Aggressive histiocytic disorders that can involve the skin

Cutaneous Manifestations of Langerhans Cell Histiocytosis in Pediatric Age: A Case Report

Langerhans cell histiocytosis (LCH) is a rare histiocytic neoplastic disorder that mainly affects the skin and bones, with dermatological manifestations that can be easily confused with other dermatological conditions, such as seborrheic eczema, psoriasis, lesions of herpes simplex virus infection, fungal infection, lichen planus, and cutaneous lymphomas. This case report describes an eight-month-old infant who, at a child health appointment, presented with progressive erythematous papulovesicular lesions, initially treated with hygiene measures (skin hydration and hygiene) and mupirocin ointment, but which persisted and worsened, leading to a skin biopsy. The diagnosis of self-limiting congenital histiocytosis was confirmed, and the child was referred to the Portuguese Oncology Institute. The case highlights the importance of early recognition of LCH, the multidisciplinary approach, and the crucial role of the family doctor in the diagnosis and appropriate management of this rare condition.

Renal Cell Tumor and Cystic Lung Disease: A Genetic Link for Generalists to Be Aware of

Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant condition characterized by multiple pulmonary cysts, fibrofolliculomas, and renal cell carcinoma. The typical presentations leading to diagnosis include fibrofolliculomas and spontaneous pneumothoraxes. We present a case of a 52-year-old Chinese male who was diagnosed with BHDS after the incidental pickup of an echogenic heterogenous lesion on an abdominal ultrasound done to investigate an abnormal liver function test. The presence of renal cell carcinoma with cystic pulmonary disease should prompt the clinician to consider the diagnosis of BHDS. Knowledge of extrapulmonary findings of common cystic lung diseases may contribute to improved diagnosis of this condition.

Cutaneous Mastocytosis in Childhood-Update from the Literature

Mastocytosis (M) represents a systemic pathology characterized by increased accumulation and clonal proliferation of mast cells in the skin and/or different organs. Broadly, M is classified into two categories: Cutaneous mastocytosis (CM) and systemic mastocytosis (SM). In children, CM is the most frequent form. Unfortunately, pathogenesis is still unclear. It is thought that genetic factors are involved, but further studies are necessary. As for features of CM, the lesions differ in clinical forms. The most important fact is evaluating a pediatric patient with CM. It must comprise laboratory exams (with baseline dosing of total serum tryptase), a skin biopsy (with a pathological exam and, if the diagnosis is unclear, immunohistochemical tests), and a complete clinical evaluation. It is also defining to distinguish between CM and other diseases with cutaneous involvement. As for the management of CM in children, the first intervention implies eliminating trigger factors. The available cures are oral H1 and/or H2 antihistamines, oral cromolyn sodium, oral methoxypsoralen therapy with long-wave psoralen plus ultraviolet A radiation, potent dermatocorticoid, and calcineurin inhibitors. In children, the prognosis of CM is excellent, especially if the disease's onset is in the first or second years of life.

LCH of the Scapula in a 2-Year-Old Masquerading as an ABC: A Case Report and Literature Review

We describe a unique case of Langerhans Cell Histiocytosis (LCH) arising in the scapula of a 2-year old male child masquerading as an aneurysmal bone cyst (ABC) at clinical presentation and on imaging. Scapular involvement is only occasionally noted in LCH cases. Solitary bone involvement in our patient’s age group is uncommon in LCH without multi-organ involvement. Careful pathologic examination and immunohistochemistry was crucial in establishing this diagnosis due to the presence of a solitary lesion with fluid-fluid levels.

Cutaneous Manifestations in a Patient With Reactive Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare hematologic disease caused by a disordered immune system. We present a case of reactive HLH (RHLH) with uncommon skin findings in a 35-year-old African American female with a history of hidradenitis suppurativa and morbid obesity. Skin findings on physical exam revealed bullous, ecchymotic, hypopigmented, and ulcerated lesions. The literature on the cutaneous lesions of RHLH is limited. Skin findings are an underrecognized feature of RHLH and can help alert to its presence or its recurrence after treatment.

