non-Langerhans Cell Histiocytosis Research Articles

Rosai-Dorfman-Destombes Disease in the Pediatric Head and Neck.

Rosai-Dorfman-Destombes disease (RDD), or sinus histiocytosis with massive lymphadenopathy, is a rare form of non-Langerhans cells histiocytosis. It has a wide-ranging variability in presentation since first described in 1969 but much of its characteristics in children remain unknown. A retrospective chart review of children diagnosed with RDD at a tertiary care children's hospital was conducted from 2000 to 2021. Twelve RDD patients were identified, with an average age of 7 years (SD 4.3). Males comprised 58% of the cohort, and African American ethnicity was most common (42%). Nodal RDD was found in 7 patients (58%). Nine patients (75%) presented RDD within the head and neck, 6 of whom had nodal RDD. The most common presentation was cervical lymphadenopathy, which most often involved levels V (67%), II (56%), III (44%), and I (11%), in order of frequency. Recurrence and persistence of disease after initial treatment was common, with 5 (42%) being disease free at the time of the last follow up. Fifty-eight percent (7/12) developed recurrence or had persistent disease and 4 required adjuvant systemic treatment with corticosteroids and/or chemotherapy. One patient succumbed after developing treatment related acute myelodysplastic leukemia (t-AML) from chemotherapy used to treat recurrent RDD. Pediatric RDD presents at a young age and most commonly involving cervical lymphadenopathy. Ongoing surveillance in the setting of persistence or recurrence without clearly defined prognostic risk factors is important.

Multicentric Reticulohistiocytosis Associated with an Early Form of Systemic Lupus Erythematosus: A Case Report of a Rare Disease, with Mini Review of the Literature.

Multicentric reticulohistiocytosis (MRH) is the most frequently described form of reticulohistiocytosis (RH), and it is classified as a class IIb non-Langerhans cell histiocytosis. It has been designated as multicentric, being characterized by multisystemic involvement. In fact, although mainly involving the skin, along with the joints, it is a systemic inflammatory condition potentially involving every internal organ. As MRH-related skin findings can mimic rheumatoid nodules or Gottron papules, the histopathology of the cutaneous lesions is often necessary for the correct diagnosis. Approximately one-third of MRH patients have confirmed concomitant autoimmune disorders. A wide variety of autoimmune disorders associated with the disease have been reported in the literature, suggesting immune dysfunction as a factor in the pathophysiology of MRH. A case of MRH associated with autoimmune manifestation is reported in the context of a mini review of the literature, with a focus on clinical presentation, treatments, and treatment outcomes. Moreover, eight cases of MRH associated with autoimmune diseases are briefly discussed.

PMON110 Panhypopituitarism as a Rare Presentation of Erdheim – Chester disease (ECD) in an Adolescent Patient

