in a couple of cases of lymphomas affecting serous membranes, but never described in pleuritis. In the present work, the first case of emperipolesis by mesothelial cells in a patient with self-limited pleural effusion was demonstrated by immunohistochemistry and Electron Microscopy studies.

Management of intracranial Rosai-Dorfman disease: An institutional experience.

OBJECTIVE: Rosai-Dorfman disease (RDD) is a rare benign proliferative disorder of histiocytes. The study discusses the intracranial RDD approach, its management, and its outcome. METHODS: It is a retrospective study performed in a tertiary center, the National Institute of Mental Health and Neuroscience, Bangalore, from January 2010 to December 2022. The biopsy-proven patients of RDD were recruited in the present cohort. Demographic and surgical details were collected from the record section, and radiology was collected from the internal storage system. Follow-up assessments were done clinically and telephonically. RESULTS: A total of 25 patients matched the criteria. The mean age was 32 ± 13.4 years, with male predominance. We have included only cranial cases (N=25). Among the intracranial lesions, 5/25 (20 %) patients had multicentric lesions. All the lesions were avidly enhancing on contrast, and 16 (64 %) lesions were hypointense on T2. Perilesional edema (T2/Flair hyperintensities in the surrounding white matter) was seen in 12 (48 %) patients. Gross total resection (GTR) was carried out in six (24 %) cases. Sub-total resection was in 14 (56 %), and biopsy was in five cases (20 %). Nineteen patients received adjuvant therapy, either only steroid (40 %), only low-dose radiotherapy (16 %), only Chemotherapy (4 %), or a combination of both. At follow-up,44 % of patients had stable disease,28 % had primary disease or recurrence growth, and regression in 12 % of cases. CONCLUSION: We demonstrate that surgical resection is an effective therapy for treating isolated intracranial RDD. Adjuvant therapy is an add-on treatment for skull base locations in multicentric locations or surgically inaccessible locations.

Cutaneous Rosai-Dorfman disease: a systematic review and reappraisal of its treatment and prognosis.

Cutaneous Rosai Dorfman disease (CRDD) is a rare histiocytic disorder that shows distinctive clinical presentation and prognosis. Sufficient data is currently lacking regarding evidence-based management of CRDD. This systematic review aims to provide a comprehensive overview of CRDD, focusing on treatment approaches and outcomes. PubMed and Scopus databases were searched for studies on CRDD from June 1st, 2013 to May 31st, 2023. Articles describing cases of CRDD confirmed with histological examination were eligible for inclusion. All interventions for CRDD were analyzed. The primary outcome measure was the response of cutaneous lesions to treatment including complete response (CR), partial response (PR), and no response. The secondary outcome measures were mortality rate, relapse rate, and the occurrence of adverse events related to CRDD treatment. Eighty-seven articles describing 118 CRDD cases were included. The mean age was 48.2±16.8 years. The sex ratio (F/M) was 1.53. Nodular (46.6%) erythematous (45.3%) lesions, located on the face (38.1%) were the most prevalent presentations. Associated hematological malignancies were noted in 8 (6.8%) cases. Surgical excision was the most prevalent intervention (51 cases) with CR in 48 cases. Systemic corticosteroids were used in 32 cases with 20 CR/PR, retinoids in 10 cases with 4 CR/PR, thalidomide in 9 cases with 5 CR/PR, methotrexate in 8 cases with 7 CR/PR while observation was decided in 10 cases with 6 CR/PR. Factors independently associated with the absence of response to treatment were facial involvement (OR = 0.76, p = 0.014), and cutaneous lesion size (OR = 1.016, p = 0.03). This systematic review shows distinctive clinical characteristics of CRDD and provides insights into the appropriate management of the disease. It allowed a proposal of a treatment algorithm that should be interpreted in the context of current evidence and would help practitioners in treating this rare disease.

Thymic Rosai-Dorfmann disease: a case report.

BACKGROUND: Rosai-Dorfman disease (RDD), known as sinus histiocytosis with massive lymphadenopathy, commonly involves lymph nodes in the neck or mediastinum, although extranodal involvement is observed in approximately 40% of RDD patients. RDD involving only the thymus has rarely been reported. Here, we report a case of RDD originating in the thymus. The lesion was surgically removed, and a cure was finally achieved. There was no recurrence after telephone follow-up for 3 years. CASE PRESENTATION: A 52-year-old male was accidentally found to have a 7 × 6 cm anterior mediastinum lump by chest computed tomography (CT). The mediastinal lesion was resected by surgery, and postoperative pathology revealed RDD originating from the thymus. Regular telephone follow-up after surgery lasted 3 years and showed that the patient remained in good condition without any relevant symptoms. CONCLUSIONS: RDD originating in the thymus cannot be characterized from CT images and is easily misdiagnosed as a traditional mediastinal tumor. This is mainly because there is so little disease in this area that physicians are not aware of it. We report this case with the hope that clinicians will have a better understanding of this disease. According to our follow-up results, surgery is an effective means of treatment.

Single-cell analysis of a progressive Rosai-Dorfman disease affecting the cerebral parenchyma: a case report.

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.

Mixed histiocytic disorders: Nature versus nurture?