Juvenile Xanthogranuloma: An Entity With a Wide Clinical Spectrum

Juvenile xanthogranulomas (JXGs) are rare, benign lesions that belong to the large group of non-Langerhans cell histiocytoses. JXG presents with 1 or more erythematous or yellowish nodules that are usually located on the head or neck. Most JXG lesions are congenital or appear during the first year of life. Extracutaneous involvement is rare, but the literature traditionally suggests investigating the possibility of ocular compromise. JXG is mainly a clinical diagnosis, but a skin biopsy may sometimes be needed for confirmation. JXGs on the skin are self-limiting and usually do not require treatment. This review describes the clinical and therapeutic aspects of JXG, emphasizing available evidence and the diagnosis of extracutaneous involvement.

Genital Ulcer Disease: A Review of Pathogenesis and Clinical Features

Genital ulcer disease can be caused by a wide variety of sources. Most commonly, genital ulcer disease is grouped into infectious and noninfectious causes. HSV, syphilis, lymphogranuloma venereum, and chancroid represent some common infectious ulcers. Noninfectious causes on the other hand can be inflammatory, noninflammatory, or malignant (eg, squamous cell carcinoma). Depending on the etiology, genital ulcers may present with unique features that can help clinicians identify the etiology and start treatment in a timely manner. The clinical presentation and management of infectious and noninfectious genital ulcers will be discussed in this review.

Cutaneous Involvement of Hematologic Malignancies

In reviewing cutaneous manifestations of various hematologic malignancies, the authors focus on secondary cutaneous lymphomas and cutaneous manifestations of histiocyte disorders. Secondary cutaneous lymphomas are defined as skin lesions that develop secondary to infiltration by systemic lymphomas with predominantly extracutaneous involvement. In their review of histiocytic disorders with skin involvement, the authors focus on Langerhans cell histiocytosis and Rosai-Dorfman disease. Their review emphasizes the histology, pathophysiology, clinical presentation, prognosis, and treatments available for these diseases.

Giant Juvenile Xanthogranuloma: Case Report, Literature Review, and Algorithm for Classification

Juvenile xanthogranuloma (JXG) is a member of the non-Langerhans cell group of proliferative disorders of mononuclear phagocytes. JXG is a benign tumour of histiocytic cells. Classic JXG is divided into 2 main clinical subtypes: dome-shaped papules (<0.5 cm) and single/multiple nodules (<2.0 cm). A rare variant is referred to as giant; this term encompasses JXG lesions larger than 2.0 cm. In this article, we report a case of a congenital cutaneous giant JXG. In addition, we reviewed and analyzed all cases (n = 51) of giant JXG reported in the English literature. We propose an algorithm for classifying giant JXG based on the following factors: onset of lesions (congenital and acquired), number of lesions (solitary ± satellites and multiple), morphology of cutaneous/mucosal lesions (plaque, nodular, ulcerated-nodular, macular, and other), and extracutaneous manifestations.

Primary cutaneous histiocytic sarcoma: A report of five cases with primary cutaneous involvement and review of the literature

INTRODUCTION

Histiocytic sarcoma is an extremely rare hematologic malignancy of histiocytic origin. Five cases of primary cutaneous histiocytic sarcoma are presented.

MATERIALS AND METHODS

Cases of primary cutaneous histiocytic sarcoma were identified using a natural language search from the dermatopathology data base of Cornell University.

RESULTS

There was a male predominance (4 males and 1 female) ranging in age from 33years to 92years (mean age of 73years); all presented with a solitary nodule which involved the head and neck area in four and thigh in one. The 73-year-old male had chronic myeloproliferative disorder. Biopsies showed a nonepitheliotropic dermal-based atypical large cell histiocytoid appearing infiltrate dermis showing positivity for common leukocyte antigen, CD4, CD14, CD68, CD163, CD2, CD11c, and lysozyme. Markers of terminal histiocytic differentiation such as S100, langerin, MXA, and CD83 were not seen. In two of the cases there was evidence of extracutaneous dissemination. The treatment in three of the cases was wide excision; there was no evidence of recurrent or metastatic disease. One case was given palliative radiation; the patient died. The other patient with underlying myelodysplastic syndrome died within a few weeks of initial cutaneous presentation.