Abstract Background Erdheim-Chester disease (ECD) is a rare multisystemic histiocytic disorder. Only a dozen pediatric cases are reported. Here, we present a case of ECD in a pediatric patient who presented with short stature and delayed puberty. Clinical Case A 14-year-old male with history of autism and ADHD presented with short stature and pubertal delay. He grew along the 40th percentile until age 7 years when growth velocity declined. On exam, his height was 145.6 cm (0.98%ile, z-score -2.34), weight was 55.6 kg (63.19%ile, z-score 0.34), and testicular size was 5-6 mL. He had increased thirst and episodes of bedwetting since age 7. Bone age was delayed at 11 years 6 months. Further workup was recommended, but family was lost to follow up. At 16, he returned with continued poor growth, polydipsia, and nocturia. Height was 153 cm (0.26%ile, z-score -2.80), weight 61.1 kg (40%ile, z-score -0.25). Labs revealed IGF-BP3 2.8mcg/mL(3.1-8.9), IGF-1 35ng/mL(245-522), LH 1.2mIU/mL(0.29-4.77), and total testosterone <7.0 ng/dL(250-1100). Prolactin, cortisol, thyroid, and karyotype were normal. Growth hormone (GH) stimulation test confirmed GH deficiency. He was referred to oncology clinic when a brain MRI revealed a nodular enhancing suprasellar mass extending from the third ventricular floor to the dorsum sella along the pituitary stalk and rounded sclerotic lesion in the frontal bone. Biopsy of the suprasellar lesion was remarkable for foamy histiocytes positive for CD68, negative for S100 and CD1a, an eosinophilic cell background highlighted by S100 and synaptophysin, SALL4 negative. A diagnosis of xanthomatous hypophysitis was made. Additionally, lab studies confirmed diabetes insipidus (DI), treated with DDAVP. Growth hormone was trialed for 2 weeks, but he developed acute pancreatitis, so it was discontinued. He subsequently developed recurrent pancreatitis of unclear etiology requiring frequent hospitalization with development of insulin-dependent diabetes mellitus due to pancreatic damage. He was lost to follow up for 12 months after leaving home at age 18. He returned to our institution after incidental findings of 7th right rib expansile lytic bony lesions on abdominal CT during a pancreatitis admission. Biopsy of the rib lesion was positive for a BRAF-V600E mutation. Skeletal survey revealed new multiple small lytic skull lesions. Repeat brain MRI demonstrated new calvarial lesions, increased suprasellar mass. Chest CT scan showed a micronodular pattern with mediastinal lymph node enlargement. PET confirmed widespread multifocal FDG hypermetabolic lesions. Final diagnosis of ECD was made; he was started on targeted therapy with Vemurafenib, a BRAF inhibitor. Conclusion Erdheim-Chester disease (ECD) is a non-Langerhans cell histiocytosis, which rarely affects pediatric patients who present with bone pain and DI; however, here we present a case of ECD in an adolescent with short stature and multiple pituitary deficiencies to highlight the varied presentation of the disorder. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Clinical phenotypes and long-term outcome of kidney involvement in Erdheim-Chester histiocytosis

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis that frequently infiltrates the peri-kidney space ("hairy kidney" appearance), kidney pelvis and proximal ureters, leading to obstructive uropathy. Here, we analyzed the clinical characteristics, imaging findings and long-term kidney outcome of a large multicenter cohort comprising 195 consecutive patients with ECD. Retroperitoneal peri-kidney or peri-ureteral involvement was detected at diagnosis in 147 patients. Of them, 70 had hydronephrosis (bilateral in 47), and 16 with kidney atrophy (unilateral in 14). Kidney vascular peduncle infiltration was found in 60 patients, and kidney artery stenosis in 31. The estimated glomerular filtration rate (eGFR) at diagnosis was significantly lower in patients with than in those without peri-kidney involvement (median 74 vs. 98 mL/min/1.73 m2). Ureteral stenting often failed to achieve kidney function recovery. A total of 181 patients received medical therapies: first-line treatments included interferon-α (61%), BRAF-inhibitors (17%), mTOR-inhibitors (7%), or other drugs (15%). These therapies were efficacious for ECD but rarely induced kidney function improvement (one-year eGFR increase over 25% in under 10% of patients). After a median of 43 months, 19% of patients died and 5% developed kidney failure. Among patients with peri-kidney involvement, 44% developed chronic kidney disease (CKD) 3-5 at five years vs. 5% of those without. Unadjusted predictors of advanced CKD and kidney failure/death were age over 50 years, hypertension, BRAFV600E mutation, and baseline eGFR. At multivariable analysis, cardiovascular comorbidities were associated with advanced CKD, and age over 50 years with kidney failure/death. Thus, kidney involvement is common in ECD and can lead to CKD or kidney failure despite effective medical therapies or urological procedures.

Erdheim-Chester Disease with Isolated CNS Involvement: A Systematic Review of the Literature.

Erdheim–Chester disease (ECD) is a rare, sporadic, non-Langerhans cell histiocytosis that can have various presentations and higher mortality in patients presenting with neurological symptoms. We performed a systematic review to investigate and chronicle the frequency of neurological manifestations, imaging findings, treatments, and outcomes in published ECD patients presenting with neurological symptoms. A PubMed literature search was conducted for articles (published between January 1980 and June 2021) on ECD cases presenting with neurological manifestations. We analyzed the data of 40 patients, including our patient. Cranial neuropathies and ataxia were the most frequent clinical manifestations. A total of 50% of the symptomatic ECD CNS lesions were intraparenchymal and nearly 33% of patients died due to the disease itself or complications. CNS involvement may be the only manifestation of ECD and sometimes may require a repeat biopsy with IHC testing for excellent treatment outcomes.

