Search

Background: Intracranial Rosai–Dorfman disease (RDD) is a rare entity that usually comes as a surprise diagnosis after surgery. Despite accumulating case reports, the management strategy remains unclear. In this article, we describe our cases series and summarize the pertaining literature with emphasis on different management modalities. Methods: We conducted a retrospective review of all patients with intracranial Rosai–Dorfman disease operated at our department over a period of 13 years. Clinical, radiological, and surgical data of these patients were reviewed and summarized. We compared our data to those previously published in the literature about this rare disease. Results: All our cases were dural-based extrinsic lesions mimicking meningioma except one cerebellar lesion. Six out of seven cases underwent gross total resection (GTR) and one subtotal resection. Histopathology was confirmed in all cases using immune histochemistry. No patient received adjuvant radio or chemotherapy. There was no local recurrence in any case. One case had distant recurrence. Conclusions: Most intracranial RDD presentations are very similar to meningiomas either clinically or radiologically. The definite diagnosis is only confirmed through pathological examination. The rate of recurrence after GTR seems low either in our series or in the literature. There are currently insufficient data to support adjuvant treatment after surgical resection. In case of recurrence, the choice of effective therapeutic strategy is unclear. [ABSTRACT FROM AUTHOR]

Background: Monoclonal gammopathy of renal significance (MGRS) represents a range of disease processes arising from monoclonal proteins depositing in the kidney. These deposits vary and can be broadly grouped as containing a substructure or being non-organised. Their clinical phenotype can include proteinuria, haematuria, kidney injury and tubulopathies resulting in electrolyte changes. Case presentation: Crystal storing histiocytosis (CSH) is a rare form of MGRS that typically deposits in the interstitium but rarely in the glomerulus to cause progressive kidney disease. We report a case of a male with known monoclonal protein and progressive proteinuria, whose biopsy showed glomerular histiocytosis with non-crystallizing IgG kappa inclusions. Conclusion: This case reviews an unusual case of a glomerular histiocytosis with non-crystallizing IgG kappa inclusions. [ABSTRACT FROM AUTHOR]

An 8-year-old female presented to the oculoplastics clinic with 3 months of left upper eyelid fullness and edema. Examination showed a mass in the left anterior superior orbit with erythema. Imaging demonstrated a well-circumscribed superolateral orbital mass that was T1 hypointense and T2 hypo-to-iso intense with contrast enhancement. An incisional biopsy was performed via an upper lid crease incision. Histopathology showed aggregates of histiocytic cells with fibrosis and infiltration of eosinophils. Immunohistochemistry revealed positive CD68 and CD163 staining and negative langerin staining, confirming the diagnosis of indeterminate cell histiocytosis. There was no systemic involvement or associated dermatologic findings. Repeat exam 3 months later showed no change in the size of the lesion and the patient was referred to hematology-oncology for treatment. On most recent exam, the patient had no new symptoms or side effects following 3 months of oral hydroxyurea (25 mg/kg/day). Repeat orbital imaging showed no progression of the lesion and the patient will be monitored closely. Here, we report a rare case of isolated orbital indeterminate cell histiocytosis in a young child. [ABSTRACT FROM AUTHOR]

Historically, granulomatous inflammation has been described in association with tertiary syphilis. However, in recent years there have been increasing reports of granulomatous inflammation in patients with secondary syphilis. Here, we discuss two patients who presented with erythematous infiltrated papules and nodules and were eventually diagnosed with granulomatous secondary syphilis, with clearance of their rashes following treatment. We highlight important clues that can point clinicians and histopathologists toward a diagnosis of syphilis instead of differential diagnoses such as leprosy in reaction, cutaneous histiocytosis and lymphoma. Furthermore, after performing a literature review and from our own experiences, we wish to highlight that granulomatous syphilis is often palmoplantar-sparing and its presence may not necessarily be a feature of immunocompromised states, such as HIV infection. In this increasingly connected world, the recognition of an atypical presentation of an age-old disease in patients with different skin types must be underscored by close clinicopathological correlations. [ABSTRACT FROM AUTHOR]

The article "Indications and Techniques for Posterior Pituitary Biopsy" explores the use of posterior lobe sampling as a safer alternative to direct hypothalamic or infundibular biopsy. Through three case studies, the authors demonstrate successful histologic diagnosis of lesions in the hypothalamus and pituitary stalk without acute worsening of pituitary function. The procedure, performed via endoscopic endonasal transsphenoidal surgery, offers a lower risk of endocrine dysfunction compared to traditional methods, potentially aiding in the diagnosis of various pathologies. Further research is needed to validate these findings. [Extracted from the article]

Histiocytosis represents a group of uncommon disorders characterized by the abnormal accumulation of specialized immune cells, such as macrophages, dendritic cells, or monocyte-derived cells, in various tissues and organs. Over 100 distinct subtypes have been documented, each displaying a broad spectrum of clinical presentations and histological characteristics. Till today, histiocytosis has been addressed through a combination of chemotherapy, radiotherapy, and surgery, with varying responses from individual patients. Due to its atypical symptoms, it has been prone to misdiagnosis. Advances in our understanding of the cellular and molecular aspects of these conditions are paving the way for improved diagnostic methods and targeted therapies. Researchers have extensively investigated various mutations in patient samples. However, no paper has yet provided a comprehensive summary of the collective analysis of mutations and pathways. Hence, this paper consolidates research efforts that specifically concentrate on gene mutations identified in patient samples of different subtypes of histiocytosis. These insights are essential for developing targeted therapies and improving diagnosis. Further, it provides potential insights to enhance the development of more effective therapeutic approaches for rare diseases. Parts of the figure were drawn by using pictures from Servier Medical Art. Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License (https://creativecommons.org/licenses/by/3.0/). [ABSTRACT FROM AUTHOR]

Anaplastic lymphoma kinase (ALK)‐positive histiocytosis has emerged as a clinically relevant diagnosis featuring a wide span of clinical presentations, which are unified by the presence of ALK‐positive histiocytes on histopathology and molecular drivers involving the ALK kinase gene. This report presents an adult case of multisystem ALK‐positive histiocytosis with xanthogranuloma‐like features on histopathology that was responsive to ALK inhibition, and includes a review of ALK‐positive histiocytoses with cutaneous involvement reported in the literature. A 56‐year‐old male developed a widespread eruption of red‐brown papules on the face, trunk, and upper extremities. Histopathological evaluation revealed a well‐circumscribed, nodular dermal infiltrate of epithelioid histiocytes with Touton giant cells, rare bizarre multinucleated cells, and focal emperipolesis. The lesional cells were positive for CD68 and ALK1 immunohistochemical stains, and negative for CD1a. Next‐generation sequencing identified a DCTN1::ALK fusion. On imaging, he was found to have bone, lung, soft tissue, and salivary gland involvement. ALK inhibition was initiated with alectinib, resulting in rapid improvement of cutaneous lesions and eventual complete resolution of abnormal imaging findings, which was sustained at 24 months of follow‐up. This case adds to the spectrum of ALK‐positive histiocytoses and further demonstrates the positive response with targeted therapy. [ABSTRACT FROM AUTHOR]

Langerhans cell sarcoma (LCS), a rare malignant neoplasm in the general category of myeloid neoplasms characterized by overtly malignant Langerhans cells (LC) with conspicuous mitotic activity including atypical forms. Although most cases occur in adults, rare examples of LCS have been reported in children with variable clinical outcome. We present 2 childhood cases of Langerhans cell neoplasm with high grade sarcomatous features and OSBPL9::BRAF fusion and BRAF V600E mutation. [ABSTRACT FROM AUTHOR]

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 (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]