CONCLUSION

HS must be differentiated from other malignant histiocytoid lesions. Staining for common leukocyte antigen and CD163 are the most reliable markers allowing this distinction. Patients who present with primary involvement of the skin may have a favorable outcome but only if treated relatively early in the course of the disease with complete excision.

Granulomatous & histiocytic dermatitides

Granulomas of the skin may be classified in several ways. They are either infectious or non-infectious in character, and they contain areas of necrobiosis or necrosis, or not. Responsible infectious agents may be mycobacterial, fungal, treponemal, or parasitic organisms, and each case of granulomatous dermatitis should be assessed histochemically for those microbes. In the non-infectious group, examples of necrobiotic or necrotizing granulomas include granuloma annulare; necrobiosis lipoidica; rheumatoid nodule; and lupus miliaris disseminates faciei. Non-necrobiotic/necrotizing and non-infectious lesions are exemplified by sarcoidosis; foreign-body reactions; Melkersson-Rosenthal syndrome; Blau syndrome; elastolytic granuloma; lichenoid and granulomatous dermatitis; interstitial granulomatous dermatitis; cutaneous involvement by Crohn disease; granulomatous rosacea; and granulomatous pigmented purpura. Histiocytic dermatitides that do not feature granuloma formation are peculiar reactions to infection, such as cutaneous malakoplakia; leishmaniasis; histoplasmosis; lepromatous leprosy; rhinoscleroma; lymphogranuloma venereum; and granuloma inguinale.

Combined Cutaneous Rosai-Dorfman Disease and Localized Cutaneous Langerhans Cell Histiocytosis Within a Single Subcutaneous Nodule

Rosai-Dorfman disease (RDD) is a reactive multisystem histiocytosis that typically presents with cervical lymphadenopathy and systemic symptoms. Cutaneous involvement occurs in approximately 10% of cases, and 3% of cases are limited to the skin without nodal or other extranodal involvement. Langerhans cell histiocytosis (LCH) is a clonal histiocytosis with a wide spectrum of presentations ranging from isolated skin or bone disease to multisystem involvement. Rare case reports have identified concomitant presentation of RDD and LCH; however, most of these reports have involved LCH and RDD occurring concurrently but at separate sites. We present a rare case of concurrent RDD and LCH presenting within a single skin nodule. The patient did not have any evidence of systemic involvement and has remained stable without additional treatment. We also review the literature on this unusual co-presentation and suggest possible underlying mechanisms. Finally, we recommend baseline laboratory and imaging studies and discuss treatment options based on the available evidence.

Non-sclerotic bone involvement in Erdheim-Chester: PET/CT and MRI findings in a 15-year-old boy

Erdheim-Chester disease is a rare form of non-Langerhans cell histiocytosis with multi-organ infiltration that occurs mainly in adults. Pediatric cases are extremely rare. Here we report a case of multisystemic Erdheim-Chester disease in a 15-year-old boy with central nervous system involvement and skeletal findings. Positron emission tomography (PET) and MRI were used to demonstrate characteristic bilateral, symmetrical medullary involvement of the metadiaphyses of long bones in the absence of the classic sclerotic radiographic appearance. This illustrates the potential for earlier diagnosis and visualization of therapeutic response in children.

Purely cutaneous Langerhans cell histiocytosis presenting as an ulcer on the chin in an elderly man successfully treated with thalidomide

Langerhans cell histiocytosis (LCH) is a rare, clonal proliferative disorder of Langerhans’ cells of unknown etiology. Although the clinical presentation and therapeutic approach to the disease in children have been well established; limited data is available about the disease in adults. Purely cutaneous involvement of LCH in a man older than 70 years has rarely been described. Herein we report the case of a 71-year-old man with cutaneous LCH confined to the perioral region, scalp, and flexures successfully treated with thalidomide.