Erdheim-Chester Disease with a Posterior Fossa Tumour Mimicking Neurosarcoidosis: a Case Report

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis described in 1930 by Jakob Erdheim and William Chester; it presents as a multisystemic entity that forms xanthogranulomas, foamy histiocytes surrounded by fibrotic tissue. Lesions are commonly located in long bones, central nervous system (CNS), cardiovascular system, lungs, kidneys, and skin. The CNS is involved in approximately 50% of cases and can compromise both extra- or intra-axial structures and therefore can mimic schwannomas or meningiomas, among other mass lesions [7, 4]. Clinical presentation will differ from patient to patient; thus, diagnosis depends greatly on imaging, immunohistochemistry, and genetic findings within the pathology analysis [8]. The pathogenesis of this disease remains unknown. It is most commonly found in the middle-aged male population [1, 2]. Here, we present a case of a middle-aged woman with an extra-axial lesion that was initially considered to be neurosarcoidosis proving the diagnostic challenge this entity implies.

485 The association between juvenile xanthogranulomas in neurofibromatosis type 1 patients and the development of leukemia: A systematic review

Importance: A subset of patients with neurofibromatosis type 1 (NF1) develop juvenile xanthogranulomas (JXGs), a non-Langerhans cell histiocytosis, and some of these patients also develop juvenile myelomonocytic leukemia (JMML). Yet, these associations are poorly delineated. Objective: Our objectives in this systematic review was to: (1) clarify the relationship between NF1, JXGs and JMML and identify patients that may benefit from additional screening, (2) describe the clinical characteristics of JXGs arising in NF1. Evidence Review: A literature search was performed within the PubMed database on July 7th, 2021. Articles were included if they were peer-reviewed human studies, in English, and discussed any association between NF1, JXG, and/or leukemia with individual patient data. Findings: Sixty-five articles met eligibility criteria, which included 181 individual patients. Fifty-six patients had NF1 and JXG without leukemia (Group 1), 98 patients had NF1 and leukemia (Group 2), 18 patients had NF1, JXG, and leukemia (Group3), and 9 patients had JXG and leukemia (Group 4). Among the 78 patients with NF1 and JXG, 23% (18/78) developed leukemia, and more specifically, 19% (15/78) developed JMML, which is higher than what has been reported in NF1 patients alone. Majority of patients with the triple association were male (93%, 14/15) and had a family history of NF1 (67%, 8/12). Conclusions: Our findings suggest that the NF1 patients with JXGs have an increased risk of developing JMML and leukemia, especially in males with a family history of NF1. Although the triple association remains rare, closer surveillance and screening of male patients with familial NF1 and JXGs lesions may be reasonable, particularly at early ages.

Pancreatic involvement in Erdheim-Chester disease: a case report and review of the literature

BackgroundErdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis characterized by infiltration of lipid-laden foamy macrophages within different tissues. Clinical manifestations of ECD are highly heterogeneous. Bone lesions are found in 80%-95% of patients, while extraosseous lesions usually involve the cardiovascular system, retroperitoneum, central nervous system (CNS), and skin. Pancreatic involvement in ECD has barely been reported.Case presentationA 29-year-old female initially presented with menoxenia, diabetes insipidus and diabetes mellitus. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) revealed hypermetabolic foci in the bilateral frontal lobe, saddle area, and pancreas. A 99mTc-MDP bone scrintigraphy scan revealed symmetrical increased uptake in distal femoral and proximal tibial metaphysis, which was confirmed to be osteosclerosis by high-resolution peripheral quantitative computed tomography. The patient underwent incomplete resection of the sellar mass. Histological examination of biopsies showed histiocytic aggregates, which were positive for S100 and negative for CD1a and CD207 on immunohistochemistry. Enhanced abdominal CT scan showed hypointense nodules within the body and tail of the pancreas. Endoscopic ultrasonography guided fine-needle aspiration (EUS-FNA) found no evidence of malignancy. She was diagnosed with ECD and treated with high-dose IFN-α. Repeated examinations at three-and eight-months post treatment revealed markedly reduction of both intracranial and pancreatic lesions.ConclusionsECD is a rare histiocytic neoplasm that can involve almost every organ, whereas pancreatic involvement has barely been reported to date. Here, we present the rare case of pancreatic lesions in ECD that responded well to interferon-α. We further reviewed reports of pancreatic involvement in histiocytic disorders and concluded the characteristics of such lesions to help diagnosis and treatment, in which these lesions mimicked pancreatic adenocarcinoma and caused unnecessary invasive surgeries.