Histiocytic diseases arise from MAPK mutations in myeloid progenitors. Depending on whether the progenitor follows a dendritic cell or macrophage/monocyte lineage the final histology results in Langerhans cell histiocytosis, Rosai-Dorfman disease or Erdheim-Chester disease. Commentary on: Friedman et al. Mixed histiocytic neoplasms: A multicentre series revealing diverse somatic mutations and responses to targeted therapy. Br J Haematol 2024;205:127-137.

An unusual presentation of unifocal Rosai-Dorfman disease and surgical treatment.

Rosai-Dorfman disease (RDD) is a rare histiocytic disorder with an unclear aetiology, and commonly presents with painless, bilateral cervical lymphadenopathy. Extranodal presentation in the absence of nodal involvement has been reported to have a predilection for the head and neck with less than 20 cases involving the jaw bones and sinuses. We present an interesting case of unifocal RDD of the infratemporal space in the absence of nodal involvement in a 61-year-old female treated with surgical excision and adjuvant radiation therapy.

A rare case of facial cutaneous Rosai-Dorfman disease clinically mimicking basal cell carcinoma followed by multiple myeloma after 2 years.

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytosis disorder characterized by the proliferation of histiocytes within the lymph nodes. Extranodal involvement can occur; however, only 10% of extranodal RDD involve the skin. We present a unique case of a 66-year-old woman with cutaneous RDD followed by the development of multiple myeloma (MM). To our knowledge, this is only the second reported case where RDD preceded a diagnosis of MM, with the first documented instance occurring in 2018. The patient presented to the dermatology clinic with a 5-year history of painless, solitary lesion over the right cheek. Local examination revealed a single 6 mm x 7 mm well-circumscribed pearly telangiectatic lesion resembling basal cell carcinoma over the right nasolabial fold and cheek. The lesion was excised with a 3 mm circumferential margin. Histopathology showed a mixed lymphohistiocytic cell infiltrate with emperipolesis and immunohistochemical staining patterns consistent with RDD. Two years later, the patient presented with hip pain and was diagnosed with MM. She was treated with lenalidomide, bortezomib, and dexamethasone, and was later maintained on lenalidomide. Our case adds to the limited evidence suggesting a potential association between RDD and MM. Further research in this field is required to promptly identify and manage patients with such a presentation in the future.

Mixed histiocytic neoplasms: A multicentre series revealing diverse somatic mutations and responses to targeted therapy.

Histiocytic neoplasms are diverse clonal haematopoietic disorders, and clinical disease is mediated by tumorous infiltration as well as uncontrolled systemic inflammation. Individual subtypes include Langerhans cell histiocytosis (LCH), Rosai-Dorfman-Destombes disease (RDD) and Erdheim-Chester disease (ECD), and these have been characterized with respect to clinical phenotypes, driver mutations and treatment paradigms. Less is known about patients with mixed histiocytic neoplasms (MXH), that is two or more coexisting disorders. This international collaboration examined patients with biopsy-proven MXH with respect to component disease subtypes, oncogenic driver mutations and responses to conventional (chemotherapeutic or immunosuppressive) versus targeted (BRAF or MEK inhibitor) therapies. Twenty-seven patients were studied with ECD/LCH (19/27), ECD/RDD (6/27), RDD/LCH (1/27) and ECD/RDD/LCH (1/27). Mutations previously undescribed in MXH were identified, including KRAS, MAP2K2, MAPK3, non-V600-BRAF, RAF1 and a BICD2-BRAF fusion. A repeated-measure generalized estimating equation demonstrated that targeted treatment was statistically significantly (1) more likely to result in a complete response (CR), partial response (PR) or stable disease (SD) (odds ratio [OR]: 17.34, 95% CI: 2.19-137.00, p = 0.007), and (2) less likely to result in progression (OR: 0.08, 95% CI: 0.03-0.23, p < 0.0001). Histiocytic neoplasms represent an entity with underappreciated clinical and molecular diversity, poor responsiveness to conventional therapy and exquisite sensitivity to targeted therapy.

A rare presentation of Rosai-Dorfman disease involving the central nervous system.

A 29-year-old gentleman diagnosed with Rosai-Dorfman disease (RDD) on corneal biopsy, 2 years ago, presented with fluctuating left-sided numbness, intermittent slurred speech, and urinary incontinence, progressively worsening over the past three months.

A rare presentation of Rosai-Dorfman-Destombes disease with central nervous system involvement and cutaneous wounds.

OBJECTIVE: The aim of this case report is to investigate an uncommon presentation of Rosai-Dorfman-Destombes (RDD) disease, and discuss possible differential diagnoses and treatment options for this pathology. RDD is a rare disorder of histiocytes that typically presents in patients as painless cervical lymphadenopathy. However, this case involves a patient with the central nervous system (CNS) type of RDD who later developed cutaneous lesions. METHOD: Several differential diagnoses were examined, including hidradenitis suppurativa, pilonidal cyst and pressure ulcers. It is important to be able to exclude these diagnoses based on the presentation, patient demographic and wound location. RESULTS: Biopsies verified the presence of RDD in the patient's suprasellar hypothalamic mass and skin lesions, confirming the patient had both CNS-RDD and cutaneous-RDD in the absence of lymphadenopathy. CONCLUSION: Recognising the unique manifestations of rare diseases such as RDD prevents delay of proper intervention and treatment.

Rosai-Dorfman disease manifesting as a solitary mass with fat in the thymus a case report.

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.