Langerhans cell histiocytosis and Erdheim-Chester disease, both with cutaneous presentations, and papillary thyroid carcinoma all harboring the BRAF(V600E) mutation

Langerhans cell histocytosis (LCH) and Erdheim-Chester disease are two rare histiocytic disorders. Their occurrence in the same patient is more infrequent, but has been described. We report a case of a 38-year-old woman who presented with a diagnosis of single system cutaneous LCH. Subsequently, she developed multiple papules on her extremities consistent with a non-LCH xanthogranuloma type lesion. BRAF(V600E) mutation immunostain, VE1 was positive in the skin lesion, which was confirmed by molecular polymerase chain reaction (PCR) studies, initiating a complete systemic workup for Erdheim-Chester disease. Systemic involvement was confirmed with bilateral sclerotic bone lesions and retroperitoneal and pelvic fibrosing disease. She was also found to have a BRAF(V600E) mutation positive papillary thyroid carcinoma. New suspicious cutaneous lesions presenting in patients with a history of LCH need to be biopsied. A BRAF(V600E) mutation in a non-LCH histiocytic lesion with a xanthogranuloma phenotype (CD163/CD68/CD14/fascin/Factor 13a) should prompt an Erdheim-Chester disease workup. This is a unique case of a woman with BRAF(V600E) mutation positive Erdheim-Chester disease and cutaneous LCH, while also being, to our knowledge, the first reported case in the English literature of it occurring in a patient with a BRAF(V600E) mutation positive papillary thyroid carcinoma.

Pulmonary Langerhans cell histiocytosis: a comprehensive analysis of 40 patients and literature review

BACKGROUND

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial disease affecting primarily young adult smokers. In order to highlight the clinical features of the disease, we conducted a retrospective analysis on clinical data of PLCH patients followed at our center; moreover, we reviewed the current literature on PLCH.

METHOD AND RESULTS

Between January 2004 and July 2014, 40 patients with PLCH were evaluated at our Division. The average patients' age was 40 (± 14) years, and 22 of them were females. Diagnosis was based on search of CD1a+ cells in the bronchoalveolar lavage (10 patients), lung biopsy (8 patients), or cystic bone lesion's biopsy (2 patients); in 12 patients, diagnosis was achieved on the basis of the clinical-radiological data. The principal manifestation of PLCH was the presence of cysts involving upper lung zones with costophrenic sparing on chest CT scan (in 25 patients); micronodular pattern in the middle-upper zone and combination of the two radiological patterns were less frequently observed (in 9 and 6 patients, respectively). Pulmonary hypertension was found in 4 patients. Extra pulmonary manifestations were diabetes insipidus, bone lesions, and skin involvement (in 5, 7, and 1 patient, respectively). For 25 patients, smoking cessation was the only required therapy. Treatments with low dose of prednisolone, vinblastine and prednisolone, or 6-mercaptopurin were reserved for patients with major pulmonary or extra-pulmonary involvement (for 11, 4, and 5 patients, respectively). In conclusion, PLCH is a rare, multi-systemic disease; early diagnosis, accurate staging and smoking cessation are considered critical in PLCH management.

Langerhan Cell Histiocytosis: A Rare Disorder With a Rare Presentation

Langerhans cell histiocytosis (LCH) is a rare disorder most commonly seen in Caucasians of Northern European decent, male, children. The most common presentation is osteolytic bone lesions. A 44-year-old native American presents with diffuse erythematous, scaling lesions. The patient also had pruritus and lymphadenopathy. These lesions were positive for S-100 and CD1a. The patient was started on chemotherapy which improved her symptoms immensely. This was a rare disease with a rare presentation.

Epstein-Barr virus: dermatologic associations and implications: part II. Associated lymphoproliferative disorders and solid tumors

Epstein-Barr virus (EBV) was the first human virus to be associated with oncogenesis. Over the past few decades, cumulative research has revealed that latent EBV infection may be implicated in the pathogenesis of a heterogeneous group of lymphoproliferative disorders and malignancies occurring in both immunocompetent and immunocompromised hosts. Many of these diseases have either primary or secondary cutaneous manifestations. Serologic studies and EBV-encoded RNA in situ hybridization stains have been used to show the association of EBV with disease; while these findings may imply a role, they do not equate with causation. In part II of this continuing medical education review, the salient features of EBV-associated lymphoproliferative disorders and solid tumors are detailed.