Rare presentation of multiple thromboses in Erdheim–Chester disease: a case-based review

BackgroundECD is a rare non-Langerhans cell histiocytosis with diverse and heterogeneous clinical manifestations, ranging from single-lesion forms to multi-system involvement, including slowly progressing unifocal forms to rapidly evolving life-threatening disease.Case presentationA female patient presented with a 2-month history of fever. Imaging revealed multiple thromboses, bone destruction, an abnormal pituitary stalk, and clinical manifestations of diabetes insipidus. Excisional biopsy of a tibial lesion was sent for microscopic examination, and subsequent immunohistochemical testing was positive for expression of CD68 and CD163, and negative for expression of the immune markers CD1a, S100, and langerin. This confirmed the diagnosis of ECD. Treatment with methylprednisolone to inhibit the immune inflammatory response along with anti-cytokine therapy with an interleukin-6 antagonist resulted in satisfactory disease control.ConclusionWe report a rare case of multiple thromboses, embolism, and multiple organ involvement as the main presentation of ECD, suggesting that ECD should be considered in patients presenting with multiple thromboses associated with multisystem damage. We successfully treated our patient with glucocorticoids and interleukin-6 antagonist. This patient’s response to treatment suggests that hormone therapy and cytokine/chemokine therapy may be a potential novel treatment for patients with ECD without gene mutations.

What is the Role of Different Macrophage Subsets in the Evolution of Juvenile Xanthogranulomas?

There are several activated forms of macrophages: 2 main groups are designated M1 and M2. While M1 macrophages have proinflammatory, bactericidal, and phagocytic functions and are the dominant phenotype observed in the early stages of inflammation, M2 macrophages are involved in constructive processes such as tissue repair; they play a role in wound healing and are required for revascularization and re-epithelialization. Juvenile xanthogranuloma (JXG) is the most common non-Langerhans cell histiocytosis. Its pathogenesis is not well understood, but it is not considered a neoplastic entity. JXGs possibly appear as a reaction to a nonspecific injury such as trauma or viral infection, although a genetic predisposition has been suggested in some cases. Tissue damage leads to a histiocytic response. JXGs appear, evolve toward maturation, and then most of them spontaneously regress. Young JXGs are characterized by small macrophages scattered in the dermis, in apposition close to the epidermis. As the lesion matures, the number of foamy macrophages and Touton cells increases and other cell types such as plasma cells, lymphocytes, and polymorphs are observed. Regressing xanthogranulomas will show numerous spindle cells in Significant values are in bold.a storiform distribution, interstitial fibrosis, and few foamy and Touton cells. In this study, we studied the immunophenotypic profile of macrophages found in cutaneous JXGs according to their stage of maturation. We examined the skin biopsies from 25 patients; all were embedded in paraffin and stained with hematoxylin and eosin and for immunohistochemistry. Typically, all JXGs were positive for factor XIIIa and CD4, and were negative for CD1a. The following histiocyte markers were used: CD68, CD204, CD163, MAC387, and HAM56. Images were analyzed by Image J software; data were statistically evaluated by SAS 9.0 software. The cases showed a slight predominance of males and the preference of the JXGs for the axial skin. Lesions occupied the papillary and reticular dermis in 85% of the cases and extended to the subcutaneous fat in the remainder. Compared with mature and regressing JXGs, younger lesions had a higher density of M1 macrophages, stained with MAC387. This antibody labels the histiocytes that have recently arrived in the areas of inflammation. As the lesions matured, there was an overwhelming predominance of M2 macrophages. These cells tended to cluster against the epidermis, except in the 2 cases in phase of regression. This suggests that there is a cross-talk between the epidermis and macrophages and that receptors, cytokines, chemokines, and adhesion molecules may play a role in the development and evolution of JXGs. These results indicate that, for most of their life, JXGs are formed by repairing M2 macrophages and are not just an M1 macrophagic response to a local antigen. The process appears to be influenced by chemical-mediator epidermal-macrophage cross-talking, considering the tendency of these cells to accumulate against the dermoepidermal junction.

