Langerhans cell histiocytosis: lack of a viral etiology

BRAFV600E-induced senescence drives Langerhans cell histiocytosis pathophysiology

Langerhans cell histiocytosis (LCH) is a potentially fatal condition characterized by granulomatous lesions with characteristic clonal mononuclear phagocytes (MNPs) harboring activating somatic mutations in mitogen-activated protein kinase (MAPK) pathway genes, most notably BRAFV600E. We recently discovered that the BRAFV600E mutation can also affect multipotent hematopoietic progenitor cells (HPCs) in multisystem LCH disease. How the BRAFV600E mutation in HPCs leads to LCH is not known. Here we show that enforced expression of the BRAFV600E mutation in early mouse and human multipotent HPCs induced a senescence program that led to HPC growth arrest, apoptosis resistance and a senescence-associated secretory phenotype (SASP). SASP, in turn, promoted HPC skewing toward the MNP lineage, leading to the accumulation of senescent MNPs in tissue and the formation of LCH lesions. Accordingly, elimination of senescent cells using INK-ATTAC transgenic mice, as well as pharmacologic blockade of SASP, improved LCH disease in mice. These results identify senescent cells as a new target for the treatment of LCH.

Clinicopathological and Immunohistochemical Study of Head and Neck Langerhans Cell Histiocytosis from Latin America

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplastic proliferation with variable clinical behavior caused by the accumulation of CD1a⁺/CD207⁺ histiocytes, associated with a variable number of eosinophils, lymphocytes, plasma cells and multinucleated giant cells, most commonly observed in male children. LCH is uncommon in the head and neck region, occurring as ulcerated and reddened plaques or nodules that cause destruction of adjacent soft tissues and bone. The exact etiology of LCH is still unknown and controversial, with possible etiologic role of viruses, including Epstein-Barr virus (EBV). The aim of this study was to describe the clinicopathologic and immunohistochemical features of patients with LCH of the head and neck region. Clinical data from 19 patients with LCH were obtained from the archives of the Federal University of Rio de Janeiro and the Clinical Head and Neck Center of Guatemala. All cases were submitted to morphological, immunohistochemical analysis with CD1a, CD207, CD3, CD20, CD68, S-100 and Ki-67 and in situ hybridization for EBV. Ten cases were female and 9 male, with mean age of 11.5 years. Fourteen cases were located in the oral cavity, three cases in lymph nodes, and two cases in the scalp. In regard to the oral lesions, 13 cases were intra-osseous with six cases in anterior mandible, five cases in posterior mandible, and two cases in posterior maxilla while one case was located exclusively in the gingiva. The inflammatory pattern showed variation in the number of plasma cells, eosinophils and lymphocytes, while tumor cells were positive for CD1a, S-100 and CD68 in all cases, and positive for CD207 in 18 cases. In situ hybridization for EBV were negative in all cases.

Cytomegalovirus and Langerhans Cell Histiocytosis: Is There a Link?

Background:

Langerhans cell histiocytosis is a rare proliferative histiocytic disease of unknown etiology. Histologically, it is characterized by granuloma-like proliferation of Langerhans-type dendritic cells derived from bone marrow. Many investigators have suggested the possible role of viruses such as Epstein-Barr virus, human herpesvirus-6 (HHV-6), herpes simplex virus (HSV) types 1 and 2, and Cytomegalovirus in the pathogenesis of Langerhans cell histiocytosis.

Objectives:

In this study, we have investigated the presence of Cytomegalovirus in Langerhans cell histiocytosis in Iranian children.

Patients and Methods:

In this retrospective study, we have investigated the presence of Cytomegalovirus DNA expression, using paraffin-embedded tissue samples of 30 patients with Langerhans cell histiocytosis and 30 age and site-matched controls by qualitative Polymerase Chain Reaction (PCR) method.

Results:

No significant difference in prevalence of Cytomegalovirus presence between patients and controls was found. Cytomegalovirus was found by qualitative PCR in only 2 (6.66%) out of 30 patients and in 1 (3.3%) of 30 control samples with a P value of 1 (1.00 > 0.05) using chi-square test with OR: 2.07; 95% CI of OR: 0.18 - 24.15.

Conclusions:

Our findings do not support the hypothesis of a possible role for Cytomegalovirus in the pathogenesis of Langerhans cell histiocytosis.

Detection of Epstein-Barr Virus DNA in Langerhans Cell Histiocytosis

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare histiocytic proliferation of unknown etiology. It is characterized by granuloma-like proliferation of Langerhans-type dendritic cells and mainly affects young children. Although multiple investigators have suggested the possible role of viruses, such as Epstein-Barr virus (EBV), human herpesvirus-6 (HHV-6), Herpes simplex virus (HSV) types 1 and 2, and Cytomegalovirus (CMV) in the pathogenesis of LCH, it remains, however, debated.

OBJECTIVES

The EBV infection is reported to be associated with LCH. Nevertheless, no report could be found about involved Iranian children in English medical literature. In this study, we investigated the presence of EBV in Iranian children with LCH.