Clinicopathologic characteristics and outcomes of histiocytic and dendritic cell neoplasms: the moffitt cancer center experience over the last twenty five years

Neoplasms of histiocytic and dendritic cells are rare disorders of the lymph node and soft tissues. Because of this rarity, the corresponding biology, prognosis and terminologies are still being better defined and hence historically, these disorders pose clinical and diagnostic challenges. These disorders include Langerhans cell histiocytosis (LCH), histiocytic sarcoma (HS), follicular dendritic cell sarcoma (FDCS), interdigtating cell sarcoma (IDCS), indeterminate cell sarcoma (INDCS), and fibroblastic reticular cell tumors (FRCT). In order to gain a better understanding of the biology, diagnosis, and treatment in these rare disorders we reviewed our cases of these neoplasms over the last twenty five years and the pertinent literature in each of these rare neoplasms. Cases of histiocytic and dendritic cell neoplasms diagnosed between 1989–2014 were identified using our institutional database. Thirty two cases were included in this analysis and were comprised of the following: Langerhans cell histiocytosis (20/32), histiocytic sarcoma (6/32), follicular dendritic cell sarcoma (2/32), interdigitating dendritic cell sarcoma (2/32), indeterminate dendritic cell sarcoma (1/32), and fibroblastic reticular cell tumor (1/32). Median overall survival was not reached in cases with LCH and showed 52 months in cases with HS, 12 months in cases with FDCS, 58 months in cases with IDCS, 13 months in the case of INDCS, and 51 months in the case of FRCT. The majority of patients had surgical resection as initial treatment (n = 18). Five patients had recurrent disease. We conclude that histiocytic and dendritic cell neoplasms are very rare and perplexing disorders that should be diagnosed with a combination of judicious morphology review and a battery of immunohistochemistry to rule out mimics such as carcinoma, lymphoma, neuroendocrine tumors and to better sub-classify these difficult to diagnose lesions. The mainstay of treatment for localized disease remains surgical resection and the role of adjuvant therapy is unclear. In patients with multiple areas of involvement, treatment at tertiary care centers with multimodality treatment is likely needed. Accurate subset diagnosis will contribute to better data as well as treatment outcomes analysis of these rare disorders of adult patients in the future.

Epstein-Barr virus and skin manifestations in childhood

Epstein-Barr virus (EBV) is a human B-lymphotropic herpes virus and one of the most common viruses in humans. Specific skin signs related to EBV infection are the exanthem of mononucleosis, which is observed more frequently after ingestion of amoxicillin, and oral hairy leukoplakia, a disease occurring mostly in immunocompromised subjects with HIV infection. Other more uncommon cutaneous disorders that have been associated with EBV infection include virus-related exanthems or diseases such as Gianotti-Crosti syndrome, erythema multiforme, and acute genital ulcers. Other skin manifestations, not correlated to virus infection, such as hydroa vacciniforme and drug-induced hypersensitivity syndrome have also been linked to EBV. The putative involvement of EBV in skin diseases is growing similarly to other areas of medicine, where the role of EBV infection is being investigated in potentially debilitating inflammatory diseases. The prognosis of EBV infection in healthy, immunocompetent individuals is excellent. However, lifelong infection, which is kept in check by the host immune system, determines an unpredictable risk of pathologic unpredictable scenarios. In this review, we describe the spectrum of non-tumoral dermatological manifestations that can follow EBV primary infection or reactivation of EBV in childhood.

[Cutaneous Rosai-Dorfman syndrome. Successful therapy with intrralesional corticosteroids]

BACKGROUND

Cutaneous Rosai-Dorfman disease is a rare disorder belonging to the spectrum of non-Langerhans cell histiocytoses. It is characterized by dermal and subcutaneous infiltrates of histiocytes as well as accompanying lymphocytes, plasma cells and granulocytes. Because it is so rare, standard therapies have not been established.