Paediatric Erdheim-Chester Disease in the Lateral Ventricle: A Case Report and Review of the Literature.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis caused by the expression of CD68-positive and CD1a-negative foam tissue cells, which is polar in pediatric patients. The study reports a case of an 8-year-old Chinese boy who presented with polydipsia and polyuria for 4 years, followed by central nervous system symptoms. Magnetic resonance imaging (MRI) showed a large lesion in the lateral ventricle. The histiocytes stained positively for CD68, CD163 and negatively for CD1a, glial fibrillary acidic protein (GFAP) and langerin, and were partially positive for S100 by immunohistochemical assay. More importantly, BRAFV600E staining was positive in tissue, and the BRAFV600E mutations was also detected by real-time quantitative PCR (RT-qPCR) in the intracranial lesion tissue. According to our review of the literature, this is a rare case of ECD in the ventricle, with a younger age.

An isolated intra-cranial rosai-dorfman disease radiologically mimicking the meningioma

Rosai-Dorfman disease is an uncommon benign non-Langerhans cell histiocytosis proliferative disorder. It commonly involves the lymph nodes and is classically presented with massive cervical lymphadenopathy. It can also involve the extra-nodal sites of the body and is reported in 43% of Rosai-Dorfman disease cases. The central nervous system is rarely involved in Rosai-Dorfman disease from which intra-cranial is more common than spinal lesions. An isolated dural-based intra-cranial Rosai-Dorfman disease is extremely rare. It usually mimics meningioma on radiological imaging. It is very difficult to diagnose the Rosai-Dorfman disease on imaging and intra-operative appearances of the lesion. We present a histopathologically proven case of an isolated Rosai-Dorfman disease involving the central nervous system in 49 years old female patient which was radiologically mimicking the meningioma.

Juvenile and adult xanthogranuloma: A 30-year single-center experience and review of the disorder and its relationship to other histiocytoses

BackgroundJuvenile xanthogranuloma (JXG) is the most common type of non-Langerhans cell histiocytosis whose cell of origin, etiology and pathogenesis are not fully understood. We aimed to provide an update on histopathologic and immunophenotypic profile of this well-characterized entity whose relationship to the other histiocytoses has received renewed attention in light of recent molecular genetic studies. Materials and methodsA retrospective review of all the cases with the pathologic diagnosis of “xanthogranuloma” was performed on our archives from 1989 to 2019. ResultsA total of 525 patients with 547 lesions diagnosed as JXG were identified with the median age of 4.5 years, a male predominance (M:F ratio 1.3:1) and a predilection for the head and neck region (40.8%). Cutaneous lesions comprised 76.8% cases and another 15.7% presented within soft tissues. The most common non-soft tissue, extracutaneous lesions included the brain (2.6%), and lungs (1.8%). Three basic histopathologic patterns were identified: early classic (EJXG) (14.2%), classic (CJXG) (45.3%), and transitional JXG (TJXG) (40.5%). Multinucleated giant cells, either Touton or non-Touton, were most frequently present in CJXG followed by TJXG. Mitosis was rare (<1/10 high-power field) among different patterns. There was an association among the patterns and lymphocytic infiltrates (P = 0.036), and presence of Touton or non-Touton giant cells (P < 0.001 for both) but not for mitotic count (P = 0.105) or eosinophilic infiltrates (P = 0.465). Additionally, there was a correlation between age groups and presence of non-Touton giant cells (P = 0.012) but not for Touton cells (P = 0.127). We have demonstrated that immunophenotypic expression of the lesion was not associated with age at diagnosis nor morphologic pattern: factor XIIIa 192/204 (94.1%), CD11c 75/77 (97.4%), CD4 82/84 (97.6%), CD68 200/201 (99.5%), CD163 15/15 (100%), CD1a 1/110 (0.9%), S-100 48/152 (31.6%), CD31 15/21 (71.4%), and vimentin 104/105 (99.0%). ConclusionWe have documented in a substantial series of cases of JXG that there is a correlation between one of the three basic histopathologic patterns with age at diagnosis, but with a consistent immunophenotype among the three patterns. Considering sensitivity and specificity rates, we suggest that a combination of CD11c, CD4, CD1a and either CD163 (preferred) or CD68 stains provides more specific diagnostic yield in the differentiation of JXG from other histiocytic disorders. JXG is also discussed in terms of its relationship and distinction from other similar histiocytic disorders in the context of MAPK/ERK pathway mutations.