PATIENTS AND METHODS

In this retrospective study, in which we investigated the prevalence of presence of EBV DNA in LCH, using paraffin-embedded tissue samples of 30 patients with LCH and 30 age and tissue-matched controls, who were operated for reasons other than infectious diseases (between the years 2002 and 2012), by real-time polymerase chain reaction (RT-PCR) method, in the department of pediatric pathology. No ethical issues arose in the study, because only the pathology reports were reviewed, retrospectively, and the patients were anonymous.

RESULTS

There was a significant difference in prevalence of EBV presence between patients and controls. The EBV was found by RT-PCR in 19 (63.33%) out of 30 patients and only in eight (26.7%) of 30 control samples. The P = 0.004, was calculated using chi-square test (OR: 4.75; 95% CI: 1.58 ‒ 14.25).

CONCLUSIONS

Our study is the first investigation performed on patients with LCH and its possible association with EBV in Iran. Considering the P = 0.004, which is statistically significant, the findings do support the hypothesis of a possible role for EBV in the pathogenesis of LCH. These results are in accordance with several previous investigations, with positive findings.

Langerhans cell histiocytosis in a pediatric HIV patient

Children infected with human immunodeficiency virus (HIV) have an increased risk of malignancies. Herein, we present a 16 month old HIV infected child receiving antiretroviral therapy who presented with pain and swelling of both knees and ankles. This child was diagnosed as Langerhans cell histiocytosis (LCH) which is an uncommon proliferative disorder rarely reported in a HIV patient. The child was treated with chemotherapy and is well clinically. Infiltrative disorders like LCH should be kept among the differential diagnosis of bony pain and swelling in HIV infected children.

Vulvar Langerhans cell histiocytosis: a case report

Langerhans cell histiocytoses (LCH) are a rare group of disorders that comprise a large spectrum of diseases initially known as histiocytosis X. In this case report, we relate a case of LCH affecting the vulva of a 47-year-old female. The patient presented since 3 years with a vulvar lesion characterized by non-healing ulcers and a perineal granuloma on which she underwent surgery. Professionals should keep in mind not to treat straightforwardly lesions of the genital tract as simple sexually transmitted diseases. Chronic, atypical genital lesions seen in women need to be worked up and dealt with accordingly.

Role of fine needle aspiration in the diagnosis of the rare disease of langerhans cell histiocytosis in a child

Langerhan's cell histiocytosis (LCH) results from the proliferation of immunophenotypically and functionally immature, morphologically rounded Langerhan's cells along with eosinophils, macrophages, lymphocytes, and, commonly, multinucleated giant cells. Here we report a case in a 6-year-old boy of differential diagnoses including dermatopathic lymphadenitis (DL), parasitic infection, Kimura's disease, hypersensitivity reactions, cat-scratch disease, sinus histiocytosis with massive lymphadenopathy (SHML), hyperplasic lymph nodes, and lymphoma.

A 6-month-old boy with persistent pruritic eruption. Langerhans cell histiocytosis

A previously healthy 6-month-old boy presented to the pediatric dermatology clinic for evaluation of a persistent, pruritic eruption. This eruption involved the scalp, extremities, and inguinal creases and was intensely pruritic. The patient had been previously treated with multiple topical corticosteroids and antifungals, all with minimal improvement. He born at full term and was otherwise well and thriving. Review of systems was negative. Examination revealed erythematous to yellow scaly, greasy plaques, some with underlying purpuric papules in the frontal, temporal, and vertex of the scalp, post-auricular regions, and the conchae of both ears. There were also scattered papules and purpura noted in the inguinal creases, and hyperkeratotic yellow papules on the extensor extremities. He had no abnormal lymphadenopathy or hepatosplenomegaly. The remainder of his examination was normal. A diagnostic skin biopsy was performed.

Langerhans Cell Histiocytosis: a Case Report

Langerhans cell histiocytosis is a disease which results from accumulation or proliferation of a clonal population of cells with the phenotype of Langerhans cells arrested at an early stage of activation that are functionally deficient. The etiology and pathogenesis of the disorder are still unknown. There are ongoing investigations to determine whether it is a reactive or a neoplastic disease. The fact is that neoplastic and reactive processes may have many clinical and pathological similarities. Some emphasize the role of “cytokine storm” in Langerhans cells. Further studies are necessary in all areas, from the etiology and pathogenesis to diagnosis and therapy. Langerhans cell histiocytosis primarily affects bones, but less commonly it may involve other organ systems, or present as a multisystem disease. The clinical course is variable, from benign forms with spontaneous resolution, to chronic disseminated forms with fatal outcome. This is a report of a 29-year-old man with Langerhans cell histiocytosis with an onset at the age of 8, which later progressed to a multisystem disease. Apart from lesions on the skin and exposed mucous membranes, the patient also presented with: diabetes insipidus, granuloma of the right femur and slight bulbar protrusion of the right eye. The patient experienced spontaneous pneumothorax on two occasions. The diagnosis of Langerhans cell histiocytosis was histologically confirmed using electron microscopy by presence of Birbeck granules in the histiocytes. A favorable therapeutic response was obtained after systemic corticosteroid therapy.

An exploratory epidemiological study of Langerhans cell histiocytosis

We explored potential risk factors associated with Langerhans cell histiocytosis (LCH) in a predominantly Hispanic population in Los Angeles. Sixty children with LCH (cases) and, 150 randomly selected patients (controls) were interviewed. There was no statistically significant difference between cases and controls in the following: Family history of thyroid disease, smokers in the family, maternal problems during pregnancy, and pesticide exposure. Cases were more likely to report a family history of cancer (OR 2.5), infection during infancy (OR 2.76), and parental occupational exposure to metal, granites, or wood dust (OR 2.48).