CASE REPORT

A 27-year-old man showed an excellent response to intralesional corticosteroids after unsuccessful prior treatment with methotrexate, systemic steroids and surgery as well as laser therapy.

An 8-month-old girl with an enlarging lesion on her face. Juvenile xanthogranuloma

An otherwise healthy 8-month-old girl presented to the pediatric dermatology clinic for evaluation of an enlarging lesion on her right cheek. The child's mother first noticed this "bump" a month prior to presentation and denied any inciting event. The lesion had increased in size since it was first noted but was not symptomatic. No bleeding was noted. Perinatal history and review of systems were unremarkable. On physical examination, a solitary, well-demarcated, 3-mm yellow erythematous papule with central erosion was noted on the right upper cheek. No other lesions were identified. Lymph node examination was unremarkable. Clinical observation was recommended, with excision if significant enlargement or atypical features developed. Two months later, the lesion remained asymptomatic but had grown to 9 mm in size. The central erosion persisted, but no bleeding occurred.

BRAF V600E-Positive Multisite Langerhans Cell Histiocytosis in a Preterm Neonate

Hemorrhagic pustules with a "blueberry muffin" appearance accompanied by respiratory failure in a neonate present a challenging differential diagnosis that includes infections and neoplasms. We present a case of multiorgan, multisite Langerhans cell histiocytosis (LCH), positive for the oncogenic BRAF V600E mutation, in a preterm neonate. Infants with LCH pose a diagnostic challenge due to their heterogeneous presentations. This case is unusual in that the newborn presented with severe multiorgan involvement. Due to the rare incidence, wide spectrum of clinical manifestations, and high mortality rate, clinicians must maintain a high index of suspicion for LCH.

Wiskott-Aldrich syndrome caused by a new mutation associated with multifocal dermal juvenile xanthogranulomas

Wiskott-Aldrich syndrome is a rare X-linked primary immunodeficiency clinically characterized by the triad of microthrombocytopenia, immunodeficiency, and eczema. Juvenile xanthogranuloma is a well-recognized benign disorder of infancy and early childhood from the group of non-Langerhans cell histiocytoses, with a good prognosis and spontaneous involution. We report a boy with Wiskott-Aldrich syndrome caused by a new, not previously described mutation associated with multifocal juvenile xanthogranuloma.

Fibrohistiocytic tumors and related neoplasms in children and adolescents

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called "facultative fibroblast," as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Nonlipidized juvenile xanthogranuloma: an unusual variant with a potential diagnostic pitfall

Juvenile xanthogranuloma (JXG) is a histiocytic inflammatory disorder that can present different histologic patterns. Classic JXG consists of sheets of foamy histiocytes and numerous multinucleated Touton giant cells. Nonlipidized JXG (NJXG) is one of the unusual variants of JXG, consisting of a diffuse monomorphic infiltrate of mononuclear histiocytes, suggesting an aggressive or malignant tumor due the high mitotic index. However, NJXG behaves clinically as classic JXG. We present an unusual case of a 6-year-old boy who presented an exophytic ulcerated nodule on the lower lip diagnosed as NJXG. The boy is currently well without recurrence three years after surgical excision.

Multicentric reticulohistiocytosis with elevated cytokine serum levels

Multicentric reticulohistiocytosis (MRH) is an uncommon non-Langerhans cell histiocytosis of unknown etiology. It is a multisystem disorder characterised by a papulonodular skin eruption, mainly in the extensor surfaces, and destructive polyarthritis. Histologically, either cutaneous lesions or the synovium show a dense dermal infiltrate of histiocytes and multinucleated giant cells with an eosinophilic granular material in the cytoplasm. In the immunohistochemical analysis these cells stain positively with monocyte/macrophage markers (CD68 and CD45), as well as with certain cytokines (tumor necrosis factor-α, interleukin 1β and interleukin 6). Moreover, recent reports suggest an osteoclastic nature of the infiltrating cells, as they stain strongly with osteoclast tissue lytic markers including tartrate-resistant acid phosphatase and cathepsin K. We report a case of MRH presenting with clinical features of dermatomyositis. Furthermore, the patient showed elevated cytokine serum levels that lowered after therapy.