Juvenile Xanthogranuloma: A Comparative Immunohistochemical Study of Factor XIIIa, CD11c, and CD4.

Juvenile xanthogranuloma is a group C and L non-Langerhans cell histiocytosis, and its cell of origin is still debatable. The expression of CD11c, a more recently described macrophage marker, and CD4 have not been studied comprehensively. This study aimed to expand immunophenotypic profile and hence our understanding of the origin of these lesions. The surgical pathology archive was searched for the cases with the pathologic diagnosis of "xanthogranuloma" from 1995 to 2019. Immunohistochemical (IHC) stains were performed for factor XIIIa, CD11c, and CD4. Morphologically, each lesion was classified into early classic, classic, or transitional subtypes. Seventy-seven cases were included with the median age of 7.8 years (male:female 1.3:1). Uniform positivity was noticed for CD4 (n = 77), CD68 (n = 37), CD163 (n = 5), and vimentin (n = 4) stains. Other stains included CD11c 75/77 (97.4%), factor XIIIa 71/76 (93.4%), S-100 protein 4/23 (17.4%), and CD1a 0/18 (0%). Despite insignificant association between morphologic subtype and main studied IHC stains, factor XIIIa reactivity was highest in transitional lesions and CD11c showed higher reactivity in early classic lesions. CD11c and CD4 are sensitive markers and showed promising results in the diagnosis of juvenile xanthogranuloma compared with factor XIIIa. Despite different reactivity of factor XIIIa and CD11c in various morphologic subtypes, such association was statistically insignificant.

A258 ROSAI-DORFMAN0-DESTOMBES DISEASE: A RARE CAUSE OF OBSTRUCTIVE JAUNDICE

BackgroundRosai-Dorfman-Destombes Disease (RDD) is rare histiocytic disorder that is most frequently seen in children and young adults. Gastrointestinal involvement is reported in <1% of cases and typically involves the small bowel and colon. Pancreatic and hepatic involvement has been previously reported but is extremely rare.AimsTo describe a case of obstructive jaundice in the setting of a very rare histiocytic disorder known as RDD.MethodsCase ReportResultsA 59-year old previously healthy male of Asian descent presented with obstructive jaundice. Initial imaging demonstrated intra and extrahepatic biliary duct dilation with concurrent diffuse enlargement of the pancreas compatible with autoimmune pancreatitis. Endoscopic retrograde cholangiopancreatography (ERCP) was performed with stenting and biopsy. ERCP demonstrated a distal common bile duct stricture with biopsies suggestive of low grade reactive changes and inflammation. Subsequent endoscopic ultrasound (EUS) guided biopsy of the pancreas showed active and chronic inflammation, necrosis, and atrophic pancreatic tissue, with no definitive evidence of autoimmune pancreatitis (Figure 1). Ca-19-9 and IgG4 were normal. He was treated with a course of prednisone and responded well, with repeat CT imaging showing almost complete resolution of the previously demonstrated pancreatic changes. A diagnosis of autoimmune pancreatitis was made. He re-presented 6-months later, however, with fatigue and repeat imaging now displayed lymphadenopathy in the neck, chest, and abdomen, and a bulky pancreatic head with associated hepatomegaly. Lymph node excisional biopsy confirmed the diagnosis of RDD with the presence of scattered histiocytic cells showing emperipolesis with a low number of IgG4 positive cells (Figure 1). The patient was promptly initiated on prednisone and rituximab and has since then had excellent clinical response.ConclusionsRDD is a rare non-Langerhans cell histiocytosis of unknown etiology that has a prevalence of 1:200 000. RDD clinically presents with painless bilateral cervical lymphadenopathy and can manifest with both nodal and extra nodal involvement. The most common sites of extra nodal disease are the skin and central nervous system, but rarely, can also present with pancreatic involvement. The use of fine needle guided biopsy in diagnosing RDD with extra nodal disease can be limited by low yield, sclerotic tissue, or non-diagnostic findings. For this reason, RDD with pancreatic involvement can masquerade as autoimmune pancreatitis, pancreatic malignancy and IgG4-related disease.This case report raises awareness about RDD with pancreatic and biliary involvement, a rare entity, that can present with obstructive jaundice. Figure 1: Histological sections of lymph node(left) with hystiocytic cells showing emperipolesis(arrow) and pancreas(right) showing active and chronic inflamation, necrosis and atrophyFunding AgenciesNone