Smoking-related interstitial lung diseases

Cigarette smoke, a toxic collection of thousands of chemicals generated from combustion of tobacco, is recognized as the primary causative agent of certain diffuse interstitial and bronchiolar lung diseases. Most patients afflicted with these disorders are cigarette smokers, and smoking cessation has been shown to be capable of inducing disease remission and should occupy a pivotal role in the management of all smokers with these diffuse lung diseases. The role of pharmacotherapy with corticosteroids or other immunomodulating agents is not well established but may be considered in patients with progressive forms of smoking-related interstitial lung diseases.

Langerhans cell histiocytosis: Current concepts and treatments

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder of cells with the phenotype of activated Langerhans cells. The diagnosis of LCH is often delayed or missed. Many questions about LCH remain to be answered, including whether it is caused by a malignancy or by immune dysregulation. Data from the early 1990s showed that LCH consisted of an accumulation of monoclonal LCH cells, suggesting a neoplastic disorder. However, further investigations with current sophisticated techniques have not shown consistent genomic aberrations. Recent data which suggests a role for an IL-17A dependant pathway of dendritic cell fusion in LCH remains to be proven. The most recent data taken together swing the pendulum towards an immunologic aberration. The clinical course of LCH is highly variable, ranging from a self-healing solitary bone lesion to widely disseminated life-threatening disease. Patients with multisystem (MS) disease with organ dysfunction, particularly those refractory to front line therapy, and those with multiple reactivations of disease associated with significant permanent sequelae represent the greatest challenge. Early switch of refractory patients to salvage therapies has contributed to the improvement in survival of MS-LCH patients. Due to the rarity of LCH in children and adults, patients must be enrolled on multi-national clinical trials, whenever possible, to advance our knowledge of the optimal therapeutic strategies and long-term outcomes.

Histiocytosis disorders in Northeast Egypt: epidemiology and survival studies (a 5-year study)

Histiocytosis disorders include a wide group of disorders characterized by monocytes, macrophages and dendritic cell infiltration of different tissues. There are few clinico-epidemiologic studies of such disease. Our study was designed to look at the clinico-epidemiological features and outcome of patients with histiocytosis disorders in Northeast Egypt. Twenty-seven cases with histiocytosis disorders accrued over a 5-year period were analyzed and classified as having unifocal, multifocal, or multisystem disease. They were 14 males and 13 females. Twenty-two patients representing 81.5% of cases were more than two years of age while 5 patients (18.5%) were less than 2 years. Lymphadenopathy was the commonest presentation (55.55%) followed by bone lesions (44.44%). Involvement was unifocal in 12, multifocal in 10, and multisystem in 5 cases. The histological features were relatively uniform regardless of the clinical severity, and consisted of Langerhans cells, eosinophils, histiocytes, plasma cells, giant cells and fibrosis. The treatment consisted of a combination of surgery, chemotherapy, and/or radiotherapy. Lymphadenopathy was the most common clinical presentation in our locality. Response to treatment was poor in patients with multisystem disease. Patients with age less than 2 years were more likely to have increased risk of morbidity and mortality, due to widespread disease.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a poorly understood proliferative disease, with different patterns of clinical presentation. Currently it is classified according to the number and type of system involved and the degree of organ dysfunction. The aetiology of the disease remains uncertain, and in some cases the disease is polyclonal, suggesting a reactive condition. Many cytokines have been implicated in the pathogenesis of LCH. Different therapeutic approaches can be considered depending on the affected organ, including surgery, radiotherapy and chemotherapy. Long-term organ dysfunction may remain, despite disease control and/or eradication, making indefinite supportive treatment mandatory. Here we present a literature review on all of the aspects of the disease, treatment approaches and existing protocols, and finally an adult clinical case.

Herpes-virus infection in patients with Langerhans cell histiocytosis: a case-controlled sero-epidemiological study, and in situ analysis

Background

Langerhans cell histiocytosis (LCH) is a rare disease that affects mainly young children, and which features granulomas containing Langerhans-type dendritic cells. The role of several human herpesviruses (HHV) in the pathogenesis of LCH was suggested by numerous reports but remains debated. Epstein-barr virus (EBV, HHV-4), & Cytomegalovirus (CMV, HHV-5) can infect Langerhans cells, and EBV, CMV and HHV-6 have been proposed to be associated with LCH based on the detection of these viruses in clinical samples.

Methodology

We have investigated the prevalence of EBV, CMV and HHV-6 infection, the characters of antibody response and the plasma viral load in a cohort of 83 patients and 236 age-matched controls, and the presence and cellular localization of the viruses in LCH tissue samples from 19 patients.

Principal Findings

The results show that prevalence, serological titers, and viral load for EBV, CMV and HHV-6 did not differ between patients and controls. EBV was found by PCR in tumoral sample from 3/19 patients, however, EBV small RNAs EBERs –when positive-, were detected by in situ double staining in bystander B CD20⁺ CD79a⁺ lymphocytes and not in CD1a⁺ LC. HHV-6 genome was detected in the biopsies of 5/19 patients with low copy number and viral Ag could not be detected in biopsies. CMV was not detected by PCR in this series.

