Diffuse Cutaneous Mastocytosis: A Current Understanding of a Rare Disease.

Mastocytosis is a heterogeneous disease characterized by the expansion and accumulation of neoplastic mast cells in various tissues. Diffuse cutaneous mastocytosis (DCM) is a rare and most severe form of cutaneous mastocytosis, which typically occurs in childhood. There have been reports of a familial DCM with specific gene mutations, indicating both sporadic and hereditary factors involved in its pathogenesis. DCM is associated with severe MC mediator-related symptoms and an increased risk of anaphylaxis. The diagnosis is based on the appearance of skin lesions, which typically show generalized thickening, erythroderma, blistering dermographism, and a positive Darier's sign. Recognition, particularly in infants, is challenging due to DCMs resemblance to other bullous skin disorders. Therefore, in unclear cases, a skin biopsy is crucial. Treatment focuses on symptom management, mainly including antihistamines and mast cell stabilizers. In extremely severe cases, systemic steroids, tyrosine kinase inhibitors, phototherapy, or omalizumab may be considered. Patients should be equipped with an adrenaline autoinjector. Herein, we conducted a comprehensive review of literature data on DCM since 1962, which could help to better understand both the management and prognosis of DCM, which depends on the severity of skin lesions, intensity of mediator-related symptoms, presence of anaphylaxis, and treatment response.

Natural history and treatment of cutaneous and systemic mastocytosis.

INTRODUCTION: Mastocytosis, a heterogeneous group of disorders, is characterized by an abnormal increase in the number of mast cells that is limited to the skin (cutaneous mastocytosis), involving extracutaneous tissues (systemic mastocytosis), or presenting as solid tumours (mastocytoma and mast cell sarcoma). Recent studies estimate that 1 in 10,000 people are diagnosed with mastocytosis. Although prompt diagnosis and appropriate management are crucial, little is known about the natural history and currently there are no established management guidelines. We have conducted a systematic review to assess the natural history and management of different mastocytosis subtypes. METHODS: A systematic review and meta-analysis were conducted using the PubMed and Ovid database of studies published in English and French over the last fifteen years, from January 2001 to December 2016. Keywords 'Cutaneous mastocytosis', 'Systemic mastocytosis', 'pathophysiology', 'clinical course', 'prognosis', 'drug therapy', and 'therapy' were searched. Rate of complete resolution was subjected to pooled analysis for different mastocytosis subtypes. Meta-analysis was conducted using Stata version 12.0. RESULTS: We reviewed 634 papers, of which 5 were included in the analysis of resolution, and 138 were included in the assessment of management. Pooled estimate for rate of complete resolution varied depending on the mastocytosis subtype. In cutaneous mastocytosis, the complete resolution rate for mastocytoma was 10% per year (95% CI: 4.8%, 15.1%) while the rate for urticaria pigmentosa was 1.9% per year (95% CI: -0.5%, 4.3%). Diffuse cutaneous mastocytosis and systemic mastocytosis subtypes did not show evidence of complete resolution in the studies reviewed. Treatment of cutaneous and systemic mastocytosis is purely symptomatic with topical corticosteroids, antihistamines, omalizumab and imatinib being common choices. CONCLUSION: Rate of resolution of mastocytosis is only shown in urticaria pigmentosa and mastocytoma. Better management guidelines are required to improve the health of these patients.

Molecular defects in mastocytosis: KIT and beyond KIT.

In all variants of mastocytosis, activating KIT mutations are frequently found. In adults, neoplastic mast cells (MCs) cells show the KIT mutation D816V, whereas in children, MCs invading the skin are frequently positive for non-KIT D816V mutations. The clinical course and prognosis of the disease vary among patients with systemic mastocytosis (SM). Additional KIT-independent molecular defects might cause progression. Additional oncogenic lesions have recently been identified in advanced SM. In advanced SM the presence of additional genetic lesions or altered signaling worsening the prognosis might lead to the use of alternative therapies such as combined antisignaling targeted treatments or stem cell transplantation.

The RCPCH care pathway for children with urticaria, angio-oedema or mastocytosis: an evidence and consensus based national approach.

AIMS: The Royal College of Paediatrics and Child Health (RCPCH) Science and Research Department was commissioned by the Department of Health to develop national care pathways for children with allergies; the urticaria, angio-oedema or mastocytosis pathway is the fifth pathway. The pathways focus on defining the competences required to improve the equity of care received by children with allergic conditions. METHOD: The urticaria, angio-oedema or mastocytosis pathway was developed by a multidisciplinary working group and was based on a comprehensive review of evidence. The pathway was reviewed by a broad group of stakeholders including the public and approved by the Allergy Care Pathways Project Board and the RCPCH Clinical Standards Committee. RESULTS: Three pathways are described: urticaria with or without angio-oedema, angio-oedema without weals, and mastocytosis. The results are presented in four parts: evidence review, mapping, external review and core knowledge documents. Acute urticaria has many causes and is often not allergic in origin. It is frequently of relatively short duration and easily managed with antihistamines alone. However, at the other extreme, causes of chronic urticaria and angio-oedema are difficult to diagnose and treatment can be complex. Thus defining the competence required for each extreme is critical to ensure optimal care. The evidence review identified that allergy testing and thyroid function testing were helpful in the investigation of chronic urticaria, that increasing the dose of antihistamine was effective in treating urticaria and that ciclosporin A and prednisolone were effective second line treatments. CONCLUSIONS: From the common presentation of acute (intermittent) urticaria to the uncommon presentations of chronic urticaria, angio-oedema and cutaneous mastocytosis, this pathway is a tool to assist health professionals to differentiate and manage these conditions.

[Systemic mastocytosis--definition of an internal disease]. / Die systemische Mastozytose--Standortbestimmung einer internistischen Erkrankung.

Systemic mastocytosis comprises disorders characterized by an accumulation of genetically altered mast cells in all organs and tissues due to an increased proliferation rate and reduced apoptosis of those pathologic mast cells. Release of their mediators can effectively influence organ function and can lead to systemic effects without inducing traces in routinely used laboratory parameters or imaging methods. In most cases, little invasive investigations allow diagnosing the disease and, hence, an appropriate therapy consisting of a basic medication with antihistamine and mast cell membrane-stabilizing compounds that should be supplemented, if required, by a medication adapted to individual symptoms, can be initiated. Because of the probably high prevalence of the disorder, systemic mastocytosis should be considered as a differential diagnosis in particular in the case of chronic gastrointestinal complaints such as abdominal pain/discomfort possibly associated with diarrhea, at an early stage.

Mastocitosis en un lactante / Mastocytosis in an infant

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Mastocytosis: review of clinical and experimental aspects.

Mastcytosis is a rare disease characterized by an abnormal increase of mast cells in tissues. The skin is the organ most frequently involved, but mast cells also accumulate in the bone marrow, gastrointestinal tract, lymph nodes, spleen, and liver. Recent studies suggest that activating mutations of c-kit, a protooncogene encoding for the receptor (kit) of stem cell factor, are a possible cause of some forms of mastocytosis. In addition, an increased rate of chromosomal aberrations has been found. Despite significant advances in research on mastocytosis, curative treatment is not yet available. Current management is based on avoidance of mediator-releasing triggers and symptomatic treatment.