Solitary juvenile xanthogranuloma of temporal bone: a case report

BackgroundJuvenile xanthogranuloma (JXG) is a kind of non-Langerhans cell histiocytosis, usually with skin lesions as the main manifestation. It rarely occurs in other tissues or organs and even more rarely is it found in the skull. Here, we report a case of xanthogranuloma derived from the temporal bone that was not present in any other parts of the body.Case presentationA 15-year-old boy had an unaccountable right migraine for 7 months. A mass with tenderness was located behind his right ear. The mass gradually increased in size, and his headache continued. Eventually, he came to our hospital for treatment. A computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed a cystic solid mass in the right temporo-occipital region with skull destruction. The clinical diagnosis was haemangiopericytoma and skull-derived tumour. Haematological and biochemical results were as follows: alanine aminotransferase (ALT) 7 U/L; aspartate aminotransferase (AST) 12 U/L; basophil percentage (BASO%) 1.2%; normal coagulation. The patient was successfully treated with total surgical resection of the tumour. Postoperative histopathology examination showed xanthogranuloma, and his prognosis after surgery was good.ConclusionsBecause JXG rarely occurs in the skull and lacks typical imaging findings, an accurate diagnosis is difficult. The diagnosis of this disease mainly depends on pathological examination and immunohistochemistry. If feasible, many intracranial lesions can be cured through complete resection.

Intermediate-dose cytarabine is an effective therapy for adults with non-Langerhans cell histiocytosis

BackgroundNon-Langerhans cell histiocytosis, including Erdheim–Chester disease (ECD), Rosai–Dorfman disease (RDD), indeterminate cell histiocytosis (ICH), and unclassified histiocytosis, is a rare disorder lacking a standard treatment strategy. We report our experience using intermediate-dose cytarabine as the first or subsequent therapy in non-Langerhans cell histiocytosis.ResultsNine ECD patients, 5 RDD patients, 1 ICH patient and 1 unclassified histiocytosis patient were enrolled. Intermediate-dose cytarabine therapy was administered as 0.5–1.0 g/m2 of intravenous cytarabine every 12 h for 3 days every 5 weeks. The median age at cytarabine initiation was 47.5 years (range 18–70 years). The median number of cycles of cytarabine administered was 5.5 (range 2–6). The overall response rate (ORR) was 87.5% in the overall cohort, including 12.5% with complete response and 75.0% with partial response. One patient experienced disease recurrence 19 months after cytarabine therapy. The median follow-up duration for the entire cohort was 15.5 months (range 6–68 months). The estimated 2-year progression-free survival and overall survival rates were 85.6% and 92.3%, respectively. The most common toxicity was haematological adverse events, including grade 4 neutropenia and grade 3–4 thrombocytopenia. No treatment-related deaths occurred.ConclusionsIntermediate-dose cytarabine is an efficient treatment option for non-Langerhans cell histiocytosis patients, especially for those with CNS involvement.

Multiple Drug Regimen-Refractory Rosai-Dorfman-Destombes Disease Mimicking Relapsing Polychondritis Successfully Treated with Cobimetinib.