Conclusions/Significance

Therefore, our findings do not support the hypothesis of a role of EBV, CMV, or HHV-6 in the pathogenesis of LCH, and indicate that the frequent detection of Epstein-barr virus (EBV) in Langerhans cell histiocytosis is accounted for by the infection of bystander B lymphocytes in LCH granuloma. The latter observation can be attributed to the immunosuppressive micro environment found in LCH granuloma.

Incidence of Langerhans cell histiocytosis in children: a population-based study

BACKGROUND

Langerhans cell histiocytosis is a rare disease of unknown etiology. We wanted to assess the population-based incidence of LCH in a well-defined cohort of children.

METHODS

We identified all children <15-years old treated with LCH during the 10 years period 1992-2001 at the Department of Pediatrics, Karolinska University Hospital in Stockholm, the referral center for children with LCH in Stockholm County. We also contacted the Departments of Dermatology, Orthopedics, and Neurosurgery for possible additional patients.

RESULTS

Twenty-nine children (16 males) with LCH were identified, with a median age at diagnosis of 3.8 years (2 months-13.7 years). All children but one had a definitive diagnosis of LCH. The minimum incidence of LCH is estimated to 8.9/10(6) children per year. At diagnosis, 20 children (69%) had single system (SS) and 9 (31%) multisystem (MS) manifestations. Five of the 20 children with SS eventually developed MS disease, thus 14 (48%) had MS involvement at the maximal extent of disease (4.3/10(6) children per year). Interestingly, 22 children (76%) were diagnosed during the fall (September-November, n = 12) and winter (December-February, n = 10) seasons, as compared to seven children during the spring (March-May = 1) and summer (June-August = 6) seasons (P = 0.005, Chi-square).

CONCLUSIONS

The incidence of childhood LCH in our study is higher than previously reported. In our patient cohort, LCH was more commonly diagnosed during the fall and winter season as compared to the spring and summer season. Whether this seasonal variation can be confirmed in larger studies and whether it has relevance for LCH pathophysiology remains to be elucidated.

Langerhans cell histiocytosis of the thyroid gland

OBJECTIVES

A case is reported in which Langerhans cell histiocytosis was found in the thyroid gland. Although the thyroid gland is frequently affected with multiple common diseases, a search of the English language literature suggests that Langerhans cell histiocytosis in the thyroid gland is rarely reported.

STUDY DESIGN

The study design was of a case report and literature review.

SETTING

Academic tertiary referral practice.

METHODS

A case was reported, and the literature was reviewed.

RESULTS

A 31-year-old woman presented with an enlarged, diffusely firm, nontender, nonmobile, and not particularly nodular thyroid gland with mild compressive symptoms. She had intermittent skin papules and 1 episode of gingival ulceration. Ultrasound showed diffusely, hypoechoic thyroid with dimensions of 36 x 20 x 16 mm on the right and 36 x 16 x 17 mm on the left. No distinct nodules were noted, and thyroid function test results were normal. Laboratory testing for autoimmune abnormalities of the thyroid was negative for antithyroid peroxidase, antiparietal cell, and anti-smooth muscle cell antibodies. She tested positive for serum antithyroglobulin antibodies. A computed tomographic scan demonstrated abnormal low attenuation of her thyroid gland without any distinct nodules or masses. A fine-needle aspiration and core biopsy confirmed the diagnosis of Langerhans cell histocytosis. Dissection was technically challenging because of the firm and nonmobile lobes. Densely adherent strap musculature was encountered bilaterally, and the rare presence of a nonrecurrent laryngeal nerve was noted on the right. Histologically, thyroid parenchyma was largely obliterated by a diffuse infiltrate of mononuclear spindled to epithelioid histiocytes with few residual thyroid follicles. These histiocytes had moderate to abundant pale to eosinophilic cytoplasm, and some had prominent nuclear grooves and indentation/clefts, consistent with Langerhans histiocytes. Plasma cells and lymphocytes were sparsely dispersed. Immunohistochemistry showed that these histiocytes were positive for S-100, and rare lesional histiocytes were also positive for CD1a. Eosinophils were not readily identified in this lesion.

CONCLUSIONS

Langerhans cell histiocytosis in the thyroid gland is a rarely reported disease, with controversy over its management. This disease should be considered in the differential diagnosis of a diffusely irregular and firm thyroid gland, and multidisciplinary team cooperation is important for its diagnosis and management.

Development of Langerhans cell histiocytosis associated with chronic active Epstein-Barr virus infection

Chronic active Epstein-Barr virus (CAEBV) infection is characterized by a status of lymphoproliferative disease of EBV-infected cells, resulting in chronic or recurrent infectious mononucleosis-like symptoms. CAEBV is always accompanied by life-threatening complications. We report the case of a 2-year-old female patient with CAEBV who subsequently developed Langerhans cell histiocytosis (LCH) presenting with bilateral exophthalmos, bone, and skin involvement. In situ hybridization for EBER revealed EBV-infected B-cells present in lesional tissue implying that interactions between EBV-infected B-cells and lesional Langerhans cells may be associated with the development of LCH.