Juvenile xanthogranuloma in monozygotic twins

Juvenile xanthogranuloma is usually a benign condition mainly seen in infants and children. It frequently presents as asymptomatic discrete papules on the head, trunk, and limbs. Extracutaneous manifestations, most commonly ocular, are rare but may be associated with significant morbidity. The etiology of juvenile xanthogranuloma is uncertain, although the occurrence in monozygotic twins may suggest genetic predisposition.

Organ-specific eosinophilic disorders of the skin, lung, and gastrointestinal tract

Eosinophils are multifunctional leukocytes that increase in various tissues in patients with a variety of disorders. Locally, they can be involved in the initiation and propagation of diverse inflammatory responses. In this review the clinical association of eosinophils with diseases of the skin, lung, and gastrointestinal tract is summarized. An approach to determining the causal role of eosinophils in these diseases is presented. Recent findings concerning molecular diagnosis, cause, and treatment are discussed.

Indeterminate cell histiocytosis in association with acute myeloid leukemia

Indeterminate cell histiocytosis (ICH) is a rare proliferative disorder, in which the predominant cells share morphologic and immunophenotypic features from both Langerhans and non-Langerhans cell histiocytosis. We describe a 62-year-old man presenting a 2-month history of firm nodular lesions on the upper lip. Histopathology, immunohistochemical, and ultrastructural analysis showed typical findings of ICH. The patient was treated with thalidomide and almost complete regression of the lesions was reached within 7 months. Nevertheless, one month after remission, he developed an acute myeloid leukemia of the subtype monocytic leukemia (M5). The patient's condition rapidly worsened and he died due to a respiratory failure four weeks later. We present this case because apart of being rare it joins the effectiveness of thalidomide and the association with an acute monocytic leukemia. A review of the literature is made.

Juvenile xanthogranuloma presenting as a testicular mass in infancy: a clinical and pathologic study of three cases

Juvenile xanthogranulomas (JXG) is a histiocytic disorder whose most common clinical presentation is a solitary cutaneous nodule in a child under 5 years of age, but it has come to be recognized that solitary extracutaneous lesions may present in a number of sites, including the soft tissues and various organs. Involvement of the genitourinary tract has been documented in children with multifocal or systemic JXG. The current report describes our experience with 3 cases of JXG presenting as a solitary mass in the testicle of infants between 2.5 and 13 months without manifestations of JXG elsewhere. The masses were intratesticular and had an infiltrative pattern of interstitial growth by mononuclear, histiocyte-like cells with replacement of seminiferous tubules and involvement of the epididymis whose pattern resembled leukemic and lymphomatous involvement of the testis. Because extracutaneous lesions of JXG may have few or no Touton giant cells, immunohistochemistry is an important adjunct to the histopathologic diagnosis. One of the previous 2 cases in the literature of JXG of the testis recurred after partial resection without an orchiectomy. Neither of the 2 youngest patients has experienced a local recurrence of JXG elsewhere in excess of 1 year since the original orchiectomy. The oldest patient, who was treated with partial orchiectomy, remains free of recurrence after 3 months of follow-up. Though uncommon, JXG joins several other distinctive neoplasms presenting in the infantile testis.

Malignant histiocytosis of the skin: a case report and review of the literature

BACKGROUND

Malignant histiocytosis is a rare neoplasm composed of abnormal histiocytes typically affecting the liver, spleen, lymph nodes, and bone marrow. This entity has been rarely documented involving the skin and has never been reported confined to the skin.