Rosai–Dorfman–Destombes disease (RDD) or sinus histiocytosis with massive lymphadenopathy is a rare non-Langerhans cell histiocytosis of unknown cause. The disease often manifests as painless bilateral cervical lymphadenopathy associated with systemic symptoms such as fever and weight loss. Extranodal disease is also frequent and can involve any organ, mostly the skin, nasal cavity, bone, and retro-orbital tissue. Swelling of cartilaginous tissues, such as the helix of the ear or laryngeal structures, may mimic the entity known as relapsing polychondritis. Although spontaneous remission is the most expected evolution, some cases require systemic treatment with prednisone, methotrexate or cytotoxic agents, with variable rates of success. In this respect, since somatic variants in the genes involved in the mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK) pathway have been observed to play a pathogenic role in RDD. Therefore, the use of therapies targeting these pathogenic variants appears to be a reasonable strategy. Here we present the case of a 37-year-old woman with RDD and extensive extranodal involvement that showed a rapid and complete response to the MEK inhibitor cobimetinib.LEARNING POINTSRosai–Dorfman–Destombes disease (RDD) may mimic the entity known as relapsing polychondritis but should be treated with drug therapy for the underlying disease.Mutations in MAPK/ERK pathway components should be determined in RDD with systemic involvement, although testing to determine every somatic mutation responsible for the disease is not available in all healthcare centres.MEK inhibitors like cobimetinib could be effective in RDD cases with severe and refractory systemic disease, even if molecular analysis has not been possible.

A Case of Erdheim-Chester Disease with Omental Caking Initially Mistaken for a Malignancy

Introduction: Erdheim-Chester disease (ECD) is an uncommon non-Langerhans cell histiocytosis. Bilateral symmetric sclerosis of the long bones and possible multiorgan involvement are the main presentations of this disease. Histologically, lipid-laden foamy histiocytes are positive immunochemically for CD68 (occasionally for PS100) and negative for S100 and CD1a in ECD. Case Presentation: We describe the case of a 35-year-old man diagnosed with ECD with peritoneal and retroperitoneal infiltrations and bone involvement. The diagnosis of ECD was only confirmed after two years of non-specific abdominal pain, nausea, and weight loss. Primarily, the patient’s clinical symptoms and abdominal computed tomography (CT) findings, which indicated omental caking, peritoneal thickening, and perinephric soft tissue density, suggested an intra-abdominal malignancy. Finally, a peritoneal biopsy was carried out, which demonstrated xanthogranulomatous infiltrations from ECD. Further radiographic skeletal survey based on histopathological results showed symmetric osteosclerosis of the long bones. Conclusion: Although ECD, associated with peritoneal and retroperitoneal infiltrations, is an uncommon finding, it should be included in the differential diagnosis of patients with non-specific gastrointestinal manifestations, along with multiorgan involvement and typical radiological findings.

Disseminated Juvenile Xanthogranuloma: A Case Report

Introduction: Histiocytoses are localized or systemic diseases that can broadly be classified into Langerhans cell histiocytosis and non-Langerhans cell histiocytosis. Juvenile Xanthogranuloma (JXG) belongs to the latter group, which occurs in around 0.5% population younger than 5 years, and presents as solitary or multiple lesions. Here, we present a case of disseminated JXG in an infant with the lesions regressing spontaneously. Case presentation: A 7-month-old boy presented with multiple erythematous nodular lesions over the body excluding limbs for 3 months. Initial laboratory work up was normal. Skin histopathology showed a dermal nodule with sheets of histiocytes exhibiting grooved vesicular nuclei and pale eosinophilic cytoplasm along with touton giant cells. Immunohistochemistry markers further confirmed the diagnosis. Lesions healed completely with symptomatic relief in 1.5 years and no recurrence occurred. Discussion: Disseminated JXG is a benign childhood disorder that can sometimes be associated with internal organs involvement mainly bones, eyes, and brain. Serious complications may follow in case of extracutaneous spread. Most frequently, JXG follows the occurrence of another neoplastic disorder but can sometimes appear de novo. Skin biopsy is required for the diagnosis and better education of the family. Conclusion: JXG in infancy is a rarity in South Asia. Therefore, along with the clinical judgment, clinicians must also get histological confirmation in order to manage this disorder successfully. Close surveillance for multiorgan involvement is also required to avoid any irreversible sequalae.