EBV+ lymphoproliferative disease following prolonged chemotherapy for refractory LCH

Epstein-Barr virus (EBV) is a herpesvirus for which latent infection in B lymphocytes occurs in most individuals by middle childhood. Clinically significant reactivation of this virus occurs in the context of suppressed cell-mediated immunity, occasionally developing into lymphoproliferative disease (EBV-LPD). EBV reactivation is rarely associated with intensive chemotherapy alone. Here we present the case of a 4-year-old female who developed EBV-LPD as a complication of prolonged immunosuppressive chemotherapy for her multiply-recurrent Langerhans cell histiocytosis (LCH).

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a complex disease entity comprised of three distinct clinical syndromes that demonstrate indistinguishable histology. These syndromes are: eosinophilic granuloma, which is predominantly osseous or pulmonary; Hand-Schûller-Christian's disease, which involves multiple organ systems and, most typically, the skull base; and Letterer-Siwe's disease, the most severe disease manifestation, which typically involves the abdominal viscera. This article reviews our current understanding of Langerhans cell histiocytosis by discussing the history, histology, etiology, and treatment of the disease. It focuses on the radiographic findings and imaging modalities that are the most useful in disease diagnosis and management.

Drug therapy for the treatment of Langerhans cell histiocytosis

Langerhans cell histiocytosis results from the abnormal accumulation of a class of dendritic cells normally found in the skin, which proliferate in many organ systems along with lymphocytes, macrophages and eosinophils. Standard therapy for Langerhans cell histiocytosis includes vinblastine and prednisone with or without methotrexate and mercaptopurine, depending on the extent of disease. Effective therapies for patients unresponsive to the above include cytosine arabinoside and cladribine. Thalidomide has proven useful for patients with Langerhans cell histiocytosis of the skin and/or bone. Emerging therapies include the use of monoclonal antibodies against the CD1a or CD52 epitopes found on Langerhans cells. Specific therapies directed against the cytokines that are apparently critical to the abnormal proliferation have not yet been defined.

Langerhans cell histiocytosis and human herpes virus 6 (HHV-6), an analysis by real-time polymerase chain reaction

Patients with Langerhans cell histiocytosis (LCH) usually present to orthopedic surgeons because this disease most commonly affects bone. The pathogenesis of LCH is unknown, although roles for environmental, infectious, immunologic, and genetic causes have been postulated. More specifically, there is limited data suggesting that human herpes virus 6 (HHV-6) may be a potential etiologic agent. Frozen biopsy material was obtained from 13 patients with LCH and 20 patients without the disease. After ensuring histologic adequacy of the material, the tissue was tested for HHV-6 by qualitative and quantitative real-time TaqMan PCR. Four of 13 patients with LCH had evidence of HHV-6 DNA in their tissue while 7 of 20 control patients tested positive for HHV-6 genome. Viral loads are reported for the positive patients; no statistical difference was observed in the presence or quantity of HHV-6 DNA found in either population, suggesting that the prevalence of HHV-6 in the tissue of LCH patients is the same as that found in tissue from individuals without disease.

Langerhans cell histiocytosis: current insights in a molecular age with emphasis on clinical oral and maxillofacial pathology practice

Langerhans cell histiocytosis (LCH) commonly involves the oral and maxillofacial region, and comes to the attention of dental practitioners when a patient presents with orofacial pain and a bony or soft tissue lesion. This is a relatively rare entity, which has made it difficult to investigate the clinical, biologic, and molecular aspects of the disease. Treatment protocols are not well defined, particularly in adults. During the past decade, the Histiocyte Society has formulated various LCH categories, based on risk stratification, and treatment protocols for the pediatric population. Adult trials are currently available through the Histiocyte Society. Although there has been considerable controversy, the neoplastic nature of LCH has been established by demonstrating clonality. LCH symptoms and the development and persistence of LCH lesions have been ascribed to a "chemokine/cytokine storm" due to autocrine and paracrine mechanisms. Discovery of biologic, cytogenetic, and molecular abnormalities in LCH have already affected treatment by providing novel therapeutic targets.

Histiocytosis and bone: experience from one major Sydney teaching hospital

Langerhans cell histiocytosis (LCH) has diverse presentations which can bring it before all physicians regardless of specialty. A retrospective audit was undertaken at Westmead Hospital, Sydney, Australia, to ascertain the incidence, epidemiology and clinical features of patients with LCH over a 10-year period (1994-2004). A total of 12 patients was identified (six male, six female). Eleven patients had involvement of the skeletal system, three of the patients had pulmonary LCH and only one patient presented with soft tissue involvement (nose and antrum). Three patients had diabetes insipidus. Our results are consistent with that noted in the published literature and confirm the low incidence, diverse nature of presentation and the differing treatment strategies available for this rare and yet interesting condition.

The Nikolas Symposia and histiocytosis

Histiocytoses are a group of rare diseases that involve histiocytes (literally tissue cells (Greek), but in reality tissue-resident macrophages and dendritic cells), which are derived from bone-marrow stem cells. Histiocytoses pose problems similar to those of other rare diseases of childhood. Individual physicians see few cases, disease material is hard to collect and families suffer from lack of information and understanding. In this article, we describe how a series of 'think tank' meetings, the Nikolas Symposia, which have concentrated on Langerhans cell histiocytosis, have furthered our understanding of this enigmatic disease.