MAIN OBSERVATIONS

A 74-year-old white man presented to the dermatology clinic with complaints of a non-healing ulcerated lesion on his cheek of several months duration. Histopathological examination revealed a poorly circumscribed neoplasm consisting of pleomorphic epithelioid cells with abundant foamy cytoplasm. Immunohistochemistry was positive for CD-43, CD-68, and lysozyme, but negative for CD-3, CD-20, CD-30, CD-34, SMA, CD-1a or S-100. The prominent CD-68 and lysozyme staining along with the histological features, the clinical presentation of erythematous nodules with diffuse erythematous plaques, and absence of bone marrow findings, led to the diagnosis of malignant histiocytosis confined to the skin.

CONCLUSION

Malignant histiocytosis involving the skin is rare. The presence of large pleomorphic epithelioid cells with foamy cytoplasm, with or without engulfed erythrocytes should alert the dermatopathologist to the possibility of malignant histiocytosis. Appropriate immunohistochemical evaluation, including CD-43, CD-68, CD-1a, S-100, and lysozyme, should be completed to confirm the diagnosis.

An Unusual Juvenile Xanthogranulomaon a Finger MCP Joint

Juvenile xanthogranuloma (JXG) is a benign self-limited histiocytic proliferative disorder that usually occurs in early childhood. JXG appears as reddish to yellow, papules, or nodules, and although the head, neck, and trunk are the most frequent locations, it can occur at any body site. However, JXG involving the finger is rare. Histologically, JXG is characterized by an ill-defined, unencapsulated, dense histiocytic infiltrate within the dermis, some of which is contained in Touton giant cells, foreign body giant cells and foamy cells. Because the cutaneous lesions spontaneously regress, treatment is not usually indicated. The authors report a case of JXG in a 4-year-old girl who had tender, yellowish papule on the ventral aspect of the MCP joint of the right fourth finger consistent with JXG.

Diffuse xanthogranulomatous dermatitis and systemic Langerhans cell histiocytosis: A novel case that demonstrates bridging between non-Langerhans cell histiocytosis and Langerhans cell histiocytosis

The advent of electron microscopy and immunohistochemical stains allowed for reclassification of the histiocytoses based on the predominant cell in the infiltrate. Although the current schema simplicity provides a good foundation, some patients display overlapping clinical and immunohistochemical features that defy classification. The patient herein illustrates bridging between histiocytic disorders. Through this case we review the various conditions classified under the non-Langerhans cell histiocytosis and Langerhans cell histiocytosis rubric.

A case of orbital Rosai-Dorfman disease responding to radiotherapy

Rosai-Dorfman disease (RDD) is a rare histiocytic disorder most often characterized by painless cervical lymphadenopathy, but it may also present with orbital disease. The clinical course of RDD is variable; it can be either relapsing-remitting or progressive, and the outcome relates to clinical location and treatment response. Orbital RDD can have an insidious onset and similar presentation to other ophthalmic conditions; this can result in a delayed diagnosis. Nearly all cases of orbital RDD cause visual disturbances and require treatment. Because orbital RDD is an uncommon presentation, a variety of interventions have been employed, including surgery, immunotherapy, chemotherapy, and radiotherapy. We present a case of salvage radiotherapy for progressive orbital RDD refractory to surgery and chemotherapy in a pediatric patient.

Severe congenital systemic juvenile xanthogranuloma in monozygotic twins

Juvenile xanthogranuloma, a histiocyte disorder, usually presents with a solitary cutaneous lesion. Juvenile xanthogranuloma with extracutaneous involvement is a rare disease in which significant morbidity and occasional deaths may occur. Monozygotic twins with congenital systemic juvenile xanthogranuloma who presented with multiple skin lesions, hepatosplenomegaly, liver failure, and bone marrow involvement were reported. The diagnosis of systemic juvenile xanthogranuloma was confirmed by histology and immunohistochemical stains of the skin with liver biopsies revealing dense infiltration of lymphohistiocytes with typical Touton giant cells staining positive for CD68 and negative for CD1a and S-100 protein. Both of them received systemic prednisolone 1 mg/kg/day which was gradually tapered off with time according to clinical and investigative responses. At the 17-month follow-up period, both patients showed remarkable regression in all symptoms and laboratory studies.