Histiocitosis de células de Langerhans

Histiocytoses originate from the proliferation of mononuclear phagocytes in different tissues. These entities make up a heterogeneous group, and are mainly classified as Langerhans cell histiocytoses and non-Langerhans cell histiocytoses. Langerhans cell histiocytoses have as a common characteristic the proliferation of dendritic antigen-presenting cells with phenotypical and ultrastructural characteristics of Langerhans cells. Infiltration may be limited to one organ, or may be disseminated. The prognosis and the treatment especially depend on the age of the patient and the number and dysfunction of the organs involved. Its etiopathogenesis is unknown, although most researchers currently believe that an alteration in the regulation of the immunological system occurs in these patients.

Tumor necrosis factor, interleukin 11, and leukemia inhibitory factor produced by Langerhans cells in Langerhans cell histiocytosis

OBJECTIVES

: The etiology and pathophysiology of Langerhans cell histiocytosis (LCH) remain elusive. The 3-year survival in pediatric multisystem LCH is still around 80%, and children with risk organ involvement (i.e., liver, spleen, hematopoietic system, or lungs) have a less favorable outcome. To further elucidate the pathogenesis of LCH in the search for a rationale cure, the authors investigated intracellular synthesis of tumor necrosis factor (TNF), interleukin (IL)-11, and leukemia inhibitory factor (LIF) from biopsied lesions.

METHODS

: Lesional cells were obtained by fine-needle aspiration biopsy from nine children with LCH. The study was accomplished by the use of an immunofluorescence staining method that allowed cytokine-producing cells to be differentiated from cytokine-binding cells.

RESULTS

: All patients had histiocytes expressing TNF. Seven patients had histiocytes expressing IL-11 and six patients had histiocytes expressing LIF. The two children with the highest proportion of histiocytes displaying TNF and the three with the highest proportion of histiocytes expressing IL-11 and LIF all had risk organ involvement. Two-color staining revealed that histiocytes expressing TNF, IL-11, and LIF co-expressed CD1a molecules.

CONCLUSIONS

: These observations suggest that LCH represents a cytokine-driven condition partially mediated by TNF, IL-11, and LIF. These three cytokines are all osteoclastogenic, suggesting a pathogenetic pathway for the osteolytic lesions in LCH. Furthermore, thrombocytosis in LCH may be explained by IL-11 and LIF activity.

Langerhans cell histiocytosis: an evaluation of histopathological parameters, demonstration of proliferation by Ki-67 and mitotic bodies

PURPOSE

Langerhans cell histiocytosis (LCH) is a disease with a variable clinical manifestation, being localised (SS) or disseminated (MS). The etiology and pathogenesis of LCH is unknown. It is a proliferative disorder of monoclonal origin, but not necessarily neoplastic. In our study we evaluated histopathological parameters and proliferative activity in LCH.

MATERIALS AND METHODS

Infiltrates from 43 patients with LCH were investigated (nSS=32, nMS=11). We evaluated different histopathological parameters semiquantitatively, demonstrating proliferation using immunohistochemistry for Ki-67.

RESULTS

Overall, the histopathological picture of LCH was heterogeneous. The degree of eosinophilia and presence of necroses was significantly higher in SS-infiltrates compared to MS-infiltrates. Mitotic figures were detected in more than half the infiltrates. The Langerhans origin was verified by CD1a. Ki-67 was highly expressed in all but one infiltrate.

CONCLUSIONS

The presence of necrosis and the degree of eosinophilia are related to SS-disease in our study. Ki-67 expression and the presence of mitotic figures indicate that local proliferation contributes to the accumulation of Langerhans cells. Supported by the histopathological appearance of the lesions and a level of Ki-67 expression lower than that of neoplastic tissue, we suggest that LCH is a reactive condition, possibly induced by immunostimulation caused by unknown agents.

Gaucher's disease: morphological findings in a case studied with fine needle aspiration

Fine needle aspiration (FNA) is a diagnostic tool whose inexpensiveness, simplicity and innocuousness have led it to be increasingly accepted in daily medical practice. This method, which is useful for the study of lesions that are accessible by radiological exploration or palpation, provides information about the cytological aspects of punctured lesions. Sometimes, such information can be extended to the histological area through study of cell blocks, true microbiopsies, which are of great diagnostic use. This was the technique used in the case described in the present report.

Need for a cooperative study: Pulmonary Langerhans cell histiocytosis and its management in adults

BACKGROUND

Pulmonary involvement with Langerhans cell histiocytosis (LCH, formerly known as histiocytosis-X) presents as an interstitial process in children and adults either with or without symptoms. In contrast to other manifestations of LCH, most patients with pulmonary disease are adults.

PROCEDURES

We reviewed the literature on pulmonary LCH to determine what were the clinical presentations, prognostic variables, and treatment options for this disease.

RESULTS

Although there are spontaneous remissions, a large number of patients have progressive pulmonary deficiency and experience significant morbidity if not mortality from the disease. The efficacy of steroid versus chemotherapy in halting the process remains controversial, even if smoking is taken into consideration.

CONCLUSIONS

A multicenter study of therapy for pulmonary LCH is the obvious answer to this dilemma. We propose that interested centers organize via the Histiocyte Society to plan and execute such a trial.

Detection of Langerhans cell histiocytosis lesions with somatostatin analogue scintigraphy--a preliminary report

BACKGROUND

Langerhans cell histiocytosis (LCH) is a disease where granulomatous lesions occur in various organs of the body. The etiology and pathogenesis remain unknown. Inflammatory destructive activity give rise to a wide range of clinical symptoms, including fractures, skin lesions, pulmonary fibrosis, endocrinopathies, and central nervous system deterioration. Since disease activity may ultimately lead to fibrosis and organ damage, it is important to have diagnostic tools to detect disease activity early.

PROCEDURE

The present study was undertaken in order to evaluate whether somatostatin analogue scintigraphy ((111)In-pentetreotide or OctreoScan could be used in detecting LCH granulomas and to compare this method with the radiologic methods used today in LCH diagnosis and follow-up. The somatostatin analogue octreotide used here binds to the cell membrane of activated lymphocytes expressing somatostatin receptors.

RESULTS

In five out of six children studied, LCH lesions detected by other means were also detected with (111)In-pentetreotide. It can be speculated that the lesion in the remaining patient was not active at the time of investigation. In addition, in two of the patients signs of disease activity not previously known were revealed.

CONCLUSION

(111)In-pentetreotide can be used to detect active LCH lesions. Since the biologically active somatostatin analogue decreases inflammatory activity, this may also be of therapeutic value in selected patients with LCH. More studies are needed to evaluate the diagnostic and potential therapeutic usefulness of this radionuclide.

Langerhans' cell histiocytosis on the vulva

BACKGROUND

Langerhans' cell histiocytosis (LCH) affecting the vulva alone is rare. At present, there are 51 published cases of LCH affecting the genital area. Of these, only 7 had LCH located in the genital area alone; in these cases, there was no subsequent systemic spread of the disease. A report of the 8th such case is presented with a review of the previous 7 cases.

CASE

A 40-year-old white woman presented with a several-month history of pruritic and ulcerous lesions on the vagina which had then spread to the vulva. No tiredness, general malaise, or associated temperature was observed. Physical examination disclosed an erythematous plaque on the labia minora, which was bilateral and slightly infiltrated. The rest of the physical examination brought no other disorders of interest to light. Histological findings were characteristic of LCH. Four cycles of iv vincristine (2 mg/m cycle) 15 days apart did not obtain objective or symptomatic improvement in the vulvar lesions. Therefore, a local and partial extirpation of both labia minora was performed. Eighteen months after surgery, the patient has no symptoms or signs of local recurrence or systemic spread.

CONCLUSIONS

Although the occurrence of LCH on the vulva is very unusual, we must bear this possibility in mind when a woman presents atypical chronic lesions on the genital mucosa. In such cases, it is necessary to perform a biopsy on the mucosa, rule out the possibility of systemic disease, and review the patient periodically in order to forestall a possible spread of the disease at any time.

Evaluation of human herpesvirus type 8 infection in childhood langerhans cell histiocytosis

The etiology of Langerhans cell histiocytosis (LCH) is unknown. Viral causes, including human herpesvirus type 6 (HHV6), have been suggested but remain unproved. The recently discovered human herpesvirus type 8 (HHV8), the cause of Kaposi's sarcoma, infects dendritic cells in the bone marrow associated with multiple myeloma. Evidence for an association of HHV8 infection with LCH in children was studied by two approaches: indirectly by HHV8-specific serologic assays and directly by detection of HHV8 sequences using polymerase chain reaction in affected bone marrow samples. Using three different assays specific for HHV8 antibodies, 3 of 10 (30%) children with LCH had detectable HHV8 antibodies, which was not different from the prevalence of 5 of 30 (17%) in healthy controls of similar age (P = 0.65). Of bone marrow samples from three additional children with LCH, all had amplifiable DNA but were negative for HHV8 sequences. These studies of a small number of patients do not demonstrate an increased prevalence of HHV8 infection in children with LCH, and they do not suggest a causal role for HHV8 in the etiology of LCH.

Langerhans cell histiocytosis: diagnosis, natural history, management, and outcome

BACKGROUND

The objective of this descriptive analysis of a large cohort of patients with Langerhans cell histiocytosis (LCH) was to add to the understanding of the natural history, management, and outcome of this disease.

METHODS

Three hundred fourteen Mayo Clinic patients with histologically proven LCH were categorized into those patients with multisystem disease and those patients with single system disease. Clinical features, treatment, and outcome were determined from the case history notes and tumor registry correspondence. Treatment included chemotherapy, radiotherapy, and surgical excision. The end points were disease free survival, active disease, or death. The median time of follow-up was 4 years (range, 1 month to 47.5 years).

RESULTS

The age of the patients ranged from 2 months to 83 years. Of the 314 patients, there were 28 deaths. Multisystemic LCH was found in 96 patients, 25 of whom had continuing active disease after treatment. Isolated bone LCH lesions were observed in 114 of the 314 patients, 111 of whom (97%) achieved disease free survival after treatment. The most common sites of osseous LCH were the skull and proximal femur. Of the 87 patients with isolated pulmonary involvement, only 3 were nonsmokers. After treatment with corticosteroids (+/- cyclophosphamide or busulphan), 74 patients achieved disease free survival, but 10 patients died. Pituitary-thalamic axis LCH, characterized by diabetes insipidus, was found in 44 patients. After treatment, 30 of these patients had disease free survival, but all required long term hormone replacement with desmopressin acetate. Lymph node involvement was found in 21 patients, and mucocutaneous involvement was found in 77 patients.

CONCLUSIONS

Patients with isolated bone LCH lesions have the best prognosis compared with patients with LCH involvement of other systems. By contrast, 20% of patients with multisystem involvement have a progressive disease course despite treatment. The identification of prognostic indicators to facilitate appropriate treatment and long term follow-up surveillance is recommended.

The epidemiology of Langerhans cell histiocytosis

Little progress has been made in finding the causes of LCH. Epidemiologic studies are difficult because of the rarity of this disease. Although several associations have been demonstrated in case-control studies, particularly that with thyroid disease, no causal relationships have been documented. Additional case-control studies may uncover the to-date missing lead that may prove fruitful for epidemiologic investigation.

An update on clonality, cytokines, and viral etiology in Langerhans cell histiocytosis

Many etiologies have been proposed for Langerhans cell histiocytosis (LCH). Recent scientific studies have clearly provided new insights into the etiology and pathogenesis of the disease. The possible role of viruses has not been completely negated, but no viral genomes have been consistently detected in LCH lesions. Other studies do not indicate that LCH arises from a primary defect in the immune system, although altered immune responses and immune dysfunction may play a role in the pathophysiology of the disease. Definitive results have been gained from molecular studies of clonality, however. These have definitively established that LCH is a clonal histiocytic disease rather than a reactive polyclonal disorder.

p53 expression in Langerhans cell histiocytosis

PURPOSE

Langerhans cell histiocytosis (LCH) is a disorder of unknown etiology involving the proliferation and accumulation of cells with the phenotype of a bone marrow-derived antigen-presenting cell of the skin, the Langerhans cell. We have studied p53 expression, an element in the control of cell proliferation, to determine whether it plays a role in the pathogenesis of LCH.

PATIENTS AND METHODS

LCH lesions from 10 patients with either localized (n = 5) or multisystem disease (n = 5) were studied. p53 protein expression was assessed by immunohistochemistry, and p53 gene mutation by the single strand conformation polymorphism (SSCP) technique.

RESULTS

p53 protein expression was detected in all 10 LCH biopsy specimens examined. It was restricted to Langerhans cells (LCH cells), absent from adjacent cells, and localized to the cell nuclei. No mutations of the p53 gene were detected, nor was there abnormal expression of the p53 binding protein, mdm2.

CONCLUSIONS

p53 is readily detectable in LCH cells but not in normal cells. This is either caused by an unusual mechanism (given the absence of mutations in the p53 gene and of mdm2 expression in LCH cells) or by overexpression or posttranslational changes of normal p53 in response to an as yet unidentified cellular stress. Stabilization and inactivation of p53 could lead to the uncontrolled proliferation of LCH cells, or the abnormality could lead to the induction of programmed cell death.

Langerhans cell histiocytosis (histiocytosis X)

There has been a renewed interest in Langerhans cell histiocytosis in recent years due both to advances in basic research and to improvements in diagnostic and treatment approaches. In this article, we review the various aspects of the disease and the potential implications of these recent scientific researches for our understanding and management of the disorder.

Epidemiologic study of Langerhans cell histiocytosis in children

OBJECTIVE

The etiology and pathogenesis of Langerhans cell histiocytosis (LCH) remain poorly understood. We conducted an exploratory epidemiologic study to investigate potential risk factors associated with LCH.

STUDY DESIGN

We used a case-control study design to obtain data from parents of children with LCH (n = 459) who were members of the Histiocytosis Association of America and Canada. The two control groups consisted of 683 community control subjects and 3719 children with childhood cancers treated at participating Children's Cancer Group institutions.

RESULTS

The median age at diagnosis of LCH was 1.8 years (range 0.1 to 14.6 years). Cases were categorized as multisystem LCH (MS-LCH) (n = 208) and single-system LCH (SS-LCH) (n = 198). Statistically significant associations included the following: infections in the neonatal period (MS-LCH, odds ratio (OR) = 2.2), solvent exposure (SS-LCH, OR = 54.9), childhood vaccinations (MS-LCH and SS-LCH, OR = 0.4), thyroid disease in the proband (MS-LCH and SS-LCH, OR = 21.6), and family history of thyroid disease (MS-LCH and SS-LCH, OR = 1.4). The association with thyroid disease in the proband was explained partially by the involvement of the pituitary, with the relative risk decreasing when patients with diabetes insipidus and thyroid involvement were excluded from analysis.

CONCLUSIONS

This large hypothesis-generating study provides directions for future investigations in well-designed population-based or hospital-based epidemiologic studies.

Pediatric dermatology

The latest studies regarding the controversial and concerning subjects of pigmented nevi and melanoma in children are reviewed. Additional topics covered include dermatologic conditions that feature genetic mosaicism, theories of pathogenesis of Langerhans cell histiocytosis, new clinical information regarding juvenile xanthogranulomas, and the unique features of pyoderma gangrenosum in infants and children.